Sunday, December 6, 2009

Fake HDR (High Dynamic Range)

Week 25

OK, I'm halfway through this exercise now with only 25 weeks more to go!

This week I'm (kind of) blogging about getting additional dynamic range out of a camera using HDR - High Dynamic Range - which are digital methods of combining one or more photographs with different exposures. Well, actually I cheated and only used one exposure but more about that later.

Why would you want to do HDR? The potential need arises when there are high contrast scenes with very bright areas as well as dark areas with important details. The human eye can handle this pretty well but a camera only has so much range. HDR manages the trick by taking exposures for dark, bright, and in-between areas as needed then blending them.

There is software, with Photomatrix being a popular one, that will do the work for you and allow easy adjustment. It can also be done in Photoshop although I've not had great luck there. There is an example here of a photograph I took in Australia and applied HDR to in Photoshop. It isn't that great, the area around the sun is burned out even with HDR. Like I said, I haven't had great luck with it. I've also done it manually where I superimposed two exposures and blocked out the over or underexposed portion with a mask.

Here are some other considerations for HDR:
  1. It isn't reproducing what the eye sees - it is squashing exposures into a narrower range

  2. It can give some wild colors and not look very realistic

  3. It doesn't work too well if things are moving between exposures

But it can give some really neat effects when not overdone, although it isn't for everyone. Another way to handle high range is with a graduated filter, at least with some scenes where the sky tends to overexposure.

I personaly like the look when blended back. In fact, it is possible to get something of the look without using HDR and that is what I did on this week's picture. Click on it to enlarge and see what is going on. There is a lot of detail under the bridge for example that wouldn't normally be there and the clouds reflected in the glass of the building really pop. I've left some of the wild color as well as gritty detail that can occur when you use this method.

The tool I am using is a Photoshop plug-in called Topaz Adjust 3. It gives a range of effects with this being one of the cooler one. After adjusting the photo for keystoning (it is wide angle) I cropped and then applied the Topaz Adjust 3 "Psychedelic" filter, dialed back the layer, gave it a vignette, and sharpened. That was all.... The original photograph without adjustment is here.

The camera is a Nikon D3 set at ISO-200 with an exposure time of 1/250 of a second and a Nikkor AFS 14-24mm 1:2.8G ED mounted wide at 14mm with an aperture of f/8.

Idea based on Extend Your Range, pages 32-35 in the book 50 Photo Projects by Lee Frost.

1 comment:

  1. I really like the sky reflected off the building! Good one, Dad.

    I went to a book signing this week for a blogger who is a food photographer (and she lives on a ranch, it's pretty cool). Anyway, a DSLR camera was the must-have accessory. So you're cutting edge yet again, since you haven't been seen without a DSLR in several years :-)

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