Now that you know how to use your histogram, lets look at another quick tip that goes along with it. If you see that a portion of your image is clipped, you may wonder how to know exactly what part of the image is blow out completely (overexposed), or which part is far too dark (underexposed). Most cameras now have a way to let you know right upon the image review.
The highlight and shadow warnings, often called “blinkies”, are an awesome tool to go along with the histogram. When they are turned on, your image will blink on all of the pixels that are either completely blown out, or completely in shadow. Some cameras will blink red for overexposure, and blue for underexposure. My Sony a6300 blinks black on the highlights and white on the shadows, so each camera may be a little different.
Use the blinkies in combination with your histogram to track down exactly where your image needs work. If you notice any blinkies on your image at all, you know you’re going to have clipping on the histogram. The good news is, that instead of just guessing whats getting clipped, the blinkies are there to show you. If the rest of the exposure is right on the money but you’re clipping out a tiny bit of a highlight somewhere, or a light in a room, you may be perfectly okay with that and not need to correct the exposure. But, if your getting a shadow warning on someones hair for example, well, you’ll likely want to reshoot that one with a little bit brighter exposure as to not make their hair look like a giant black blob on their head.
The biggest thing though is to use it with the histogram to determine exactly what pixels are clipping so that you can determine how important those parts of your image are. Obviously the goal is to not have any blinkies at all, or no clipping on the histogram, but certain scenes just have too much dynamic range to avoid it. Sometimes there just isn’t much you can do about it in a single exposure. But the good news is that you can adjust your exposure accordingly based on the actual pixels that are over/underexposed.
In most cameras the setting will be called something along the lines of highlight/shadow warning. Also, as a side note, you can enable the same feature in Lightroom when editing so that you can adjust your images perfectly without losing detail to highlights or shadows!