#14 in the Judging a Photograph Series
In spring it’s not unusual to get quick changes in weather blowing in across the sky. I love good clouds in an image. You might dream of days with clear blue skies and strong sun but this doesn’t make interesting photographs. In the day time the sky is always going to be a very bright part of a photograph so to expose it well, you have to make a decision. Is it going to be a photo mainly of the sky, or is it going to be a photo of something else with a bit of sky in it?
Let’s say I have decided I want to record a beautiful, cloudy but very bright sky in the landscape. If the sun is out then I have the challenge of high contrast. The brightest part of the photo will be an awful lot brighter than the darker part of the photo. There are limits to what a camera can record and in very high contrast conditions there will be too much pure black or pure white in the photo.
When I took this photo of the Solway Firth I liked the shape of the coastline and the light on the water. Even more than that I liked the clouds and the quick changing sky. The sun was right ahead of me behind the clouds. The bright bits were so incredibly bright! Getting the right exposure is very difficult on a day like this. It’s very easy to get everything washed out with too much light.
To get round this, I under-expose the photo, knowing that I can fix it when editing. The before and after versions of the photo are both here to see.
In the final version I’ve kept the high contrast effect and the little bit of distant land is almost black which I don’t mind.
Brace yourself, here comes the science bit!
Digital photos can often be rescued from a bit of under-exposure. Once a portion of a digital image is over-exposed, the pixels register pure white (aka “blown out”). There is no coming back from that. The data in the pixel only has white information in it; it’s blown the data limit and is saturated. However in an under-exposed pixel, there is better data. If a pixel has been exposed at all (as it will have done, if you released the shutter) then it’s unlikely to still be true black. You can perhaps draw this information out in an editing programme. This is particularly true if you have shot RAW rather than JPEG because they store much more data.
In a nutshell – you can bring down the brightness in only some darker parts of an over-exposed picture, BUT you can turn up the brightness in nearly ALL of an under-exposed picture. So if in doubt, under-expose a little.
Lastly, a tip
Do actually adjust the brightness in your photos before publishing or printing. Don’t be afraid to try this if you think it needs it. Every editing app has brightness adjustment.
Did you know this information about how under and over-exposure work before? Or is it news to you? Let me know in the comments.
Read the previous blog in the Judging a Photograph series by clicking here.
Read the Judging a Photograph series from the start by clicking here.