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HDR for panoramas

High Dynamic Range

What is it? A way to capture and represent scenes that contain extremely high contrast. We see high contrast scenes all the time but the brain has excellent compensation algorithm which has been under development for millions of years. Sunlit forests, interiors with windows, or division between night and day on the moon are all examples of high contrast scenes. When a beginner first photographs these types of scenes, they are often surprised that the film does not match what they saw.

How can you use HDR for panoramas? By shooting multiple exposures or using special equipment, you gather the raw materials for constructing a high dynamic range image.

To date, one way photographers deal with high contrast situations is by shooting two exposures at each click-stop and then stitching each bracketed set of images into panoramic images and melding the multiple stitched images together in Photoshop. You can also do the melding on individual images before stitching. Either way, that's extremely time-consuming, and you still end up with an 8 bit/color image.

The promise of HDR is in reducing the huge amount of time involved in post-production of high contrast scenes, and preserving a wide gamut of the dynamic range in the image file.

The following tools and tips help create or work with HDR images:

Aldo Hoeben wrote an article on "Adaptive Dynamic Range" panoramas

Reindeer Graphics' Optipix Photoshop plugin creates 16-bit HDR images from a series of 8 bit images

Eric Krause has a set of PS Actions (free), "Contrast Blend" & "Align Layers" to create HDR images

PhotoMatix, Windows (and OS X in beta) software to optimize the combining of two images shot with different exposures:
http://www.multimediaphoto.com/photomatix/ (Ted Chavalas posted a demo he did in PhotoMatrix at http://www.panoscan.com/PhotoMatrixPage/Photomatrix.html)

HDRshop, Windows software to combine three shots

For HDR image editing, there's an open source UNIX (& OSX) program, CinePaint (formerly Film GIMP): http://cinepaint.sourceforge.net/

Also check out the HDR image editing product Photogenics HDR: http://www.idruna.com/

Greg Downing's plugin for HDR:

Spheron A slit-scan panorama cameras for capturing high resolution cylindrical and spherical panoramas and supports capture of HDR (high dynamic range) images

The comparametric toolkit is a collection of programs for creating high dynamic range images

Greg Downing's webpage on Stitched HDR images documents his process

About OpenEXR, a 16 bit image format developed by IL&M

Unfortunately most stitching tools do not take advantage of 16 bit/color source images. As interest in HDR grows, and 1,2 or 3Ghz desktop PCs become commonplace, I expect the tools will make it easier.

© Copyright 2006 erik goetze.
Last update: 1/6/06; 2:41:54 PM.

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