19 June 2008


The green bog

Burns bog field trip - 25I accompanied my older daughter's school field trip to Burns Bog in Delta, south of Vancouver, today. We had fun, and managed to avoid any heavy rain.

I also took the chance to create some more high dynamic range (HDR) photos. That involves taking three or more pictures at different exposures, and then combining them in software using a technique called tone mapping.

You can see what that does below.

On the left you can see my camera's calculated single optimum exposure, the "best pick" the camera would normally make. Nothing wrong with it. But on the right is the HDR version I created, combining the left-side exposure with two others, one brighter and one darker:

Burns bog field trip - 29 Burns Bog Log HDR FInal

The extra vividness of colour I chose to put into the tone-mapped HDR is obvious, but if you examine the large version, you can also see a lot more detail in the shadows and highlights of the image. That's the high dynamic range we're talking about—in a normal photo, some of the shadows might be totally black, while some of the highlights might be blown out to total white.

Tone-mapped HDR photos involve a lot more decision making than traditional pictures, because depending on how you manipulate the image, its appearance can vary widely, from slightly enhanced (the way filters and darkroom work used to punch up film images) to strangely surreal (more like cross-processed, solarized, or otherwise highly altered film images).

So far I've been photographing nothing but plants in HDR for some reason, but I will play with the technique some more and post additional pictures to my Flickr HDR set.

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Very nice! My husband has been playing around with it but I just don't have the brain power to make HDR happen. I feel lucky when I get ten good shots out of 50.