One of the best features on a Digital SLR camera is the highlight over-exposure warning. TURN IT ON!
There is NO feature on my digital camera that I use to get the ideal exposure in my digital photography more than the Highlight Over-Exposure Warning, especially when dealing with difficult exposure situations. I use it more than I use the lightmeter.
With any digital camera, the worst thing you can do is over-expose your subject. Pure white in any digital photo is a lack of information… whereas under-exposure is a lot of information. So we want to be most careful with the highlights (right side of the histogram)… and make sure there’s not too many or that they don’t occur in important areas of our photographs.
It’s very difficult, if not impossible, to add detail that isn’t there and keep your photo looking natural.
So if your camera has this feature… turn it on! it takes a little bit of getting used to. It has even has been described as “annoying” by people. But annoying is what you want, I like having that annoying reminder blinking in my face to remind me to watch my highlight exposure.
Here is a simulation of what it would look like in camera… Red areas in the picture shows that certain areas are PURE WHITE and have absolutely no detail there. (Of course, your camera will display image in color)
Example of what your Highlight Over-Exposure Warning might look like on your screen (I chose a B&W image with red warning so it would stand out better) Any detail that is over-exposed will show up in your review photo on your camera’s LCD as a blinking contrasty color. My Canon cameras blink black in any areas that are going to be rendered as detail-less white in my images.
When the blinking area is too big and / or covers very important areas of the photograph, simply change your exposure to give less light until the blinking goes away (stop down, choose a faster shutter speed, reduce your ISO or use the Exposure Compensation control)
This is one of the easiest things about digital photography and using manual exposure (or even exposure compensation using automatic modes).
To me it’s simple… set the exposure to where I think it should be based on my light-meter or even by intuition. Then adjust your exposure with shutter speed / aperture / or ISO until the white high-light areas of your photo just start to blink… then I go 1/3 stop less exposure than that to guarantee I will have some detail in there.
Of course not all pictures are the same, and you do have to learn to read your scene and figure out what areas you want to be near pure white. Of course some photos I am more than happy to let the pure whites blow out.
Here’s a photo where I didn’t have any choice but to let some of the highlights blow out… if I would have tried to keep the white uniform from over-exposing, his face would have been too dark, so I gave enough exposure to make sure the face was exposed properly and let the highlights fall where they may.
It’s the exact opposite thing for those of us who shoot Black & White Negative Film, where our goal is to make sure we give our film enough exposure to get detail in the shadows, then fix the highlights in processing and in the darkroom. With negative the rule is “Expose for the shadows… develop for the highlights”
Of course… you should always learn multiple ways to calculate exposure, especially since this method would be VERY difficult in the unfortunate even you break your LCD screen or you get transported back into time and HAVE to use film cameras!