Post edited 1:09 am – January 13, 2010 by DrZoidberg

Unless you have some sort of magical exposure calculator in your head, you'll need a light meter to properly expose your stuff. Although most modern cameras have a meter built-in, some of us are still using 50 year old stuff that doesn't even have batteries (and so doesn't have a meter). Even if you just bought a new digital camera, a handheld meter is always a good thing to have. In this article we will be covering: handheld meters and incident and reflected metering, in-camera metering and modes, and why your meter doesn't always tell the truth.

A handheld meter is a meter that is seperate from you camera, and so won't be telling your camera what to do. This is where manual mode comes in. I use this, a sekonic L208. It fits in my pocket and does the job without  all the fancy lasers and buttons. It has incident and reflected modes. Some also have spot, which will be covered in the in camera part and does the same thing.

Bascially, you press the button on the right and the green arrow moves, then you line up the orange arrow with the green arrow. All possible combinations (most of them anyway) of shutter speed and aperture are shown. I don't know how digital meter works, but it will eventually return the same results. This meter has two modes, called incident and reflected, which are controlled by the white dome at the top of the meter. When the dome covers the sensor, you're using incident and when it's not you're using reflected. Most meters I've seen have this, and incident usually operates like that.

Incident metering is done by taking the reading from you subjects postion, pointing the sensor at your lens. It is usually more acurate than reflected because it is not as easily tricked by very reflective objects. The dome over the sensor helps filter out excess light that may be reflected by an object (think snow) and get a proper reading. For example, this picture was exposed on velvia 100 (slide film, less exposure latitude) with incident.

The meter was put under the same lighting condition as what I wanted to expose for (trees, skier) and not in direct sunlight. That would make it too dark. The incident meter tells you the amount of light that's hitting your subject, not the amount it is reflecting. In contrast, had I just used all area in the camera without considering all the snow, the trees and skier would be dark and the snow would be exposed properly, which is not what I was going for. I use this way more than reflected, on the hill, at the beach and pretty much everywhere. Here's another shot with incident, anything else without adjustment may have truned out different. Ahhhhh, summer!

This is one of those shots where everything seemed to reflect the same amount of light because of the strong sun behind the camera. That's why everything has detail and I'd venture and say reflected or an in camera meter would have gotten this one right.

Reflected metering tells you how much light your subject is reflecting, duh. In the above picture this mode would have been fooled by the snow and gave me an underexposure of the image. On a handheld you point the meter at you subject, preferably from near you camera. The dome must be off the sensor. If you can't approach your subject this is the method for you, think tigers or a distant snowy landscape. While using reflected you'll want to consider what you're aiming at. Since you know that snow reflects a lot of light you need to compensate for it and slow your shutter or open up the aperture a little.  That landscape with awesome trees may not look good with dark blue snow and all black trees in it. Also consider your subject, a neon colored rider or skier may reflect nearly as much light as the snow. You'll probably want to use this if your subject is emitting light, but always consider other elements in the scene.

In-camera metering is obviously done by your camera with it's own meter. My Canon t90 (part of the fd manual focus system) has Center weighted average, 13% spot and spot metering modes. Yours may have more since that thing is several years old now.

Center weighted average or any form of average metering takes the whole scene into account and is easily confused by snow most times. Again, the above image would probably be under if I used this. It measures how much light is being reflected into the lens. 

13% spot is a more precise mode that meters a circle in my viewfinder that's supposed to be about 13% of the total picture area. It may be know as other names, but the idea is that it's more precise than an all area metering pattern. I used it here by metering off the tree bark to the left side. This was on superia 400, cheap but good. This is form nearly the same spot as the skier one  only a few minutes apart.

Spot metering, may be called fine spot or something like that on other cameras, is supposed to be about 2% of the image on my camera. It's very precise and selective. I use it when shooting people and other scenes when the subject is surrounded by very different lighting. It would have also worked in the above, and I used it to meter the wlf (the viewfinder) of my yashicamat in this photo. Any other form would have been confused by the snow or black camera. It also measures the reflected light, which was necessary since the wlf emits light. Incident just wouldn't work here.

Just be careful what you point it at. If you point it at an extreme (something very dark or bright) your whole image may turn out wrong.

Well, that's really it, and remember that it can be more complex if you want, but I kinda told it the easy way here. Just remember, the meter is like a calculator. Like my math teacher always said: "the calculator isn't wrong, you're wrong" when kids put stuff into it wrong. It can be tricked and fooled easily and it's up to you to decide whether the data makes sense. If it it says 10 seconds at f2.8 and your shooting your friend on the 50 footer you know something is wrong (unless it's night and dark). I don't know anything about using a meter for flashes, but post questions about anything here, somebody else may. Also, if you think any of my info is wrong, tell me, I'm not an expert.

Tips/sparknotes

Incident is harder to fool but it can be done, and you have to aim at your lens from where you subject is.

Don't use incident when your subject is emitting light.

Reflected as well as any all area in camera modes are more easily fooled by snow, sky and water.

Snow reflects a lot of light and can illumniate a skier or snowboarder, like a giant natural reflector. I've noticed this mostly in powder shots. When a rider is knee deep in snow wearing a bright orange jacket they can't be too far off in reflected light values. Meter the rider and the snow won't be far behind.

Use your head, think about the numbers before pulling the shutter.

Don't expose for snow, especially in black and white. Most of the time you want it white and nobody likes an underexposed image with gray snow.

A quick note about ninja riders aka somebody in all black. As you can tell from the skier picture black reflects little light, if any. That's why his coat is a black blob.  It's pretty hard to expose for a ninja rider without flashes or great natural light, so go for the silloutte (did I spell that right?) Metering off him and then shooting will give a way over exposed scene. Incident is your friend here.

Now get out there and shoot some properly exposed photos.