Tag Archives: HDR

HDR with an IR Converted D200

When I had my D200 converted to (deep) IR I nearly immediately noticed that the tonal range was significantly less than usual.  I was shooting RAW to make sure I captured all the data, but when I got it back to the computer it was totally unnecessary since the histogram showed the image was neither stressing the top nor the bottom of the possible 8-bit range, much less the 12 bits or so that the D200 could normally capture.

That didn’t make me real happy, but when I tried to tone map a single image in Photomatix, the limited data really became evident:

Single image tonemapped

Single image tonemapped

D200(IR), RAW, ISO 100, F8, 1/40

The banding in the clouds at the top is the proof of the narrow tonal range.  The range of IR is there, but just not captured in a single narrow tonal range image, as is evident when multiple bracketed images are used with similar tone mapping settings on an true HDR image:

Three stop bracket tonemapped

Three stop bracket tonemapped

D200(IR), ISO 100, F8, 1/40±1 stop, 3 frame HDR

No banding or any evidence of too narrow tonal range.

So, I’ve learned that with the D200(IR) I need to bracket at least three exposures to get an adequate tonal range for tone mapping.  Not sure why one exposure won’t capture a full range of data…

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Notes on Shooting HDR

2008-07-29-18-16-52

(This post is actually forum conversation with a coworker. I thought the content might be useful for others.)

A few notes I’ve learned as I’ve tried to figure HDR out. I’ve started turning EVERYTHING on manual:  focus, white balance, and exposure. I used to stay in my usual aperture-priority mode, but noticed on my D200 that when I do auto-bracketing, it seems to do a new exposure reading between each exposure and I could get shots that were not really -2, -1, 0, +1, +2, but maybe -2, -2/3, 0, +1 1/3, +2. Photomatix seems to take it in stride, but it still bugs me so I fix it by setting the exposure to manual and then doing the autobracket.

And yes, I agree that having plus and minus two stops usually works out best. I would like to have a two-stop increment option on the autobracketing so I could just do a -2, 0, +2. I’ve seen a comparison between images using those three images and the same HDR tonemap that includes the -1 and +1 and there’s very little difference.

Something else I’ve found is that I need a camera with a faster frame rate. Like in the shot above.

It was hand-held, which I don’t like to do, but not only was there camera movement between shots that Photomatix handled fairly well, but there was also movement in the river and boat, which is really bothersome. I guess I could take the tonemapped shot into Photoshop with one or two of the individual shots and mask in those areas like some of the best HDR shooters do, but wow, what a pain! I think the best solution would just be to buy a D3 and crank the shots in twice as fast.

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