Sometimes we end up with a great image only to realise that the whites are blown to smithereens. And no matter how hard we try to put things right in post production we can never recover the lost detail. And although it’s generally not possible to recover blown white detail in editing there is a lesson to be learned for future reference.
So let’s have a think about this for a moment and consider where the root of the problem lies.
Here’s a question…how often do you take a test shot and check your histogram? I suspect not too often. And herein lies the issue. So many ‘togs think that under exposing and image in order to pull-out white detail is the answer…and you can get away with it sometimes, especially if your camera handles noise well. However, the truth of the matter is that the left side of the histogram contains far less data than the right side. Common sense, therefore, should tell us that underexposing an image (in an attempt to pull-back white detail in post – yes, I know you can apply masks/layers but why make life unnecessarily difficult) will make it far harder to recover shadow detail without noise creeping in. Result: an imbalance in the final tonal range of the image. And most probably a completely unrealistic representation of true colour. But there is a much better and much more accurate way to create a correctly exposed image with detail in both shadows and whites. It’s simply a question of spot metering correctly…
First off we must remember that there is absolutely nothing we can do about specular highlights apart from waiting for the light to change. But we can ensure we get white with detail in a well exposed image IN CAMERA. It’s simply about putting just one part of the image in the correct place on the histogram. And if we put just one part of the image in the correct place then every other part of the image will also be in the right place. We do this by spot metering. Let me explain:
Suppose we’re photographing an animal in bright/good light that has white feather/fur somewhere on its body. If we meter with any pattern other than spot then chances are the white detail will be lost forever. But if we use spot metering we solve the problem. This is how it works:
Spot meter the white detail area, lock the exposure, add a couple of stops (and recompose if you wish) and take the shot. Job done! The whites will be perfectly exposed showing detail without affecting the shadow detail. So what’s happened?
Whatever we spot meter is ‘made‘ a mid-tone (18% grey) and sits at zero on the histogram. White with detail sits approx +2 stops on the histogram. So if we initially spot meter the area of white detail we know it’s going to sit at zero on the histogram and it’s going to look grey rather than white. So we need to make it white with detail. Having locked the exposure with white at zero we simply add two stops because +2 on the histogram equates to white with detail. Therefore, if we’ve correctly exposed for white with detail and put it in the right place on the histogram then everything else in the image will also be in the right place on the histogram.
You may say that the animal you want to photograph is too far away to accurately spot-meter and so there’s nothing you can do to ensure you get the desired result of white with detail. Well there is…it’s called substitute metering. But more of that in another post.
Try it. Practice. And never look back.
Happy snappin’ folks
Meter The Light 