All About Batteries

TERMINOLOGY

Battery versus a cell: Most people use these words the same way. Battery engineers only use "battery" to refer to two or more individual cells connected together within one package. Thus your watch probably only has a single cell, your flashlight has a couple of cells, and your camcorder has a complex battery with several cells inside the black plastic package. No big deal.

Throw Away or Rechargeable: Engineers call throw-aways "primary," and rechargeables "secondary."

Power is expressed in Watts. Multiply current, measured in Amperes (Amps), by Volts to get power in Watts. Power is the ability to do work. If you imagine this as water in a hose, Volts is the water pressure and amps is how many gallons flow. How much you can spray off your driveway is thus the water pressure times how much water flows at that pressure. Volts, Amps and Watts are always capitalized since they are named after men who invented much of this: Alessandro Volta (Italian) who invented the first battery, James Watt (Scottish) who designed improvements to steam engines and mathematician André-Marie Ampère (French).

Energy is power over time, measured in Watt-seconds (Ws), also called a Joule, named after English physicist James Prescott Joule. A kiloWatt-hour is 1,000 x 60 x 60 or 3,600,000 joules. Flashes often measure their power in Ws, for instance, 50 Ws is normal for a shoe-mounted flash and 500 to 2,000 Ws is common for studio strobes.

Capacity is how much current is stored by a cell. Even throw-away cells have these ratings, although only engineers worry about it or look it up. These ratings are plastered all over rechargeables. It's usually measured in Ampere-Hours or milliAmpere-Hours. 1 Ah is the same as 1,000 mAh. A 1,000 mAh cell can deliver 1,000 mA for an hour, or 1 mA for 1,000 hours.

In reality cells are measured at about a 20 hour discharge rate. Cells have less capacity when more power is drawn, thus a 1,000 mAh cell would probably die after a half hour if delivering 1,000 mA. When capacity is measured it is measured to a stated cut-of voltage and at a stated rate. The same cell will have completely different capacities when measured at different rates and to different cutoff voltages. Therefore when you see these numbers on a package they are meaningless unless the rate and cutoff are specified, which usually they aren't. In addition to plain lying, this explains why you shouldn't bother to compare different brand's ratings to each other.

TECHNOLOGIES

Throw-Away (Primary)

"Heavy Duty"

Avoid these. They are also called carbon zinc, zinc-manganese dioxide, Zn/MnO2, and LeClanché. These are the oldest, crummiest kind. Remember when flashlights only worked for a few minutes before they started to get dim? These were the batteries! They never could deliver much power for anything. You can still get these throughout the third world and in discount stores. I was amused at seeing a Duracell ad poking fun of the Eveready brand of these. It was unfair since Eveready makes both these crappy kind as well as batteries far more advanced. Anyway, ignore these batteries for everything except things with very low drains. Don't use them for a flash. They work great in things that run for a year like smoke detectors and clocks. They die after a couple of years in storage.

Capacity: Eveready Heavy Duty AA: 1,100 mAh.

Alkaline

These are the most popular today and work great. There are some premium versions, like Eveready's e2 Titanium, that work a little better in high-power applications like flashes and digital cameras. Personally I find they cost more than the benefit they offer compared to the regular alkaline batteries. Alkalines come in every size, from regular AA, C and D sizes as well as little button cells for watches and light meters. They last for years in storage. I have a healthy set in a flashlight that still works great even though the install by date passed five years ago.

Capacity, AA size: 2,700 to 3,135 mAh. Most AA Alkaline cells offer a capacity of 2,850 mAh. The expensive Energizer e2 alkaline offer 3,135 mAh and the cheapest cells offer 2,700 mAh, all pretty much alike at low drains. That's why Consumer Report's testing suggested to get whatever's cheapest. Note that "Titanium" is just marketing poof; these are not Lithium or titanium, they're just alkaline.

Because Duracell, Eveready Energizer and Rayovac offer to repair any damage caused by leaking batteries I only buy them, and never store brands. Even though the discount brands offer the same performance for a lot less money, when you eventually have one leak in your camera you'll be very, very glad that you weren't using store brand alkalines! I had a flash damaged once, and the battery company actually sent me a new one! One device damaged but saved by a warranty easily pays for the extra cost.

anasonic Oxyride

Panasonic introduced these in 2005. I have not tried them yet. They sell for the same price as alkaline AA cells. They have a higher initial voltage, 1.7V, compared to ordinary alkalines which are 1.5V. Thus when new flashlights will burn brighter with Oxyride than with other cells. This also means that the bulbs will burn out faster, too.

David Pogue in the NY Times on April 7th, 2005 did the best article I've read on the Oxyrides. You may be able to read it here if you're signed up with the NY Times.

David found that for high-drain applications, specifically in a digital camera, that indeed they lasted for 844 shots compared to 566 for premium alkalines and 354 shots for regular alkalines. GREAT!!!, and at the same price as regular alkalines.

On the other hand David found that the Oxyrides lasted less long than alkalines for low drains. They lasted about as long as alkalines when discharged at a four hour rate. Oxyrides were worse than alkalines at lower drains like a 10 hour rate.

Thus from David's observations Oxyrides are fantastic for high drains like digital cameras and I would suggest them also for electronic flash, but a poor choice for clocks, pagers and radios and things that usually run a long time on a set. For these regular alkaline are still better.

Lithium (note that Lithium also comes as Lithium Ion rechargeables below)

These are expensive. They were developed for the US military because they offer double the power in the same size with half the weight. This is important when you have to carry a month's worth of batteries for your night vision system in your pack. Today these are the batteries that run your camera and cost $10.

Hint: Camera stores make a lot of money selling batteries. Look around online to get much better deals than retail. Lithium batteries have shelf lives of ten years or more, so stock up and don't worry. They come in various special sizes for cameras and also AA. You have no choice for the special camera sizes; they only come in Lithium. You have many choices in AA size, here are some tips.

Capacity: Energizer Lithium AA cells offer 3,000 mAh, the same as Alkaline.

Tip: Use the AA lithiums only for things that draw a lot of power, like a flash or a digital camera. They offer the same life as alkaline in things like clocks and pagers. They offer greater life only when you draw a lot of power as in a digital camera or flash. Otherwise they cost $10 for a set of four compared to 99 cents or less for alkaline. I have never found the lithium AAs for less than about $2 a cell, let me know if you do. Amazon has them for $2.50 each, a pretty good price, here.

Tip: I have not confirmed what the data sheets say personally, however if it ever got as cold as freezing here in California I'd point out that Lithiums are supposed to work better than alkalines at cold (sub-zero) temperatures.

Tip: AA Lithium can't deliver much instantaneous power as other technologies. Thus you get the slowest recycling times in flashes. The lithium cells are designed this way because otherwise the lithium chemistry is so potent it would tend to heat up and explode. You'll get faster flash recycling with rechargeables or even regular alkalines. You will get twice as many flashes with the lithium, just not as fast recycling. This is a minor point. If I had someone else paying for my batteries I'd use lithium AA for everything.

Tip: I've gotten some bargains at as-seen.bizhosting.com and www.batterystation.com. Also ContinentalPhoto.com is suggested by a reader as having great deals on these.

Idea: There is a rechargeable CR-V3 system I've seen circulating under various sub-prime brand names. You can get one here for $30 with the charger and spare batteries here for $20. I've seen claims of these replacing two AA cells in addition to the throw away CR-V3. These only have a capacity of about 1,300 mAh, less than half of a throw away CR-V3 (2,900 mAh) and less than Ni-MH rechargeable AAs (typically 2,300 mAh today). I also see claims of it outrunning Ni-MH, so try it yourself. I'm a cheapskate so I refuse to own anything that uses throw-away $15 batteries, so I have not tried this system. If I used these batteries I'd order one today since as soon as you use it a couple of times you're already ahead.

Mercury (obsolete)

Mercury cells are no longer available in the USA. They were used in cameras from the 1960s and 1970s. Mercury cells had the advantage of constant voltage all the time, so they were ideal as references powering CdS cell light meters.

There's more here on them.

I have had my Luna Pro meter updated to run on ordinary S76 cells and it works great.

Rechargeables (Secondary)

Lead Acid and Gel Cells

The first lead-acid batteries were used for telegraphy by Gaston Planté in 1859 and became available commercially in the 1880s. It's interesting to note how rechargeable batteries have always been involved with communication; your cell phone today runs on a Lithium Ion battery described below. A lead-acid battery starts your car. They are filled with liquid sulphuric acid and you don't want to spill them. Lead acid batteries are also available with gelled acid, called gel cells, which doesn't spill and can be used upside down. Gel cells are used in home alarm systems, backup power systems and your home computer's uninterruptible power supply (UPS) if you have one. Lead acid is not used in photography, except as heavy duty supplies for some lighting equipment.

Care and Use: Lead acid batteries prefer to be kept charged all the time. They can deliver very high power. That's why they are perfect for use in your car: they can deliver thousands of watts to start your car, and then are kept charged as you drive around. Deep cycling them is bad for them, and there are special kinds of lead acid batteries designed for this. Likewise, they are perfect for use in power backup systems where they are very happy being kept charged for years just waiting and can deliver enormous amounts of power instantly. Most television networks each have a room full of lead acid batteries that are always kept charged. If the power goes out these batteries can deliver enough power to run the entire network headquarters for 10 minutes or so if they have to if the Diesel generator doesn't start immediately. Other kinds of battery need exercise; lead acid doesn't.

Charging: Lead acid is very easy to charge. They are charged to a constant voltage through some form of current limiter.

Alkaline: Ray-o-Vac invented rechargeable alkalines in the 1990s. They never caught on.

Nickel-Cadmium (Ni-Cd)

These were the first popular rechargeables for modern electronics. They got popular in the 1960s. They still offer the most charge and recharge cycles of any technology. They also offer the lowest capacity so you'll be charging them much more often. Ni-Cds are unbeaten in their ability to provide dangerous amounts of current instantaneously if short circuited. Therefore they're popular in cordless soldering irons because they heat up instantly. Caution: if you short circuit them with a wire the wire will immediately glow and maybe even burn up. You easily can hurt yourself if you throw them in a pocket with keys or change. This of course is a good thing allowing fast flash recycle times and fast frame rates when used in camera motor drives.

Capacity, AA size: 650 to 1,000 mAh, not very much.

Care and Use: Mandatory: they should always be fully charged and then run all the way down before being charged again. This means for most field uses you need two sets so you have a fresh set with you for when the first set dies. If instead you just charge them up when you need them you eventually will get very little run time. This is called the memory effect. They learn how little you use them and then only provide that much capacity. They're like muscles: you have to use them to keep them strong. You have to baby Ni-Cds so I don't recommend them for anything. They also contain poisonous cadmium and must be disposed of properly. I don't even know where you can buy these today.

Charging: At slow overnight rates even the simplest circuitry has been used to charge Ni-Cds, since you don't have to worry about them overcharging at the slow rate. More advanced circuitry is required to charge them more quickly since the Ni-Cds could blow up at faster charge rates if the charger is not smart enough to cut off the current. Smart chargers today are very common and can charge these in several hours or less. As soon as all the charge is put back you stop charging, simple.

Nickel-Metal Hydride (Ni-MH)

These are the most popular rechargeables today in AA and other regular sizes. They replaced Ni-Cds in notebook computers in the late 1980s and became available in AA size in the 1990s. They offer twice the capacity of Ni-Cds and require less babying. Most chargers recharge them in a couple of hours. Otherwise they are very similar to Ni-Cd, although don't have quite the peak current ability of the Ni-Cds or offer quite as many charge/discharge cycles.

Charging Speed

The electrical energy fed to a cell turns to chemical energy as it charges. When the cell is full the power no longer can turn to chemical energy and instead turns to heat. If the charger isn't smart enough to know when to turn off, which was the case in the 1970s, the charging current needed to be low enough not to damage the cell from overheating. This is why it took 15 hours to charge Ni-Cd cells back then, and why the crummiest chargers still take overnight.

The speed of any charging system today is limited its ability to know when to turn off. If you continue to jam a lot of power into a charged cell it will explode; whoops! Today most Ni-MH and Ni-Cd systems take a few hours. They measure when the cells are full based on voltage fluctuations (they look for a slight dip in voltage signaling a full Ni-MH cell ) and / or the temperature rise that signals the end of charge. The cells are supposed to get hot at the end of charging; that's one way the charger detects when to turn off.

Regular three hour chargers are smart, but since they usually don't monitor each individual cell they still have to be careful since all cells aren't charged at exactly the same time. The first cell to finish charging still has power jammed into it while the other three cells finish up. This limits what's safe.

Rayovac has a unique system that charges their special Ni-MH cells in 15 minutes. They use charging control not just in the charger, but also use chips in each individual cell. This way there is no danger of one cell exploding while the other cells are still charging. With Rayovac's chips in each cell the charger jams in current like there's no tomorrow and each cell shuts off exactly when it needs to. From what I hear these really work well!

Capacity in AA size: 1,350 to 2,500 mAh. Look out, many shifty brands lie about their capacity. 2,300 is pretty standard in 2004 and 1,350 was typical in 1999. My 1999 1450 mAh Sanyos still outperform newer off brands marked 2300 MAH! in big letters, so buy quality and not specs. Anything from battery pioneers GE/Sanyo and Panasonic ought to be great.

Care and Use: They still should be completely run down and then fully charged each time. They give the best service and life this way. Avoid using Ni-MH if you don't intend to run them all the way down each time. I always have two sets with me, so I can replace the set in use when it runs down completely. The advantage of Ni-MH over Ni-Cd is that if they lose capacity from memory issues you easily can rejuvenate them by running them through a full discharge-charge cycle a couple of times. They do have memory issues, which is why you see so many sold as "memory free." Baloney; the problem just goes away easily by fully cycling them. Unlike Ni-Cd, I've gotten great service from every Ni-MH system I've used by always fully cycling it. I've got many more years of service from an old cell phone that used these batteries than the phone service facility could believe, and the Ni-MH AAs I bought 5 years ago still work as well in my flashes and cameras as when I bought them.

Where to get them

I have one of these great systems here. It's great for travel with its small size, a folding built-in plug, needs no cord or external power adaptor and runs on any power worldwide from 100 - 240 V and 50 - 60 Hz. All you need to use it anywhere from Japan to Iraq are a few passive plug adaptors.

Some people, especially amateur radio operators who have been using these things in their walkie talkies for years, love the Maha systems like this one here.

I also have one of these LaCrosse chargers, the best to get for home since it also measures capacity, recycles and even can rejuvenate cells.

If size isn't important, today I'd first try the brilliant new Rayovac 15 minute system mentioned above. You can get the charger here and the cells here. I'm unsure if the charger includes cells or not and I'm also unsure just how many cells come with the cells ordered alone at those links. It's much more powerful to charge so quickly and therefore is big, heavy, has a fan in it and doesn't run worldwide.

Caveat: 5 years ago Ni-MH was an advanced technology, so the only manufacturers who made them, like Sanyo, made them well. Today all sorts of garbage is out there, and on top of that many makers make bogus claims about capacity (mAh). My 5 year old Sanyos, rated at 1,350 mAh, still give me more service than another brand I was given with "2,300 mAh!!" printed in huge letters. Next time I buy I'll get anything made by Sanyo (who also has made them for Kodak and GE) or Panasonic and possibly Sony. I'd pass on anything lacking the name of a real company on them.

Charging: Ni-MH chargers are usually smart chargers which measure voltage and temperature to stop charging as soon as the batteries are full. Thus they can charge batteries as quickly as an hour or less since there is no worry about overcharging at the fat rate due to the smart charger. As soon as all the charge is put back you stop charging, simple.

Lithium Ion

These are the newest and best rechargeables, since they offer the most power, the smallest size, the lowest weight and require no babying like the Ni-MH and Ni-Cd. They are also the most complex and expensive. They were introduced in laptop computers about 1994 and became common in camcorders and everywhere in the late 1990s. They removed many pounds from each laptop and doubled the run time almost overnight. We would have no iPods or tiny cell phones and microscopic digital cameras today without these. Today every camcorder or digital camera and laptop computer uses these. They only come in special sizes designed specifically for a given piece of equipment and typically cost $30 - 100 to replace.

Care and Use: Completely different from Ni-Cd and Ni-MH, lithiums prefer to be charged early and often. They don't like to be run all the way down. You will get only a few hundred cycles if you run them all the way down each time, and thousands if you charge them up while still mostly full. Lithium Ion's life tends to be measured by how much total energy comes in and out of the battery and not by cycles. Actually you can get more total energy from the battery by only partly using the battery's capacity. Thus I always charge every Lithium Ion battery every night when I've used it the day before, completely unlike the other technology cells. I've gotten great service out of every one I own; I charge my cell phone daily and I've been using it for years.

Chargers: They require very special chargers, unlike Ni-Cd and Ni-MH. Lithium is charged at a fast rate to replace the majority of the charge, and then trickle charged to replace the last 25% or so. Thus you may see charge state indicators which let you know when they are almost done, which happens very fast, and completely done, which takes much longer. Because special charging circuitry is required they are not offered in sizes to replace regular AA or other batteries, since people like me would goof once and blow them up in the wrong charger. Also they don't come in the special 1.5V versions invented by Eveready as a disposable cell, so today you can't get the rechargeable lithiums in AA size.

Brands: Li-Ion batteries require complex charging circuitry and sensors. There are many cheap counterfeit copies out there which skip some safety features. These phonies can and do explode! Because of this I would never buy any non-original brand rechargeable battery to replace any of the specialized batteries in my cameras and computers. Sometimes even legitimate suppliers get stuck with bad parts. See the Nikon recall for instance.

More Li-Ion technical info see Powerpulse and Cardex and here, too.

USE IN ELECTRONIC FLASH

Most applications have a clear winner for what sort of battery is best. Only in some applications, like AA size, do we have so many choices. Here are some comparisons for use in an electronic flash.

(data from Nikon SB600 instructions, typical for most flashes)

	Recycle Time (fresh batteries)	# of Full-Power Flashes
Ni-MH	2.5 s	220
Alkaline	3.5 s	200
Lithium	4.0 s	400
Ni-CD	2.9 s	90

Thus I use Ni-MH. If you don't shoot as much use alkaline. If someone else is paying and you're going overseas by all means just pack a bunch of lithiums.

Ni-MH give shorter recycle times even though they have less mAh than alkaline because Ni-MH have much lower internal impedance. That means they can crank out a lot more amps intermittently than alkalines. Flash uses huge amounts of current for just a few seconds to recycle, thus the Ni-MH can belt it out faster than alkalines. Alkalines are not very happy having to spit out a lot of current all at once, which is what flash needs, unlike a radio. Alkalines don't recycle as fast, but will last for years sitting in an unused flash, while Ni-MH will go dead just sitting there after a couple of months.

RECYCLING

All modern batteries are loaded with powerful, poisonous chemicals and metals.

Actually except for the old carbon-zinc, you ought to recycle every dead battery.

This is easy in the USA. As I recall Radio Shack takes all batteries for recycling, and with more Radio Shacks in the USA than McDonalds (no kidding) it's not hard to find them.

Source : http://www.kenrockwell.com

The Zone System

INTRODUCTION

Zones are levels of light and dark.

A Zone System is a system by which you understand and control every level of light and dark to your best advantage. It works in digital just as it does for sheet film. Having a system allows you to understand and be in control, instead of taking whatever you get. Ansel Adams was asked in the 1950s if he thought the Zone System was still relevant in that then-modern world. He replied "If you don't use the Zone System, then what system will you use to know what you've got as you photograph?"

There are many ways to evaluate what you'll get in your final print or display as you photograph. The Zone System is one way to get a handle on everything. When you know what you're going to get you can make changes as you're photographing to optimize your final prints.

The Zone System applies as much to color, digital and video as it does to black-and-white. Ansel Adams even shows us in The Negative how to use it with point and shoot cameras!

Ansel Adams chose to divide the range between white and black into about ten zones. Each is an f/stop apart. Color film and digital tend to have fewer zones, but that's not important. What's important is understanding how these zones relate to one another and how they change as they go through each step of any photographic process.

From the 1920 through the 1960s The Zone System usually required weird film developing, since people developed sheet film one shot at a time and printed on fixed-contrast papers. It was a pain.

In the 1970s through today the Zone System for film became more involved with printing as people tended to shoot rolls of film that are developed all at once and print on variable contrast paper.

With digital in the 2000s the Zone System focuses more on understanding how digital cameras respond to different levels of light and dark. The Zone System is the basis of understanding PhotoShop's Curves command. With digital cameras you set contrast in-camera, or do as I do and let the camera do this automatically.

The biggest advantage of understanding a Zone System is understanding what's going on. You'll be able to concentrate on making great images instead of worrying about petty things like technique and exposure.

Digital cameras no longer require spot meters. Spot meters were used to evaluate subjects before they were photographed. It was the only way we had to predict exactly how to expose, develop and print before we made an exposure on film. Today we have histograms and LCDs instead. Today I use a digital camera instead of a spot meter to evaluate this better than a spot meter for my view camera!

That said, let me offer that the rest of this page was written in 1999 when I wrote it to apply to color slides.

The Zone System allows you to get the right exposure every time without guessing. It does not require you do any special film development and you never have to waste time with bracketing. Now aren't you interested?

The Zone System is very important to understand, especially for color slides.

Today the Zone System is the careful and analytical setting of exposure. Almost no one does special development for each negative any more.

I learned it all from Ansel Adams' book "The Negative." He covers the Zone System for use with color film and point-and-shoot cameras, too.

Ansel worked in the days when everyone shot sheet film developed individually by hand, and when the only decent papers were fixed contrast.

Therefore of course he suggested screwing with the development of each sheet to print on grade 2.

Today most people shoot color or roll film and variable contrast papers are among the best papers available. Therefore custom development of each image just isn't happening! Today we usually use standard development and vary contrast in printing.

Even Ilford recommends today what I do for color and B/W negatives: ensure you get enough exposure in your shadows, develop your film normally, and then use variable contrast paper for your prints if you need to.

For color one always uses standard development. The colors get very screwed up of you try to vary development times. I have tried with Velvia and guess what: the overall contrast remains almost unchanged with even a plus or minus two stop push or pull! The DMax and shadow level changed, but the contrast of the active image was about the same. Worse, the color balance goes a nasty cyan with a pull. Color takes on a nice warmth with a push, although I only push when I need speed.

Here are my quick suggestions:

METERS much more here

If you are shooting a modern SLR, use your built in meter in Matrix (Nikon) or evaluative (Canon) and forget about most of this. You will need to know when to compensate you meter a bit, but otherwise all Matrix and evaluative systems incorporate the Zone System automatically.

I have a page on how to use the Nikon built-in spot meters here.

If I am shooting a camera with no meter, I use the same meters Ansel did, and you can still buy them today. I use either the Pentax Spotmeter V (analog) or Pentax Digital spotmeters. The digital one is smaller and I use it today as Ansel did at the end. The analog model is more precise and easier to read and interpret, however it is bigger and more delicate. The Pentax meters are superior to the complex, confusing and more expensive Gossen and Sekonic models.

COLOR NEGATIVES

For the color negatives shot by most amateurs just set the camera on automatic and GO! The films today have so much latitude that you just can forget it. Honest, I have tried shooting the same scene at normal and FIVE STOPS overexposed on Fuji 800 and in my prints I can't tell which was which. Never underexpose, that will lead to murky dull shadows. Overexposure by a couple of stops may increase contrast and saturation a little. If color is as important to you as it is to me, unless you print your own work, shoot slides and not prints. See the film page for that info.

B/W NEGATIVES

The same applies as it does for color! Amateurs worry far too much about this. I suggest adding one more stop to your exposure and adding a yellow filter. Try this and be amazed! Details are on my film page starting here.

If you want to get deeper into it, I suggest using your spot meter and setting the darker part of the image to -1 or -2 stops exposure, which is the same as saying Zone IV or Zone III. See more at the bottom of this page, too.

COLOR SLIDES

For now, what you need to know is that if you use anything other than a modern SLR Matrix or evaluative meter, that you need to add or subtract exposure depending on how bright or dark the subject is. Use the spot or center weighted meter and add exposure for light subjects or areas, and subtract for dark ones. SIMPLE!

Here's how much to add or subtract with the center-weight or spot manual meters:

-3 stops (Zone II): Your slide film goes pretty black here. Don't do this unless you want something pretty much completely black. Yes, you can see some detail on Velvia even at -4 stops (Zone I), but good luck trying to print it.

-2 Stops (Zone III): Normal shadows in landscapes are set here. You will use this a lot. This is about as much underexposure you can use and still have detail. For instance, make a spot reading of the shadow and set your camera to underexpose that shadow spot by two stops. If you are lucky everything else will fall into the proper exposure. You don't really need luck: use your spot meter to make sure that at the exposure you set that everything else falls where it ought to per this chart.

-1 Stop (Zone IV): Very few things are set here. This is a dark middle tone, like a red painted barn.

Normal exposure (Zone V): This is where you set middle tones or a gray card. Sometimes the north sky is set to normal (+-0). Oddly, in many scenes there is no middle tone, which is why spot meters usually cannot be used without knowing the zone system. Sometimes green grass falls here.

+1 Stop (Zone VI): Medium light parts of an image. Skin and granite rocks go here. For most landscape photos you'll set your light rocks here, and the shadows at -2 stops. Bright yellow is set at +2/3 stops.

+2 Stops (Zone VII): White things like snow and sheets of white Fome-cor are set here.

+2.7 Stops (Zone VIII): This is where slide film goes clear.

This is how the zones of the classic zone system correspond to the analog bar graph on your exposure meter:

Zone II = -3 stops
Zone III = -2 stops
Zone IV = -1 stop
Zone V = +- 0 stops
Zone VI = +1 stop
Zone VII = +2 stops
Zone VIII = +3 stops

If you are lucky, all the elements in your image will fall within -2 to +2. Usually they won't. Sorry.

If your spot meter tells you that the shadows are darker than -2 stops that simply means they will be fairly black, and if the whites get too much hotter than +2 that they will be completely white or clear.

Slide film usually goes clear at +2.5 stops. It usually starts getting pretty murky at below -2 stops, although you can still see things down to -4 stops on Velvia.

You need to think as a painter does and ask yourself at what level of tone you want each part of your image to render. You need to be in control, and the Zone System lets you be in control. Otherwise you'll simply be gambling that your images will "turn out." With the Zone System you will know when you need to alter your lighting.

Problems

There will be plenty of occasions in nature where God is not putting the light range where you want it. The Zone System is useful here because it tells you before you waste a lot of film that you are probably going to get garbage and thus you can plan or change the light or filtration accordingly.

What do you do if the lightest and darkest parts of the scene are beyond the range of your film, typically +- 2 or 3 stops?

Simple: you have to change the lighting somehow. If you have a very high-contrast scene there is no correct exposure and you will never get what you want.

This is where many amateurs get lost: exposure cannot correct for bad light. OK, nothing can fix bad light. You have to wait for it. Photography takes patience. You can try a graduated Neutral Density filter which often helps bring down an overly bright sky or too dark foreground. Here's an example of one.

Some people try to tweak development to compensate for crummy light. It's much better to fix the light. Ignore the temptation to tweak development; this is why we in Hollywood pull up three trucks of lighting equipment to light a scene outdoors.

If you do your own developing the Zone System gets far more complex if you want to adjust the exposure and development to attempt to fit the range of the scene into the range of the film. This used to be popular in B/W before good variable contrast paper was available, as in Ansel's day. Today B/W shooters make sure that they expose enough for the shadows (make sure everything for which you need detail is exposed at not less than -2 stops) and then use a lower contrast setting for their paper.

If you're asking, no, I have no idea how Ansel got ten zones. Today we only get about seven. OK, actually I do know how he got ten zones: Ansel used less development and slower speeds for his negatives than the manufacturer's ratings. We can't do that with color today. You can do this in B/W, and you have to do a lot of custom testing and developing.

In Ansel's day everyone shot sheet film and used graded paper. Therefore it made sense to develop each sheet differently so it could print on grade 2 paper.

Today people shoot roll film (your Nikon or Mamiya) and need to develop the whole roll the same way. One uses VC (variable contrast) papers to control the contrast, not developing.

You always develop color the same way, unlike B/W. Changing developing times for color often messes up all the color balances.

I have pushed and pulled Velvia and saw little contrast change. The colors shift and the black level changes, but the contrast does not vary as does B/W film.

You have to change the light yourself or wait for God to do it. This is art. Only your heart can tell you what to do. You have to know at what level you want various light and dark areas to render, just as a painter has to decide what colors to take from her palette. There are no written formulae for good photos. Ansel covered this quite well in his books.

Source : http://www.kenrockwell.com

What are LV and EV

LV, Light Value and EV, Exposure Value, are terms used to allow easy discussion of exposure and light without the confusion of the many equivalent combinations shutter speeds and apertures.

LV refers to how bright the subject is. EV is the exposure setting on the camera.

You may have seen them if you like to read the fine print of camera specifications. They are used to specify ranges of light levels for metering and autofocus.

EV and LV follow an open-ended scale. Each one is one stop away from the next. In photography values of about 0 to 18 are commonly used. Negative values are perfectly valid, just very dark and only occur in night photography. LV 15 is full daylight, for example.

Each Exposure Value, or EV, represents any of many different but equivalent combinations of f/stop and shutter speed. For instance, 1/250 at f/8 is EV14, and so is 1/125 at f/11. 1/125 at f/8, one stop more exposure, is EV13, and 1/250 at f/11, one stop less exposure, is EV15. You don't need to remember these, they are on the dial of your exposure meter.

Understanding them will allow you to recognize common lighting values and guess correctly at exposures even without a meter.

This system is the correct way to discuss photographic light and exposure because it avoids all the confusion of f/stops and shutter speeds, if all you really want to discuss is light and exposure levels. it replaces the idiotic question I get all the time while shooting, "what f/stop are you using," which of course means nothing by itself.

LV, or Light Values

An LV, or Light Value, is a number that represents how bright a subject appears in absolute terms. It does not take film speeds or exposure into account. LVs are very handy photographic terms to use to describe lighting levels.

LVs measure light coming from a subject, or "luminance." They are not a measure of how much light is falling on a subject. In other words, the same light falling on a black object will have a lower LV than the same light falling on a white object.

Some light meters, especially spot meters like the wonderful Pentax Digital Spotmeter and analog Pentax Spotmeter V, read directly in LV. You transfer this number to a dial that, along with your film speed, reads out all the combinations of aperture and shutter speed that will give the correct exposure.

Here's a table of common Light Values associated with common situations. If you use one of the Pentax meters you will quickly start to learn these without even needing the meter after a while. This is because the same number pops up for each subject each time. LVs eliminate the confusing issues of film speeds and f/stops that hide these simple truths when using SLRs or other light meters:

LV18 and above: Bright reflection off a sunlit object, including reflections off the sea
LV17 White object in full sunlight
LV16 Light gray object or skin in full sunlight
LV15 Gray card in full sunlight; typical exposure for ugly front-lit noon daylight photos
LV14 Typical light level for side-lit daylight shots in good afternoon light
LV13 Typical shadow cast in a daylight scene; cloudy bright days
LV12 California bright overcast
LV11
LV10 Dark, dreary overcast day in Boston, London or Paris
LV 9
LV 8
LV 7 Typical indoors; light outdoors about 10 minutes after sunset
LV 6
LV 5
LV 4
LV 3 Brightly lit night street scenes
LV 2 Typical night street scenes
LV 1 Dark scenes outdoors at night
LV 0 LV Zero is defined as the light level that requires a 1 second exposure at f/1 with ISO/ASA100 speed film.
LV-1
LV-2
LV-3
LV-4
LV-5 Scene lit by the full moon
LV-15 Scene lit only by starlight. I have loaded sheet film in light this dark, so don't expect to photograph it or meter it.

Some light meters use a similar scale, but shifted by a constant amount. For instance, the Gossen Luna-Pro uses a scale that reads 5 units higher, or reads 20 in full sun. It's still the same concept, and even those meters calculate the same Exposure Values, or EV, once you set your film speed. That brings us to:

EV, or Exposure Value

Exposure Value, or EV, varies from LV, or Light Value, depending on your film speed.

EV = LV at ISO 100

With ISO/ASA 100 speed film you expose with an Exposure Value (EV) equal to the Light Value (LV).

Easy, eh? Your meter will do this for you, but you can do it in your head, too, if you forget your meter. Here's how:

If you shoot slower film you of course have to use more exposure (EV) for the same Light Value (LV), and vice-versa.

The EV is easy to calculate even if you forgot your meter, since each unit is one stop different than the next. For instance, with film a stop slower than ISO/ASA 100 (like 50 speed Velvia) you just subtract one from the LV to get the EV. This adds one stop of exposure.

For instance, if your subject is at LV14, expose at EV13 with ASA 50 film. EV13 gives one stop more exposure than EV14.

With ISO/ASA 400 speed film you add two to the LV to get the EV, which is the same as subtracting two stops of exposure. Therefore with an LV14 subject you expose at EV16.

Remember that the higher numbers refer to higher light values, and therefore less exposure. This is because the exposure values that correspond to those higher numbers give less exposure.

EVs are a great idea: by talking about an EV you are talking about any one of many different combinations of aperture and shutter speed that give the SAME exposure. Cameras started to use these numbers in the 1950s, but today only the Hasselblad retains them. With every other camera one needs to use the scales on light meters to determine the EV values. Some cameras can be adapted, as I did to my Plaubel Makina 67, which simplifies their use with spot meters.

Zero EV is defined as f/1.0 at one second. Therefore, EV0 is a pretty long exposure. This is the same exposure as f/1.4 at 2 seconds, f/2.0 at 4 seconds, f/2.8 at 8 seconds and so on. EV1 is one stop less: f/1.4 at 1 second. EV 2 is two stops less: f/2.0 at 1 second or equivalent EV is a camera setting. It was popular in the 1950s to couple camera controls together so that once one set an EV one could rotate locked f/stop and shutter speed rings to choose between different equivalent settings. Today only Hasselblad continues the tradition. It is much easier to remember typical light conditions as a single EV number than combinations of camera shutter and aperture settings.

So what's the correct exposure for Velvia (ASA/ISO 50) in side-lit daylight? That light is LV14. Since Velvia is one stop slower than 100 we need to give it one more stop exposure, or SUBTRACT one EV from the LV to get the EV. Therefore, LV14 - 1EV= EV13. EV13 is 1/125 at f/8 or 1/15 at f/22. Light meters that read in EV have scales on the side that show you all the equivalent camera settings for any EV.

What tricks does this tell us? Well, in nature nothing gets brighter than something lit by full sun, which is LV15. If you see LV17 in your meter you know that that must be a white object in daylight. Guess what: that's how evaluative and matrix meters know that, too!

Source : http://www.kenrockwell.com

Time Exposures

"T" or "Time" setting

As ought to be obvious, if you are lucky enough to have a camera with a "T" or "Time" setting, use it. In the time setting the shutter opens when you press the shutter release, and stays open until you press the shutter a second time.

To avoid vibration and eliminate the need for a cable release:
1.) Cock the shutter
2.) Cover the lens with something
3.) Press the shutter button to open the shutter
4.) A few seconds later, after any vibration has damped, remove whatever you are holding in front of the lens and start your timer
5.) When you have timed the correct exposure, cover the lens and
6). Press the shutter button a second time

"B" or "Bulb" setting

Most every camera has a "B" or "Bulb" setting. The shutter stays open as long as you hold the shutter button down. It got it's name from the good old days before synchronized flash. One had to open the shutter with one hand, pop off a flash with the other, and then close the shutter. The procedure is almost the same as for the T setting:

To avoid vibration, although you need a cable release:
1.) Cock the shutter
2.) Cover the lens with something
3.) Press and hold the shutter button to open the shutter
4.) If you don't want to have to hold the shutter release the whole time (typically for exposures more than a minute) then lock your cable release in the squeezed position.
4.) A few seconds later, after any vibration has damped, remove whatever you are holding in front of the lens and start your timer
5.) When you have timed the correct exposure, cover the lens and
6). Release the cable release

Nikon SLRs

The hot new SLRs are the worst thing for time exposures.

The best cameras for long exposures are mechanical film cameras. Anything with an electronic shutter becomes a pain depending on how advanced it is. The more advanced, the poorer it usually is for time exposures. The battery in my D200 dies in less than 90 minutes!

If anything is worth photographing with a tripod and a long exposure, it's probably worth photographing with a larger format then 35mm.

The F100 and many AF Nikon cameras are poor choices for making time exposures of longer than 32 seconds.

You are far better off to use an older Nikon camera (or maybe even the new plastic wonder, the N80) with a conventional cable release socket, or ideally use a camera with automatic analog internal exposure control like the FA, FE, FE-2, EM or FA. Those automatic cameras have exposure systems which can measure and make perfect automatic night time exposures for at least several minutes, even though Nikon never specified them to do that. Use the self timer on those cameras in A mode instead of a cable release because 1.) you won't need a cable release and 2.) they have automatic mirror lock-up in this mode, unlike the amateur F100.

If you insist on using your F100 for long exposures as I do, you need to buy a $100 US cable like the Nikon MC-20, hope that your batteries last as long as your exposure, need to set up a complex system correctly, and need to calculate your exposure MANUALLY because the F100 meter does not work in this mode.

You also have to try to thread the dadblasted MC-20 into the camera in the cold and dark and not lose the plastic remote cover in the muck.

The one saving grace to the cable with the timer in it is that it is a joy to be able to program the cable for, say, a 10 minute exposure, and be able to walk away and forget about it while it times itself. I do grudgingly own one of these cables, but as a conscientious objector I bought mine used.

Throw away the battery that comes in the MC-20 cable for two reasons:
1.) It's not needed with the F100; the cable powers from the camera
2.) I've confirmed this: if you leave the battery in the cable and that (unneeded) battery dies while you are in the middle of an exposure, you lose that exposure. With no battery in the cable you are immune to this problem.

Another nicety of the programmable timer cable is that it has a light built-in. OK, that's 2 saving graces.

The F100/MC-20 contraption is difficult to use properly because it is too complicated. You need to:
1.) Remove the plastic cap that covers the remote connector on the F100
2.) Put that cap away someplace you won't lose it
3.) Attach the MC-20 to the F100
4.) Set the cord itself to the correct mode (!) using the mode button
5.) Determine your exposure time manually (The F100 meter does not work in this mode)
6.) Set the exposure time on the MC-20 using about four different buttons
7.) Set the F100 to MANUAL exposure mode
8.) Set the F100 exposure time to Bulb (!)
If you forget to set all those modes on the F100 and the MC-20, you ruin your image because they do not communicate with each other to let the F100 know that the cord is connected for a time exposure. If you leave the F100 in any other exposure mode, or set the exposure time to anything other than Bulb, it totally ignores the time set on the MC-20 and just does whatever it would have done without the MC-20 attached, wasting your film.

A better way to spend the same $100 you'll have to spend on that atrocious MC cord is to buy a Nikon EM for $75, sell the 50mm lens that came with it for $25, and take the $50 you have left over and buy some more film. You can use the EM in mechanical manual Bulb mode for your time exposures and not have to worry about batteries. Even better, the Nikon EM has analog aperture-priority automation, which means that it makes long automated time exposures much longer than the one second Nikon specifies. The EM makes perfectly timed, automatically exposed time-exposures out to at least a few minutes. With the F100 you need to use an external meter or calculate in your head to determine the correct time to expose the hard way. I've tried this, and the EM is far better than my F100 for night photography. You can set the EM to a nice aperture like f/8, set the self timer, and walk away while the EM does a great job. The EM also has a virtual mirror lock-up (like a professional camera), unlike the F100 which does not. The EM also has a metal back and metal rewind fork, unlike the amateur plastic rewind fork fiasco of the F100.

Yes, the EM is usually poked fun of because it was a dinky camera compared to its siblings, the F2 and FE of the 1980s. Because less experienced photographers of today poo-poo it, you can get one for almost nothing and have a fantastic camera for night shooting that's far better than the F100. The EM has a lot of mirror slap making it a poor camera for daytime shooting. The FE, FE2 and FA are superb for everything but will cost you about $300 US used. The EM does not use its battery for BULB mode, but you will want to use it in A mode so it times and measures your exposures. The EM only draws 13.5 mA from it's S76 cells while the shutter is open, so you ought to get about ten hours of exposure time from a set. You only get a couple of hours out of the F100.

Source : http://www.kenrockwell.com

Lighting

Lighting is the most important technical aspect of any photograph. Cameras, lenses, and everything else are completely irrelevant unless you have good enough light to make a good photo.

No amount of Photoshop or plug-in software filters can replicate good light.

No amount of Hollywood special effects can change the lighting if it wasn't there to begin with, unless you repaint each and every pixel the hard way.

How do we get great light in Hollywood? We make it with three trucks of generators and lighting equipment. That's all the junk you see on a movie set: it's all the lights, scrims, gobos and supports for it all. Half the names you read in the credits are the guys who have to rig all this up. All that lighting is there to make everything look natural, as if there was no artificial lighting used at all. The camera itself is tiny by comparison.

When you shoot in a studio, or shoot smaller subjects like people outdoors, you can bring your own lighting. When it comes to photographing mountains, you're probably going to have to take whatever light you're dealt by God and nature. Most of my discussion refers to natural light; in a studio, its far more complex. In all cases, you follow your eye to highlight what you want, and downplay what you don't.

When you work in nature and don't have a $10,000,000 budget to create your own lighting, you have to wait for nature to do its thing.

No matter how expensive your camera, lighting is everything, so if you don't have spectacular light, you won't get spectacular images.

Source : http://kenrockwell.com

Composition

Composition is the pleasant arrangement of elements within a frame.

Edward Weston said it best: "Composition is the strongest way of seeing." You need to organize your stuff so it makes sense to every disconnected viewer, otherwise your photos will stink.

Framing is how you drop the photo's edges onto your composition. It's controlled by where you point your camera and your lens' focal length.

Perspective is the location of your camera. Perspective is defined by where you stand and at what height you hold your camera. Perspective doesn't change as you zoom. Perspective only changes as you walk around and raise and lower your camera. Tripod users cripple themselves because all too often they shoot every picture at the same height, which is rarely the best height.

Composition is when your girlfriend comes over and straightens up all your magazines, cameras, half disassembled motorcycle engines, shoes, books, dirty socks and sporting goods that you left all over the house.

All this junk makes perfect sense to you or me, but it makes no sense to the woman or anyone else who comes over. You or I know exactly why and where everything is, but it makes no sense to anyone else. The woman needs to organize it so she can understand it and so it looks pretty to her.

This is composition, and most men hate it. I know I sure do. That's why our photos usually suck.

Like a dirty room, your photos always make sense to you, but they won't make sense to anyone else unless you clean them up first.

A photo needs to make sense instantly to anyone who looks at it. No one is going to try to figure out your photo any more than anyone would try to figure out why you've got dirty shirts thrown in three random piles. No one cares about your piles, and no one will care about your photos unless you expend conscious effort to tidy them up.

All too many hobbyists worry about every technical and equipment issue, but never bother organizing what's in their photos as the snap them.

Camera catalogs, just like furniture stores, like to lull you into thinking that all you have to do is buy the camera (or furniture), and everything will magically clean itself up for you.

Most people set up in the most convenient spot and shoot away. We'll zoom in and out and look left and right, but that's it. We figure we always can fine-tune things later in Photoshop or Lightroom. Just like our living rooms, we know we can clean them up later.

NO!!!!!!!!!!!!!!!!!!!

You can clean up your bedroom next week, but you can't fix composition after the shutter closes. Photoshop can make things lighter or darker or crop out junk on the sides, but it's a real bear to try to move objects around within a frame. You can move objects if you extract them and put them into separate layers, but you never can move shadows or light sources unless you start redrawing pixel-by-pixel.

Guess what? I've worked in Hollywood where we do these things to images in post production every day, but the only way we can move light sources is by reshooting, or by re-rendering CG (computer-generated elements) after we've updated the coefficients that describe the light sources.

The only way to ensure strong composition is to look through your finder and make it that way before you press the shutter.

Move yourself around to change perspective, which moves elements around in your frame. You can change the relative sizes of elements by moving in and zooming out to maintain the same framing. When you do, closer elements just got bigger while distant ones just got smaller. This is the real reason to use zooms: because you have precise control over the relative sizes of objects so you can create perfect balance.

Move the objects around yourself if you can. Have your model move here or there, push the props around, and have people do what you need them to, because it's usually impossible to change it later.

Composition is just like arranging stuff in your house. Some people have a knack for it, like women, while we men usually just make it practical. Some people have a natural talent to make things look right, while most people don't. I know I sure don't; before I was married, my place was a dump.

I have to work really hard to make my photos work. It has everything to do with conscious composition, and nothing to do with dumb luck.

Photographic composition is just like interior design. Each places elements in a space: the designer arranges your room, while you have to design the elements in your frame.

Does this require practice and careful study? Yes! Some people just have the knack, while most people don't.

Painters need to dream all this up in their heads. Painting is tough.

Photographers have it easy: we can move around and hopefully recognize when things look right in our finders.

If you shoot by pointing your camera and zooming in and out, that's why your photos are dull, regardless of how expensive your camera gear. Your photos are probably as messy as was your dorm room.

Just like the stuff in your house, a photo only looks good to other people when you've gone through the conscious process of arranging (composing) everything to make the clearest, strongest statement that you can.

Your photo can't be like a messy room. A good photo has everything arranged perfectly so that when someone sees it for the first time, everything is obvious and there are no distracting elements.

I hate it when strangers send me crappy, carelessly composed photos and ask me "are these any good?" The key word is careless: the shooter never paid any attention before he shot. No one cares if they're sharp and well exposed (every camera does that automatically today), what's important is what effort did you put into composing the picture.

I always find something nice to say because that's the way I am, even though I'm usually thinking "What a careless idiot. Why would he think anyone else cares about this photo if he didn't care about it when he snapped it in the first place? What is this photo supposed to mean? What am I, a mind reader?"

For the particularly dense, when I say I'm not a mind reader, I mean that of course I know you've sent me a snapshot of a cat or a kid or a sunset. So? Why should I care? When I say "what does it mean," I mean does it show glee? Elation? Does it make me laugh? Does it make me soil my own pants over how beautiful it is?

What makes the photo stand out or make it beautiful? Is there a funny gesture? Does the cat have a $500 bill in its mouth? Are you showing me a unique point of view I haven't seen before? Is there a punchline (funny ending) someplace?

Ask yourself: what about the photo makes it worthwhile for anyone else to spend the time examining? If there isn't anything, then it's just another crappy snapshot. Digital will do this to people; that's why there's a delete button. Use it.

Good photos reward viewers. Crappy photos without rewards waste people's time.

If you shoot and don't really know why, your photos probably fall into this class. As Galen Rowell observed, careless shooters will usually come up with an OK shot every so often by pure luck, but the only way to create consistently good work is to pay attention.

Pay attention to what? That's why you go to art school, and why most of the world's best photographers have arts degrees, like Cartier-Bresson, Jay Maisel, Ansel Adams, and the list goes on and on. The best class you can take to improve your photography is to take a local adult-ed or community college class in drawing, painting or composition. It's often free, or might cost as much as a whopping $80.

In a nutshell, composition is all about balance. It's all about balance between light and dark, warm and cool, big and small, rhythm, pattern, line, curves, impact, negative space, texture and a lot more.

Composition also deals with how a viewer's eye enters and explores the image. Our eyes are first attracted to the lightest or most contrasty areas, and explore out from there. Don't give the eye any lines that lead it out of the image; you never want to break the frame. Darken the edge of the frame if a line might lead an eye out, but remember that lines also can lead eyes in. We Americans read from left to right; other cultures read differently. You want to keep viewer's eyes from wandering out of the picture. Darkening the edges and lightening your intended points of interest help.

Pay rapt attention to your composition while shooting. Forget tech while you're shooting. I may obsess about tech all day while writing this website, but when I shoot, I think about nothing technical at all.

The only reason to pay any attention to technical issues is so that you've so mastered them that they are unconscious second nature when you're out shooting.

All I'm doing when shooting is concentrating on how things layout and balance in my finder. I'm even trying to defocus my eyes so I see the critical underlying fundamentals of the image, without the distracting details.

Good composition happens in the subconscious basics that underlie an image. The strong fundamentals of light, dark and color that we see even as a thumbnail image are the most critical things.

Sharpness has little to no bearing on composition, and therefore has little to do with the value of an image. Sharpness is a distraction that diverts our attention away from the fundamental elements which are the foundation of a strong image.

I'll say that again: the most important parts of every image are the things that are visible even as a tiny thumbnail. These are the overall organization, weight and balance of every image. If you can't get an image to look good as a thumbnail, it's not a strong image.

Concentrate on the thumbnail as you compose. Tiny finders aren't much fun, but they help us see the basics better. Big finders are bad because they make it more difficult to see the basics: we see the leaves on the trees instead of the overall composition of an image.

Large format cameras have upside-down images, which are great because they further abstract the image from the present reality, and force the photographer to create a composition with strong basics that stand up regardless of the details.

Ask any painter: often they'll invert their canvas to see if the composition holds up when the conscious subject matter goes away.

Focus on the fundamentals of your composition, not the details of your subject or technology. Be certain that every image makes sense to anyone who sees it, not just to you.

Composition is everything in a photo. The basics of color and shape are critical. The actual subject matter is only secondary or tertiary. Art critics tend to categorize me as a toilet photographer, but in fact, my work is all about the colors, shapes and relationships. Toilets just happen to pop into my viewfinder becaue I usually have to pee after being out shooting, but they aren't the subject: it's their shapes and colors.

Source : http://kenrockwell.com