Tip of the week: Adjusting exposure in post processing

Very common mistake that is most likely to happen if you are still in the learning process of taking photos is underexposure or overexposure of the photo. Images that have blown highlights, or lack details in shadows and dark areas are not so pleasing to the eye and usually don’t have sales potential in stock photography.

Man in despair, sad and lonely standing in front of a mirror

Don’t get me wrong, there are cases when under or overexposure is done in a way so that the image carries certain message or tells certain story. People usually connect bright images and vivid colors with positive emotions and happiness, and thus darker tones with sorrow, sadness, or something not so positive. That is why photographers sometimes express their message using exposure values. Usually, if we deliberately overexpose, we are creating image called "High key", and if we underexpose we get the "Low-key" photograph.

Young familly on the bed

The problem starts if the image which should have normal, proper exposure gets underexposed or overexposed. In that case we need to correct the exposure in post processing if we failed to create proper exposed image in the camera. Every image processing software nowadays has the option to correct exposure. Usually, there is a slider called „Exposure" which you can move to the left or right and correct this problem, but… its not that easy as it seems to be.

If you correct the exposure for a small amount, usually you will get good results, but if you missed the exposure a bit more, some problems will occur.

Case 1: Overexposed image or blown highlights

Problem: Correcting overexposed image is usually much harder than underexposed image. Usually there is not enough data in white overexposed areas to recover. So moving the slider gets you nowhere except getting some banding and some changed colors. Especially if your photo was saved in JPEG format in the camera.

Solution 1: Use RAW format that records more information than JPEG and move the „Exposure" slider to the left. In this way you can correct this problem usually for up to one stop of overexposure. How much you can recover depends also on the quality of the sensor in your camera.

Solution 2: If only the bright areas of the photo are overexposed, you can try and use the slider called „Highlights" which corrects only bright areas and leaves midtones and shadows almost untouched.

Case 2: Underexposed image

Problem: Although this is much easier to correct because camera records more data in the dark areas than in highlights, you can still encounter problems such as increased noise in the recovered areas, or banding.

Solution 1: Use RAW format again and move the „Exposure“ slider to the right.

Solution 2: If only dark areas need to be brightened, use the slider usually called „Shadows“. It increases exposure only for the dark areas, but if used extensively can also lead to increased noise and artifacts.

Lighthouse in Ahtopol, Bulgaria

There is something called dynamic range. Simply said, it is the ability of the camera sensor to record the most darkest and brightest part of the image without saving them as pure black or pure white. The more dynamic range the camera has, the more information you can recover from the darkest and brightest areas. Cameras with larger sensor usually have more dynamic range, so you should know your camera and learn what your camera can and cannot do.

The most effective solution to this problem is to set the camera to expose correctly before taking a photo. In this way you will not lose almost anything in post processing and you will just deal with small exposure corrections if needed. If you usually post process your images, it is best to set the camera to record in RAW format. It does take more space on the memory card, but also saves much more information in the photo and you will have more freedom in post processing. Also, do not over process the image. If the exposure is missed by a long shot, it is better to take the photo again if possible, than to have an image which looks bad and over processed. Just ask yourself, if you were the buyer, would you buy such image at all?

Photo credits: Boggy, Marina Pokupcic, Milan Ljubisavljević.

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June 11, 2019

Milanlj

thank you :)

December 03, 2018

Aurelielemoigne

Very useful, thank you !

November 23, 2018

Viocara

Useful! Thank You Milan!

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