Proper Exposure With a Digital Camera
For many years, photographers shooting transparency (slide) film were taught to “always expose for bright, detailed highlights.” This rule is even more important for images created using a digital camera. With digital cameras, the best exposure is always the one that records the brightest possible highlights with meaningful detail. Underexposed digital images exhibit far more camera noise and have far less tonal variation than images that are properly exposed.
The digital camera’s sensor does not see the world the way our eyes do. With our eyes, brightness and tonal variation are linear, but for the camera this scale is logarithmic. Basically, this means that the camera can record lots of tonal variation at the brightest end of the spectrum but it captures very little tonal variation at the darker end.
Now you have to be careful here because the line between empty, blown-out highlights and bright, detailed highlights is a very fine one. For maximum image quality you must expose so that your highlights are as bright as possible.
Image enhancement programs, like Adobe Photoshop Lightroom and Adobe Photoshop CS4, can do amazing things to polish up your images, but the old rule of “garbage in, garbage out” still applies.
Making tones darker with sophisticated image enhancement software is no problem, but brightening up an image will always make it appear to have more noise. There is simply no substitute for nailing the exposure while you are out in the field shooting.
2 Stops Underexposed
One Stop Underexposed
Perfect Exposure
One Stop Overexposed
I suggest reading Real World Camera Raw with Adobe Photoshop CS4
You can also find more information on the need for proper exposure with a digital camera in this online article:
Expose (to the) Right by Michael Reichmann
Filed Under: FAQ • Getting Started • Tutorials
About the Author: David’s sports and landscape images are often used on the web and in outdoor sports publications. He has an extensive knowledge of digital photography and is an Adobe Certified Expert in Photoshop and Adobe Photoshop Lightroom. David is a talented instructor and his entertaining teaching style works for students of all skill levels.
In 2009, David Marx led digital photography programs for the 
This article is very interesting to me because I heard the opposite before. So far I thought that slightly underexposing your picture has two advantages:
First, in dark conditions the critical exposure time can be decreased and secondly the current CMOS chips of digital cameras capture more detail in the darker end than on the bright side so that it might be easier to get overall detail when handling an underexposed picture.
Nice setting I found by a quick web search: http://www.petapixel.com/2009/06/09/underexposing-vs-overexposing/
Obn,
I was told this for a long time, too. However, it ends up that the facts are quite a bit different. Today’s chips capture far more data on the highlight end than on the shadow end.
The article you referenced is untrue, unfortunately. Recovering data from the shadows results in very poor-quality pixels; those filled with noise and digital artifact.
This is particularly true when shooting Raw images. If one is shooting in JPEG, the tone curve applied to the image as it is processed in the camera can clip highlights and shadows from an image that would have been perfectly usable as a raw file. That’s one of the reasons it’s so difficult to determine from the preview on the back of the camera. Even if you are shooting in raw, you are looking at a JPEG preview on that little screen showing a JPEG image’s contrast.
-Scott
Hi Scott, thanks for the clarification. The only benefit of underexposure is having a faster exposure. I’m shooting RAW only and will have in mind the facts presented here from now on
Kind regards, Oliver
Scott,
While it’s true that todays sensors capture far more detail in highlights than in shadows, this has nothing to do with blown out areas of a photograph, where detail is completely lost. It’s far easier to blow out a photograph and lose a lot of highlight detail than it is to drastically underexpose and lose as much shadow detail.
For example, when taking group portraits outdoors, it’s better to leave with an underexposed photograph with some clipped shadows than it is to have the faces blown out.
If you capture all the highlights WITHOUT clipping them, then yes… you’ll have more detail and “higher quality pixels”. I think the point of the article was that, if you have to swing too much one way or the other, it’s safer to underexpose.
You’re absolutely correct. When it’s gone, it’s gone. If you lose detail in all three color channels in a photo, then there is nothing to recover (either on the high end or the low end).
For a long time, however, I was worried about “blinkies” (blown out areas on the LCD on the back of my camera) that I would see. Over time, I learned exactly how far I could push things without actually losing detail in those areas. Even on photos with highlight-warnings, I was able to view full detail in those areas (when shooting in raw).
I encourage everyone to experiment on some non-vital images.
-Scott