It’s a little understood fact that when relying on your histogram to take photographs, or using your blinkies for highlight warnings (among other on screen information based on your exposure), the histogram is based on the jpeg profile that you are currently taking photographs in, and not in the raw image produced by the camera. This article will take a brief look at ways in that you can maximize the accuracy of your histogram in a few easy steps.
How to maximise your histogram
There are four primary things you need to understand and be careful with when maximising your histogram. I will touch on each one, and a simple Google search will bring up much more in depth explanations that I can give you.
The first thing you should do is choose a colour profile from your camera that is as flat and low contrast as possible. Stay away from Vivid and saturated colour profiles. The flatter the profile the better. This was the histogram isn’t confused by the bright colours when looking for highlighted areas.
The second thing you should do is avoid using any dynamic range enhancements such as the Dynamic Range or D-Lighting settings that can be found on most cameras. Again, this will force inaccurate measurements of the light as the camera exaggerates the light areas in your image.
Thirdly, and one that so many forget about is your white balance. Make sure that you use manual white balance as with auto white balance, your histogram can really be fooled when it reads a scene wrongly (which it can do a lot of the time in certain conditions).
Finally, your choice of AdobeRGB Vs sRGB will also have an effect on your histogram, as AdobeRGB had a larger colour gamut compared to sRGB, meaning there’ll be a discrepancy in you histogram once again.
Other things to consider
Of course, while these measures above will help get your histogram accurate, there’s still one more setting that will have an affect, and that is your ISO setting. But realistically you need this option more than the others mentioned, and in most cases you will be trying to keep the ISO setting as low as possible in your composition.
All of the above is relevant if you are shooting in raw. If you are a jpeg shooter, you may have to compromise the colour profile setting, or tweak your image later in post processing.
Every situation is different, and solely relying on your histogram is obviously a huge mistake. However, getting the histogram as accurate as possible is important. Be sensible, use your histogram, highlight warnings and any other tools you may have on your camera, Most importantly though is use you eyes!