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03/29/2003 03:22:28 PM · #1 |
I came across this technique a while back. There have been many studies concerning it, but not before now has there been a plugin that can do it for you. First things first, lets look at some results:
//www.cs.huji.ac.il/%7Edanix/hdr/results.html
Here we see the process applied to a few images (clicking on them, and you can see the results of different techniques, as well as the sources images). The actual effect of this process is very apparent in the Belgium House example, clicking it will reveal the sources images in the lower part of the page, you can see that none of the exposures were very nice, but combining them with this process created a very nice result, combining indoor light and outdoor light. The process is a bit like this:
You take multiple exposures of your picture (as little as 2, as many as 10..15.. ). This can either be done with exposure compensation, or by locking the aperture, and taking photos at varying exposure times. These photos are then "combined" in a program like HDRShop, to create what it called a "High Dynamic Range Image" or HDRI for short. This is a format that stores color values in 32 bits, allowing a very high range of values. Having explained the long process, RAW type files can be similar to this if the camera saves the raw format as a wide exposure range, and can directly be loaded in HDRShop and will be interpreseted the same way as a HDRI. TIF can also hold this type of information, but both the RAW and TIF formats will only hold this information if the camera actually saved it. A bit of experimentation would be needed to find out if the raw/tif formats of your camera actually store more information than your typical JPG (other than the fact that it doesn't compress).
When you have your HDR image ready, you get the tonemapping plugin for HDRShop and can get to work. the plugin is available here:
//www.gregdowning.com/HDRI/tonemap/Reinhard/
and the process for stitching together many exposures is explained here:
//www.gregdowning.com/HDRI/stitched/
now, i haven't been able to test this myself much, as i dont have my camera (out for repairs), and the parameters in the plugin aren't very user friendly, but i'm sure someone here could use the process and play around with it if they have time. I plan on trying this out for sure when i get my camera.
Have fun :)
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03/29/2003 04:57:19 PM · #2 |
Oh, this is so cool! Too bad it is not DPC legal. The parameters for the plugin are certainly foriegn, however for those undaunted by math, this:
//www.cs.ucf.edu/~reinhard/cdrom/tonemap.pdf
explains things quite nicely. WARNING! This file may be lethal to anyone with allergies to mathematics! |
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03/29/2003 06:14:40 PM · #3 |
thanks for that link, i hadn't seen that. I've started playing with some *.hdr images i could find on the net ( //www.debevec.org has a few ) and it's working great.. cant wait to try this with my own photos..
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03/29/2003 07:34:10 PM · #4 |
| Math? I'm allergic to the post that is supposed to even explain what the heck this is ;P What exactly is the point? Are you trying to have the whole picture exposed properly or something? |
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03/29/2003 07:51:46 PM · #5 |
basically, yeah.. if you look at the Belgium house example from my first post ( //www.cs.huji.ac.il/%7Edanix/hdr/pages/belgium.html ), it's a photo taken inside, which shows some indoor parts, but also is open to the outside. At the bottom of the page, you see a series of 9 different exposures.. and none of them are really that good.. But when using tone-mapping, combining different exposures (automatically) for different parts of the image, the result (the top image) is pretty amazing.
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03/29/2003 08:41:32 PM · #6 |
This is also something that Fuji's 4th generation super-CCD is purporting to address - basically, with a second layer of light-intensity sensing sensors. If it works, the rumoured 701 will be able to do that as 1 shot - then we'll all be able to take that car-park shot.
My problem with it, though, is that it looks like a manilupated image, rather than a photograph. Perhaps that's just familiarity with present photographic technology, and no doubt there were gripes about the first colour photos.
Anyway, I LIKE high dynamic range photos: light is information, and too much light is too much information.
Ed
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03/30/2003 12:02:23 AM · #7 |
I take it this is only Windows (looks it). But, there is a plugin for photoshop called Ozone that seems to do this also, but with a single image. Not sure if it is DPC legal either, because (with the one I have played with-but only get to see a small image with demo), it works on the different colors or luminances within the picture and lets you adjust them.
It is called the "Digital Zone System." Looks great, but I don't have the $75 for it yet.
//digitalfilmtools.com/html/ozone.html
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