Tech Tip - Exposure Compensation.

Exposure Compensation. What is it and when would we use it?

What - The ability to have the camera pick what it thinks is the correct exposure then telling it to adjust it lighter or darker by a determined amount.

When and why - Today's camera meters are pretty good at getting your exposure correct but they are still fooled by bright scenes like snow, sand or even lots of grass or dark scenes with lots of blacks or night scenes. In these situations, it will over or under expose your images. If you are after a certain lighting such as dark night with just the street lights lighting the scene, the camera will probably over expose the scene and wash out all the nice dark areas. Using exposure compensation you can compensate for the built in meter.

Keep in mind though this is only for use in one of the priority modes. Either shutter priority or aperture priority. It will not work in manual. But if you are in manual, you may still want to think about what the little needle on the meter is telling you is correct exposure. It still thinks the same way.

Now, how do we go about doing this? Well as for the physical way to compensate please refer to your camera's manual. Now as for the effects of it and when to use it, read on.

Shooting in brightly lit scenes such as snow, sand and even fields of grass. Let's use snow for an example. It's winter here in Edmonton and we have lots of the white stuff.

In this first photo, I placed a pop can on some nice white snow. But the camera tried to make everything a nice middle gray. It succeeded. Everything is gray. The camera set the exposure at 1/400 sec with my aperture of f/5.6 and ISO 100. Under exposed and made the snow look gray.

In the next photo, I set my camera's exposure compensation at +1 stop. The snow is much brighter and whiter. I could have gone another 1/2 or 2/3 stop brighter but I think you get the idea. It was hard to tell outside in the bright light if I got it right. I can bring it up a bit in post if I wish. The camera set the shutter speed at 1/200 sec for this with the same aperture and ISO as the previous example.

Now for the other direction.

In this photo the camera set the shutter speed at 1/15 sec with my aperture of f/5.6 and ISO 400. The seat is a bit to bright for my liking.

So I compensated down 1 stop. Which adjusted the shutter speed to 1/25 sec with my aperture and ISO the same as the above example. It darkened down the seat enough but did not affect the apple too much.

The apple is not really the best example. I would use this technique when shooting in a low light environment that I wanted to keep the exposure darker. Such as a dark room light by a fireplace that I wanted to keep the feel of the scene.

I hope this helps clear up the exposure compensation feature on these amazing DSLRs we have at our disposal.

Chris.