Monday, March 15, 2010

High Dynamic Range

So, this is a little different than the normal stuff I write about, but I still consider it part of alternative photographic processes, even though it’s something you do in post-processing.  High Dynamic Range, or HDR, describes merging photos using Photoshop or a similar program to achieve photos with a higher range of luminance.

In standard photos, you can usually expose to highlights or shadows or midtones, but our eyes have the ability to see all those ranges is a more dynamic way than our camera can capture.

This is a really great thing to do for all those pictures of white Mt. Shasta and it’s dark tree line.  If you want to give it a try, the first thing is to look into your camera’s settings and figure out how to take multiple exposures (2 or 3) at different exposures using the same aperture.  For my Canon 50D, I set the mode to Aperture priority and go into the exposure settings in the menu and tell it to bracket to 1 stop above and below, so the camera will take a series of 3 photos.

Example of photos:

Standard exposure – this is a decent photo of the mountain and fairly typical for what is seen, but the mountain is actually blown out a little because of the difference in tones.


Over exposed by 1 stop


Under exposed 1 stop


Then, these are merged using different programs.  In Photoshop, you use the File>Animate>Merge to HDR function (Google for more comprehensive tutorials).

The result:


You can see how the trees are properly exposed and the mountain is a rich white with dynamic shadows and dark ridges.

Anyway, sometime to play with if you feel like it.  In the meantime, I’m working on a couple different film processes and use of different cameras, but film takes time to process and the COS darkroom is closed this week, so I promise an update soon-ish…

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