Chances are, many of you have stopped to enjoy a sunset and taken a quick photo of your significant other to capture the moment. Chances also are that when you looked at the preview on your LCD (instant gratification!), you found that it was quite different than what you were actually seeing. Not in a bad way. In fact, some of those photos may have displayed even more vibrant colors and a nicely silhouetted subject. Not bad. Just different.

The reason for this is simply due to the nature of photography and exposure. New techniques and technologies, however, are blurring this discrepancy between our eyes and our images.

Exposures in photography are measured by “stops”. A one-stop change is simply doubling or halving one of the three elements of an exposure: shutter speed, aperture or ISO (”film speed”). Cameras are able to capture a tonal range of about 5 stops - from completely black to pure white. In contrast (no pun intended), our eyes can see the equivalent of about 13+ stops.

HDR imaging, or High Dynamic Range, refers to the creation images with a greater tonal range than is possible with regular exposures. This means vibrant colors in that sunset and details in your subject. It means images that can (though not always!) be a more accurate representation of what we see with our eyes. It also means the potential for images with so much detail and saturation that they take on a surreal look. The process of creating an HDR image usually involves bracketing a set of photos at different exposure values (or ’stops’) and basically merging them with Photoshop, Photomatix or other imaging software.

Below is an example of three photos - one “correct” exposure (according the camera meter) for the mid-tones, one for the highlights (sunset and clouds) and one exposing for the shadows (mainly the grass). An even more technical approach would be to take an exposure for each stop of contrast in the scene… 3, 5…. 9! The final (HDR) image is very similar what I saw at 7:25 am on September 2nd while enjoying the sunrise over Lawrence Lake in Outing, MN.

Click here to see a larger version of the final HDR image

Click here to see a larger version of the final HDR image

Another Example using a photo I took in the Boundary Waters, mid September. This was taken during the same photo shoot as ‘Sandbay Rocks’, featured in my Exposing 2007 post. I first created the HDR image and then converted it to a black and white photo - resulting in some very striking contrast.

Even a mediocre composition of Jon Stenseth’s dirty Audi S4 Avant demands attention when converted to an HDR image….

That’s one good-lookin cactus!

This entry was posted on Saturday, January 5th, 2008 at 1:25 am and is filed under General. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.