Re: Photomatix and white balance


If you work from RAW images, you can choose a white balance to apply to all of the shots in a series. If you want to tweak the WB for each shot, do it in Digital Photo Professional, Lightbridge, etc., and convert to some format that Photomatix can accept.


Of course, it's very possible that the original photo of the Eiffel Tower showed just what you see--the light may have been different in different parts of the scene. See my images of the barn as an example. Those both came from the SAME series of three shots. The difference was in the WB I chose. Part of the scene (the barn) is in shade and part (the background and foreground) is in daylight. Which is better? Using "Shade" makes the barn grey but turns the background and foreground yellowish, as one would expect--"Shade" has an overall "warming" effect. Using "Daylight" does the opposite: the barn becomes bluish, while the background and foreground are more realistic. (It was nearing sunset--note the long shadows--so the "daylight" portions of the foreground and background will look yellowish even with "Daylight" white balance.) See my shot of the island in daylight for an example where the white balance is pretty uniform across the image. (That was done from JPEGs, I think.)


Here are some examples where the scene has huge dynamic range. The sequence was taken just before 9 AM PST on Dec 19, nearly the shortest day of the year, in Eugene, OR, at latitude 44 deg, more or less, so the light is slanting. Plus, some of the image is in shade, while other parts have bright very early morning light. (I took these because this much snow is very unusual here, despite the latitude.) I didn't take the shots to be "pretty" or even particularly "good," just to get a series that I could experiment with of a scene with an inherently wide dynamic range. (I took several series with different exposures, as well.) They were taken from my front porch, which was convenient, as I could set up the tripod under cover on a hard surface and not have to trek through the snow. I could also retreat into my house to keep my hands warm. There's only so much I'll sacrifice for "art's sake."


This shot is the original, using auto white balance.


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Now, here are several HDR renditions, using different modes in Photomatix, using the "as shot" white balance. There's no real need to go into details about the settings, in part because I don't have them, other than the broad description. The first uses Photomatix's "tone compression" mode, which is supposed to give more "film-like" or "photo-like" images. (Photomatix also has an "exposure blending" mode, which is much the way that Photoshop does it. That does not generate an HDR image...see below.)


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The next uses Photomatix's "details enhancer," which uses microcontrast to, you guessed it, "enhance details" in both shadow and highlight areas. This is obviously more dramatic.


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Now, here's the same methods but setting the white balance to "shade" in Photomatix. First, tone compression:


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Now, details enhancer:


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Now, here's the original after processing in Digital Photo Professional with "click white balance" plus an exposure adjustment to make the scene look more like snow. I tried clicking the white balance eyedropper on various bits of snow to see what I'd get and chose one that I liked. (FWIW, I like using the WhiBal card, but that would have been no better here because the light varies so much across the image.)


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Now, the Photomatix output with tone compression:





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Finally, with details enhancer. This is, perhaps, the best image, though the other two "details enhancer" images are also interesting. The "tone compression" images do look more like "normal" images.





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Note the rather dramatic differences among these images, even though they were ALL done from the SAME sequence of three shots (except for the "original" shot) using auto exposure bracketing at 0, -2 and +2 stops. To make matters worse (or better--depends upon one's POV), Photomatix has lots of adjustments that can make a big difference. I can't describe the differences--you should get the trial copy and experiment with it, yourself. I've used it on landscapes as you've seen here, flowers, garden plots with deep shadows and bright highlights, etc. The two main caveats in taking the photos are 1) to use AV mode to keep the DOF consistent (you may need to choose the ISO in order to get three usable shutter speeds) and 2) that NOTHING should move, if possible. That means locking the camera down tight, using a remote release or the self-timer (it will automatically take the three shots with one shutter release push), and picking subjects where nothing is moving very much. If something moves, it can create ghosts.


Oh, I need to also mention the way that Photomatix works. (Not HOW it works--that's far beyond me.) Once you have your sequence of images, you use Photomatix to generate an HDR "image." You should save that as a file (extension is .hdr), as it can take a while to create, especially from RAW files. Once you have the .hdr file, you can start from there at any time. You CANNOT "display" that image as-is because it more bits per pixel than your display and OS can handle. Then, choose "tone mapping" and Photomatix will create a preview. Choose either "Details" or "Tone Compression" in the tabs and the preview will adjust to that mode. Then, you can use the preview to choose options and adjust the 18,437 parameters (well, not really
that many, but it can seem like it--it's as bad or worse than adjusting curves in Photoshop or Photoshop Elements), etc. (I always start with
"Default" settings, which the folks at Photomatix have set up for
general-purpose uses.) If you're smart (I wasn't), you'll write down the settings you use for each rendition. (A good way to keep these might be in a text file that you keep in the same folder as the images. You could devise a template with a spreadsheet or table to make it easier.)