Convert Raw Photos for HDR Photography
If you shoot in Raw, you don’t have to convert those photos to another format (TIFF or JPEG) before you generate the high dynamic range image. If you wish to, however, you can convert your Raw photos and save them in one of a few different formats.
With high dynamic range photography you can tailor your workflow to the amount of effort and picture quality that are important to you. You also don’t have to shoot Raw photos if you don’t want to or your camera can’t.
Different approaches yield different results, of course. Consider these issues when deciding whether to convert Raw photos:
Quality: In general, you achieve the best quality by shooting Raw photos and converting them to 16-bit TIFFs for use in HDR. Trailing this option is converting the Raw photos to 8-bit TIFFs, then using camera JPEGs, followed by using the unconverted Raw files themselves (the HDR software converts them automatically, leaving you no control).
Choose the quality you need and can afford, bearing in mind that different software choices can produce different results.
The figure illustrates two small sections of a tone mapped HDR image created from different source image types. The original five bracketed Raw photos are Nikon NEF files and have been processed through Nikon Capture NX 2 to create the 8- and 16-bit TIFFs. The JPEGs were generated in-camera. Photomatix Pro was used to generate the HDR and tone map the result.
JPEG — and sometimes Raw appearance — can be dramatically affected by the processing options you choose in the camera.
Comparing two areas reveals different effects of the format in use:
Clouds and sky: The TIFFs are relatively equal in quality, with details and textures well preserved. You can see the nuances of the cloud and sky in both TIFFs. The JPEG and Raw have lost detail and take on a color cast by comparison.
Words and sign: All four source image types show fairly good quality for this man-made object. The JPEG is surprisingly good although the colors are close to being oversaturated. Notice that the image generated from the Raw photos is the softest.
Workflow: If you’re shooting a tremendous number of photos for HDR, or perhaps you’re shooting a large number of photos in general and need to fit HDR into an existing workflow, using different processes for different images can be an issue.
For example, if you use Apple Aperture and that’s where you spend all your conversion and editing time, using something else can throw a wrench into things. Choose the workflow that makes you want to create HDR, not throw it out the window.
Cost: Cameras, gear, and most software cost money. If your supply of cash is limited, start where you can (the inexpensive and free stuff) and move up to more expensive options when you can. Don’t sweat it.
Single Raw exposures: The same principles apply to converting single Raw exposures.