Rube Goldberg HDR

[Doug Nelson]

I've been reading a lot about HDR and tone mapping recently (two different topics, btw). My own experiments with bracketing failed due to my stubborn refusal to carry around a tripod. But I had an idea that I wondered: a) would it work, and b) has anyone already tried it?

Take 3 midrange non-SLR digicams (6MP each should be more than enough) and mount them together in such a way that they're all aligned facing the same direction. Some models are small enough that this wouldn't be nearly as cumbersome as it sounds. Set them all on manual exposure (unless someone can be clever enough to sync them up) and adjust one to +EV2 and one to -EV2. Then just figure a way to fire them all simultaneously and viola! You have 3 perfectly matched images to blend.

Crazy? Inspired? Already been done to death?

The guy that invented the panorama tripod head made a fortune, I'd bet there's some money here if someone could come up with a way to make a good bracket and sync system for this.

[Cameraken]

Hi Doug.

A similar idea has been used in the past for stereo photography

http://home.vicnet.net.au/~vic3d/pentax_rig.html


It would be easy to add a third camera.

Interesting idea.

Ken

[Ken Fournelle]

Would you not have parallax issues from camera to camera? Would the image from camera 1 be able to completely lined up with camera 3?

k

[JayBee]

Originally Posted by Doug Nelson

Then just figure a way to fire them all simultaneously and viola! You have 3 perfectly matched images to blend.

Nice idea but they would not be aligned. Parallax error I'm afraid. Even shift lenses suffer from slight parallax error if you are shifting the lens rather than the body.

Easiest way is to:

1) Use a TRIPOD!!!
2) Set your cam to autobracket three exposures or five or whatever it can do so you get exposures in the range -2 -1 0 +1 +2
3) Convert the RAWs to TIFF with NO CORRECTION (save for white balance etc)
4) Use your HDR program (or CS2)
5) Tone map

6) Voila!

JB

[palms1]

Maybe someone could answer me a question on this my little point and shoot has a facility to shoot 3 photo's one after the other ( called AEB ) at different exposure settings one would be automatic settings one overexposed and one under exposed would this be anything like whats required for hdr ?
Easy answer reqired not a camera geek

Palms

[Cameraken]

Hi Palms

Easy Answer - Yes

More
AEB stands for Automatic Exposure Bracketing (Usually average, over and under exposed)
Some cameras will let you choose the amount of over and under exposure.
These three images can be used by HDR software to extend the dynamic range.

Re Doug’s idea
There is now HDR software which accounts for camera movement between the shots so using three cameras should not be a problem. Or maybe Stereo HDR. Now that would be a first.

Another way to extend the dynamic range is to shoot with black and white film and use Red Blue and Green filters because black and white film has a higher dynamic range than colour film.


Ken.

[palms1]

Thank you Ken understood that
Palms

[Doug Nelson]

The problem with AEB is it never seems to have a wide enough range. Plus on digital cameras it can be several seconds between exposures, so tripod still needed.

As long as some care was given to mounting, I don't think parallax would be enough of a problem to worry about, at least it would be trivial compared to the scene or camera moving during multiple exposures.

pricegrabber.com has some excellent sub-$100 digital cameras, I'm almost tempted to try this. What's a good little digital camera with a USB port that would allow firing, exposure, etc., via the USB port? I'm thinking that would be the easiest way, then hack up some software that does all the heavy lifting.