Highlight Warning System

Take a look at this image and notice the loss of detail in the highlights, no tonal quality in the rest of the image and no detail on the tree. Even as a silhouette scene, the image's highlights are completely blown out and the sunset looks distorted. How could this have been prevented or corrected at the time of capture? This could have been a different image if the Highlight Warning System had been used.

In the first place what is a Highlight Warning System (HWS)? That is exactly what we are going to discuss in today's blog. Before digital cameras one had to mentally understand what will happen to our images each time we change the exposure settings for the lighting environment we are working in. The Highlight Warning System is a powerful feature on our new digital cameras which indicate the area of an image where exposure is beyond the capability of the camera. In this image it would have shown blinking lights in the white area surrounded by the orange sky, indicating the highlights are over-exposed or "blown out". On your digital camera you will have to go to your menu and make your monitor preview active with the HWS turned on. When this feature is activated you will visually be able to see where you have overexposed your image.

Digital images have exposure limitations just like conventional film and when you go beyond the latitude range of your camera or film, you will literally have no pixel data and unfortunately an irreparable image. You can lighten up the dark parts of an image, but you can't do anything with blown out highlights.

If you want to use a split grad neutral density filter, it’s an easy fix using your camera's monitor with HWS active. If your first image indicates you have blown out highlights, attach a split grad neutral density filter across the highlight problem area, and take another image. If you have no blown out highlights on your second image, then you have a perfect exposure.

An alternative way to make a correction for our blown out highlights, is to dial in exposure compensation to properly expose for the highlights. If after making the correction, you have no blown out highlights, then you have a correct exposure preserving all of your pixels. This may result in too dark of an image and lack of detail in the shadows. especially if you are out just before sunrise or after sunset, when low lighting conditions exist. If so, we could use the HDR method in Photoshop discussed on a previous blog to obtain a full tonal image, preserving all the highlight detail as well as in the shadows, by merging multiple images, or you could try a combination of both the split grad filter and exposure compensation to properly expose both highlights and shadows.

The HWS is a wonderful way to learn light and exposure as well as get high quality images every time you go out to capture the perfect scene at the perfect tyme.