HDR

Last year, I mentioned High Dynamic Range (HDR) photography, where you combine multiple pictures taken at different exposures to create a single picture where all of image is properly exposed. I didn’t do much with it at the time because, a) it’s not really possible when you shoot slide film, and b) there didn’t seem to be a good hdr program for linux.

a) was resolved when I went digital in November

as to b), I just wasn’t paying attention. I was looking for something in the Gimp or a Gimp plugin. I should have looked for PFSTools, PFSTmo and Qtpfsgui. PFSTools is a command line tool for creating and manipulating HDR images in their high bit count format. PFSTmo is a package of command line tone-mapping algorithms that will take the HDR images and map them back to 8 bit per channel images. Finally, Qtpfsgui is a GUI front end for all of this.

I’ve only just started playing with the tools, but take a look at the following 3 images, each with a different exposure (exposure compensation of -2, 0 and 2 EV):

orig-1.jpg orig-2.jpg orig-3.jpg

From these images, I created an HDR image which was then tonemapped using different algorithms to produce the following images (going from most to least realistic):

house-hdr2.jpg house-hdr3.jpg house-hdr1.jpg

Personally, I like the middle one, although I do wonder why the trees directly behind the house look odd in all of the images. <shrug>  I’ll keep playing around and see I can get a better sense of the options.

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