Steve's Photography Tips: About Exposure

Most all of the Photography Tips posts so far have mentioned “exposure” to some degree without always making clear exactly what that is. Having a good understanding of exposure will help you to take better photos because after all exposure is what it is all about. And if you didn’t want to take better photos, you probably wouldn’t be reading Photography Tips posts, would you? I didn’t think so.

Strictly speaking, exposure is the amount of light that passes through the camera lens to either the film (in film cameras) or the imaging sensor (in digital cameras). And the previous posts have talked about how this amount of light is controlled by setting the shutter speed, aperture, and ISO using the various shooting modes on your camera. This isn’t to be confused with an exposure, which is the same thing as an image. Same word, but two different meanings. So you need to have the right exposure for your exposure to get the most exposure for your photographs. Clear as mud, right?

So when we talk about a photo having the right exposure, we usually mean a balanced image where you can make out the main details of the photo, or in other words that the photo isn’t too light or too dark. If a photo is too light, it is referred to as overexposed, meaning that too much light was allowed through the camera. And conversely (which has nothing to do with tennis shoes, by the way), an underexposed photo would be considered too dark because not enough light passed through the camera.

Exposure measurement is often referred to in terms of Exposure Value, or EV, and each increment of 1 EV is known as a stop. And not to confuse you any, but your camera probably has an Exposure Compensation meter, with readings such as -2, -1, 0, +1, +2, and maybe some points in between. With this meter, 0 is what the camera considers to be a “normal” exposure. Settings of +1 and +2 and so on mean one or two stops above, and also -1 and -2 mean one or two stops above. Going along with the previous paragraphs, an underexposed photo would be in the negative range, while an overexposed photo would be in the positive range. The camera aims to arrange the settings (or helps you to arrange the settings if you are setting some of them yourself) so that the meter reads 0.

Okay, enough with the wordy mess, how about some photos? Here is a photo from one of our beach trips:

This one was what the camera considered to be normal, which is a bit tricky with the sun in the frame (don’t stare into the sun, by the way, and be careful shooting into the sun, because it could harm your camera’s sensor).

Except for the sun, this next photo above looks to be a bit dark, doesn’t it? This one is underexposed, and was actually shot at -2 on the camera’s Exposure Compensation meter.

This last photo is overexposed, at +2. And as you can see it looks way too bright, except maybe for some of the detail in the umbrella and the chairs.

Of course, overexposed and underexposed photos aren’t always bad. Sometimes you need to overexpose the photo, especially if the foreground subject is darker than the background. Or sometimes you need to underexpose a photo because the foreground subject is too bright when compared to the background. Or sometimes, you can put all of those elements together to form one photo, such as this:

Combining those exposures produces what is known as a High Dynamic Range, or HDR, image, which combines the best of all the different exposures into one photo. But more about that another time.

While your camera may be pretty smart, sometimes you have to outsmart it and change the exposure settings yourself to suit what you are shooting. Take for example this photo of Laura and our horse Bubba:

Because the sun was coming in from behind them, I had to turn up the exposure compensation so that the photo would be “brighter,” even though the camera was telling me it was too bright. Yes, the sky is washed out a bit in the background, but the nice blue sky wasn’t what I was trying to capture in this photo. If I had let the camera do its thing, Bubba would have just been a black horse-shaped blob instead of having good texture in his fur and mane. And Laura would have looked too dark, too. This is one of those examples of what I was meaning earlier when an overexposed photo is not a bad thing. Because to you and me, this photo isn’t actually overexposed, no matter what the camera might be trying to tell you.

Here is another example, this time in the other direction:

This time around, the lantern in the foreground was much brighter than the rest of the Polynesian Village Resort in the background, so that I had to dial down the Exposure Compensation to be able to get all the detail that I wanted in the lantern. That makes the background slightly darker than it would be in a photo that just focused on the buildings, but it also makes the lantern stand out from the darker background more.

For most cameras these days, changing the Exposure Compensation is really easy, and it usually involves either turning a small dial or pushing a button one way or the other, depending on which direction you want to go. As I have mentioned before, this would be another good time to actually read your camera’s dreaded manual to find out exactly how that works with what you have.

So as you can see, there isn’t one right value for exposure, even though your camera may tell you so. If you think you know better than your camera, then don’t be afraid to change the settings for what you think is correct. And especially if you are shooting something important, take a few different photos, changing the settings each time. That is much easier and cheaper to do with today’s digital cameras, and you will probably be glad you did it in the long run.

And as I have said before, the best thing to do is to go out and experiment when you can before you are taking photos of something that you really want to get right, just to give you a bit more confidence about what you are doing. Because just like in sports, playing the piano, riding a bicycle, or anything else, you only get better by practicing!

Be sure to check out other Photography Tips, and check back soon for more!