Hdr

As I already said:

The only way I can think of is a camera with 3 CMOS Bayern pattern chips behind a prisma.
Would be "easy" to made. Take a 3 chip camera and replace the CCDs with CMOS Bayern chips.
Than you need a circuit that let you control different exposure for each chip and the way they blend together - et voila - there you have it.

More sophisticated cameras may record 3 raw streams and you do the blending in post.

I think most chip and camera companys already working on HDR (like Panavision).
I predict HDR in consumer cameras in about 5 years.

That will be the next big hype, not 3D.

...well maybe 3D HDR .

Frank
 
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Here's a short video I did, mostly to prove to myself that the workflow was possible:
http://www.youtube.com/watch?v=zyBY01ZBo10
http://vimeo.com/4480709

basically I just setup a tripod shot, and filmed a few times at different exposures. I outputted a Tiff sequence from Premiere and trimmed everything down to exactly the number of frames I wanted, used Photomatix to make a OpenEXR HDR sequence and to align any images that went funky. Then in After Effects I motion controlled the final frames for further alignment and adjusted the levels for viewing of all the 32bit data and outputted a lossless AVI. Then in Premiere I did basic editing, addition of titles, etc....I also laid over some music from Sony Cinescore.

I was thinking of five streams/cameras at first, but then I realized that four cameras using beam splitters and a 4 way video combiner(used in security setups) could make for a pretty good setup where you could quickly see what areas were over/under/well exposed. There's a ton of post work to be done in such a setup, but it seems it's definitely possible.

The biggest problem I could see is getting the images on each camera to be framed exactly the same.....one university research team in my area used B&W sensors and a retroreflector to aid in alignment
 
monday1313 said:
nice work, what time of day was that shot at?
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Thanks, I believe I filmed around 11am-1pm in the St. Louis area. I'm actually quite sure if I would have waited for the right moment and perhaps picked a better subject the results would be much more evident....something with alot more shaded areas, alot of cumulus clouds, perhaps some lights here and there.

I'm really hoping someone with either access to a few cameras, or the cash to buy them will pick up the idea and expand on it so that motion can be introduced. The beam splitter mirrors are relatively inexpensive on ebay, and a rig could be built from wood or any material laying around.

I also believe that the further away a subject is, like say just moving clouds, the easier it could be to just forgo the building of a rig, and one could just line up the cameras close together(like say four cameras in a square pattern), and depend on Photomatix's ability to align the images, and then After Effects motion tracking for further correction....it might even be possible to do this by going full zoom and backing way up to record a more full scene....the big thing to remember though is that you always need a reference point for After Effects to base it's motion tracking on.
 
I posted results of my tests from 2005 somewhere here (can't find it now).

Basically, the shots have to be perfectly aligned or there's major problems with solarization. If it's off even by one pixel you'll notice.

You can get away with it with still photos, but it really shows up when there's out of phase movement.
 
It sounds as if you weren't doing HDR exactly, but just trying to combine a couple images to make one big well exposed one. While this is generally what we're shooting for in HDR, it doesn't exactly hit the nail on the head. One of the reasons HDR imaging programs can work well is the use of special algorithms, image alignment, and such things. I even go the extra step of saying that the images must not only be aligned, but the use of motion tracking must be used in After Effects to offset some jiggle in the frame caused by the HDR imaging softwares image alignment....as you see my results aren't perfect in my video,. but 2 seconds of solid video(48 frames)...seems to prove, atleast to me, that further testing could be done with possibly good results.


pmark23 said:
While procrastinating, I did a little though experiment, then backed it up with a real experiment.

The idea came to me while doing some HDRI (High Dynamic Range Image) work in Maya. You can read a bit about HDRI here.

It would be really cool if someone else tried this as well, particularly those of you with two DVXs, a beamsplitter, a 35mm lens adapter, and a bit of old-fashioned gumption (a machine-shop would help too).

I put the DVX in my backyard, and shot a minute of video while slowly opening then closing the iris. The camera was locked down, and nothing was moving in the background. The scene was a combination of dark shade, and bright sunshine -- a typical nightmare scenario for video.

Then I captured two stills into Vegas, one underexposed, and one overexposed. They were one on top of the other. Then I created a mask (automatically, using "Secondary CC" luminance mask) to "punch a hole" in the overexposed areas, so that the under-exposed "bright sunshine" parts showed through.

The result is that the dark bits were perfectly exposed (from the over-exposed shot), and the bright highlights were perfectly exposed (from the under-exposed shot).

There were problems with solarization on the overlapping areas (but I already knew this would happen from the "thought experiment" stage), and it took a bit of fiddling to get a good (but not perfect) match. A bit more experimentation and I think we would be able to get a perfect image.

I propose that a rig be made consisting of two DVXs focusing on a beamsplitter (prism), with a single 35mm lens at the front-end. One DVX would be configured to overexpose, and the other to underexpose. This way you capture as extreme a latitude as possible, and can "set" or "fix" the exposure in the NLE while editing. This will add another step during post-production, and ideally a plugin or separate software will need to be written to automate this.

Seeing that there are quite a few of you who are into making "35mm adapters", there's not a big leap into making a "HDRI/V" (as snappy a name as I could come up with) adapter. Unfortunately I don't have the resources.

One potential problem is syncing the camera's, but we'll only know if this is a problem when a complete rig is made. I think that natural motion-blur may make this a non-issue.

If this does work, when the HDX comes out this rig will CRUSH film. Do you hear me, film? We're coming to get you. Your days are numbered! :laugh:
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I feel like I'm not seeing anything in your examples that doesn't just look like normally exposed photography. Especially in the second one.
 
dougspice said:
I feel like I'm not seeing anything in your examples that doesn't just look like normally exposed photography. Especially in the second one.
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They are only proof of concept videos really, and the second is definitely not HDR....it only uses the workflow to display the fact that a little bit of mis-matching in the frames during the HDR image creation doesn't have a huge negative effect on the end result.

I do have to disagree about the first video though, as I would never have been able to expose the shot that well without lights and bounce boards....perhaps the next one I do, I'll do a side by side video...one showin a just generally well exposed shot, and the other side showing the shot done with HDR.

No matter what though I won't be able to fully display the HDR capability until I can film a scene simultaneously with multiple camera's, instead of fudging it through multiple takes.
 
I also wanted to point out that the first video is done without a polarizer....this is all straight through the lens.

I have some free time today, so I'll try to find a nice location that can really bring out the contrast and color in HDR.

I'll film the scene a total of five times...four at four different exposure levels, and a fifth that is just well exposed, and I'll display them side by side.
 
Here's a link to a video I did comparing regular video, color corrected/enhanced regular video, Plain HDR video, and tone mapped HDR video.

I would suggest watching the HD version in full screen, and perhaps pausing to inspect the differences, as the actual core video is only 20 seconds long.....as I knew the post process would be quite long, so I tried to keep it short. Sometime in the near future I'll be trying to do a 1-2 minute long HDR video incorporating more motion.

Here's the link:
http://www.youtube.com/watch?v=4sIEFDuuaSg
 
Sigh, if only we have a camera actually capable of capturing that dynamic range. The HDR with tone mapping looks very nice. The reference adjusted is actually pretty good; you got back quite a bit of details without losing too much overall contrast. I would suggest showing the videos one after the other instead of squeezing them all on the same screen, it would be nice to see high res examples.
 
I thought someone would ask for this....I just woke up in the middle O the night, and I added everything to the render Q, so I should have something late tomorrow night....it would be sooner, but I have a shoot.

Huy Vu said:
Sigh, if only we have a camera actually capable of capturing that dynamic range. The HDR with tone mapping looks very nice. The reference adjusted is actually pretty good; you got back quite a bit of details without losing too much overall contrast. I would suggest showing the videos one after the other instead of squeezing them all on the same screen, it would be nice to see high res examples.
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dougspice said:
Really? I think it looks by far the worst. Uninteresting and washed out. Images are supposed to have contrast!
Click to expand...

The more I work with HDR the more I understand how to incorporate it, and one major thing I've found, based in no small part by your comment, is the need to blend in the original image with the HDR.

I'll have 58 seconds of video to show in about 3 hours, in which I leave the original videos opacity at 100%, the HDR without tone mapping at quite a low opacity,. and the HDR with tone mapping at an even lower opacity....the layering of these different kinds of images leaves alot of detail in the shot, a good amount of contrast, and although many of the colors are exxagerated I think the results are quite nice.

Stay tuned for the video.....
 
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