Sunday, September 23, 2012

High Dynamic Range Processing

I've mentioned High Dynamic Range (HDR) processing a few times and now have created a label to help organize posts that deal with the technique. What I haven't shown yet is the finished product with the separate images used to create the final image.

On my walk this morning, I spied a nice reflected water image with a sun about an hour old. I knew I'd have some good material for HDR processing.

To create an HDR image you start with three or more images bracketing normal and two stops under and over exposed. I always use three because that's how many shots my cameras will automatically bracket. The software then combines the exposures to create a combined image. There are many different ways to process the image to get different looks. Generally, a more natural feel is preferable for landscape images.

It's important to use a tripod so that the three images line up without blurring or ghosting. Today, however, I managed to lean the camera on a bridge railing with acceptable results.

First, I'll show the three base images from which the HDR image was created. All these shots were made with a Canon EOS 5D Mark II with EF 17-40 f/4L USM lens at 26mm. The scene, of course, is the abandoned Cluett, Peabody and Company textile mill on Peebles Island.

Normal - f/8, 1/125 sec., ISO 100

Underexposed - f/8, 1/500 sec., ISO 100

Overexposed - f/8, 1/30 sec., ISO 100
As you can see by the shutter speeds, there are two stops of difference between each of the three images.

I have several different software options for HDR processing. I used two different methods and preferred the result from Photomatix Essentials. Here is the result of the three images above, together with a landscape orientation of the same scene.





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