Friday, May 13, 2011

How to Create an HDR Photo from a Single RAW or NEF File

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Making an HDR photo from a single NEF file is useful when the scene you're shooting has stuff moving around in it. Basic requirements: To make an HDR photo from a single RAW or NEF file, you need the following: (1) A camera that shoots in either RAW or NEF, (2) photo editing software that works with these file formats, and (3) a software program that allows you to create HDR photos, such as Photomatix or Photoshop.

A while back, I went through an "HDR photography" phase. Probably most people do this when first introduced to the technology because you can get some very cool effects with it. In case you're unfamiliar, HDR stands for High Dynamic Range. It addresses the problem that normal photos only display a slice of the total range of light available in a scene -- a much smaller range than the human eye can see -- which results in lost details in shadows or "blown out" lights. For a bit more background and a couple of examples of this, see Painting from Photos. To increase the range of light in a photo, HDR photography combines the information from two or more photos of the same scene, taken at different exposure settings, say -1, 0 and +1 EV for example.

Because they're made from a sandwich of two or more exposures, HDR photos can come out blurry when your subject or part of the scene in the photo is moving. This is also an issue if you're trying to take multiple exposures with a hand-held camera because your hands can't hold the camera absolutely steady. Even on a tripod, the camera can be shaken by a passing breeze. In addition, the camera can shake itself slightly just with the movement of the shutter.

One way to get around this problem is to shoot a single photo in either RAW or NEF format and then make the different exposures needed for your HDR photo from this file. In case you're not familiar with them, NEF is a format used by Nikon, and RAW is used by most everyone else. Most SLR cameras have the ability to shoot in one of these two formats. RAW and NEF files store a great deal more information from the scene than do JPG files. As a result, these files are very large. Mine generally run from 12 to 20 MB.

After taking your photo in RAW or NEF format, you need to upload it into your photo editing software, which probably came with your camera. I use Capture NX 2.0 to work with my NEF files. You can also use a third-party program such as Photoshop. Make any edits that you want to the photo, and then save two or more versions of it at different exposure settings, for example -1, 0, and +1 EV; or -2, 0, and +2 EV. Then save the resulting files in JPG format. Finally, create your HDR file from these JPGs by using a specialized program such as Photomatix or the photo combining features of Photoshop.

Here are some examples of HDR photos I made in this manner from shots I took one day when we went sailing with our friend, Michael.

Everything looks ship-shape, Cap'n.
Off we go! Isn't that Seattle over there?
Michael's sight-seeing. Hey, who's at the helm, anyway?
No worries. Bill's got the tiller.
Wow, look at that big boat over there!

Ah, Bill, I think we've had a close enough look.
Who knew playing chicken with a container ship could be so exhilarating!
Time to head back.

Ride's over Bill! Bill! BILL!
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Make HDR photos even when parts of the scene are moving.

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