I bought the Sony A7 camera recently and have been taking it out quite a bit to get a feel for it.
My wife is starting a fashion blog so I thought I would take her out for a fashion shoot at the beach. I was shooting a high-contrast scene and realized. . .
The camera doesn’t always know what’s best
Your camera always has the best intentions, but it doesn’t always get it right. Sometimes the sensor will think you want to expose a scene one way when you actually want it to expose it another.
I’ll show you an example. I put the camera on aperture priority and shot this:
To most people, this image would be considered underexposed because the model is dark. This happens because the scene has a lot of contrast. In other words, there is a lot of bright pixels (the sky) and a lot of dark pixels (the rocks, ground, and model).
Why doesn’t the camera always get the exposure correct?
The camera sensor is trying to create an average of dark pixels to light pixels. The histogram shows the dark pixels on the left of the graph and the bright pixels on the right.
A “properly exposed” photo means the balance between the blacks and whites is mostly even. The graph isn’t pushed into the left wall which would be very underexposed, or pushed into the right wall which would be very overexposed. The problem is that to expose properly for the model we need more bright pixels, we need to increase the exposure. Sometimes you will need to trick the camera to get a good exposure.
Using exposure compensation
Sometimes you just need a little bit more or a little bit less. In this case I had the ISO and the aperture exactly where I wanted them. I had my camera set up so the front dial controls the exposure compensation.
In this case, exposure compensation is set up to slightly change the shutter speed to either increase or decrease the exposure. I twisted the exposure compensation dial until the image looked good which was a shutter speed of 1/200.
This looks much better. The model is properly exposed now but the sky is now overexposed. Because the sky is now white, you can see the histogram is pushed to the far right.
This typically means the image is overexposed but in this case it’s simply because the sky has a lot of white pixels in it that register on the right of the histogram. Let’s see it in another example:
I just used the exposure compensation to bump up the exposure again so the model was properly exposed and the sky was overexposed in the image on the right.