Monday, January 19, 2009

HDR Photography

High contrast scenes present great challenges to photographers and cameras sensors (and film media). The meter in our digital camera can only meter what it sees which is the "average" tone in terms of light/tone and colors. Without a good understanding of exposure and a clever use of filters (ND filters specifically), the resulting image will often be over or underexposed and flat leaving the average photographer exasperated.

Aspiring photographers have all been teased by the vibrant imagery we see on Calendars and Photography Books, we yearn to be able to also create these beautiful images. That day has finally arrived (well, sort of) with the advent of HDR High Dynamic Range photography - the new kid on the block, the latest obcession if you will. A new genre in digital photography is indeed here. In simple terms, HDR technique combines tonal properties at each end of the spectrum to produce a very rich and vibrant imagery. For a start, one has to take three identical images of the same scene/object: one at the set exposure, one overexposed and one underexposed. The easiest way to accomplish this is to set the camera on AEB (Automatic Exposure Bracketing) so the camera would take three shots: one at 0 on your meter scale, and the second shot at -2.0 and the third at +2.0. Because you need the three images to be taken from the same spot, a sturdy tripod and a wireless remote are essential to reduce camera shake.

Once you have the three bracketed images, you will need the help of a HDR software to put that tonal details together seamlessly. One such software is Photomatix. A trial version can be downloaded here at Photomatix. There is a PC and Mac version. It is a standalone software but a plug in is available for Photoshop. The trial version does not expire so long as you can put up with the watermark across your finished image. The price for the license is $99 and in my opinion it is well worth the investment if you plan to do a lot of landscape and high contrast scenes. Good way to test the software and see the end result and decide if this is your kind of art.

My first go at HDR tone-mapping - Evening at a city park shrouded in thick fog, shot at ISO 400

The software is extremely easy to use and accepts RAW files from my Canon 10D. Just drag the three image files and if you select the default settings, the software will do the rest. I would have preferred to shoot at ISO 100 but the thick fog meant I had to keep my shutter open for over 20 sec which would be really pushing it. Nevertheless, I was happy with the result. HDR works best with bright imagery but that is not a hard and fast rule, it is always good to experiment and find your own style.

I found a collection of beautiful HDR images at 17 beautiful HDR images

Did a search on Amazon for books on HDR Photography and found a handful of books written about HDR photography. One with high marks is:

Complete Guide to High Dynamic Range Digital Photography
by Ferrell McCollough (Author)

"It’s the latest and hottest technique, made possible only through digital. High Dynamic Range photography is the process of taking several pictures of a scene at various exposures, then merging them into one file. So the entire photo can look crisp and detailed, from highlights to midtones to shadows—and photographers needn’t sacrifice any part of their image. And the best way to master this exciting technology is with this thorough, easy-to-follow, and visually spectacular guide. No other title does justice to these cutting-edge techniques, which actually take the viewer into worlds far beyond normal photography—sometimes even beyond normal human perception. Ferrell McCollough, a widely respected photographer, pushes the boundaries and inspires others to pursue their artistic vision, too. The amazing results simply can’t be achieved any other way."

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