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HDR Video a Reality
akaru writes "Using common DSLR cameras, some creative individuals have created an example of true HDR video. Instead of pseudo-HDR, they actually used multiple cameras and a beam splitter to record simultaneous video streams, and composited them together in post. Looks very intriguing."
C&P from the linked page (assuming a /.'ing imminent)
HDR demo @ http://vimeo.com/14821961
Press Release:
HDR Video A Reality
Soviet Montage Productions releases information on the first true High Dynamic Range (HDR) video using DSLRs
San Francisco, CA, September 9, 2010: Soviet Montage Productions demonstrated today the first true HDR video sourced from multiple exposures. Unlike HDR timelapse videos that only capture a few frames per minute, true HDR video can capture 24 or more frames per second of multiple exposure footage. Using common DSLRs, the team was able to composite multiple HD video streams into a single video with an exposure gamut much greater than any on the market today. They are currently using this technology to produce an upcoming film.
Benefits of Motion HDR
HDR imaging is an effect achieved by taking multiple disparate exposures of a subject and combining them to create images of a higher exposure range. It is an increasingly popular technique for still photography, so much so that it has recently been deployed as a native application on Apple’s iPhone. Until now, however, the technique was too intensive and complex for motion. Soviet Montage Productions believes they have solved the issue with a method that produces stunning–and affordable–true HDR for film and video.
The merits of true HDR video are various. The most obvious benefit is having an exposure variation in a scene that more closely matches the human eye–think of filming your friend with a sunset at his or her back, your friend’s face being as perfectly captured as the landscape behind them. HDR video also has the advantage of reduced lighting needs. Finally, the creative control of multiple exposures, including multiple focus points and color control, is unparalleled with true HDR video.
“I believe HDR will give filmmakers greater flexibility not only in the effects they can create but also in the environments they can shoot in” said Alaric Cole, one of the members of the production team, “undoubtedly, it will become a commonplace technique in the near future. ”
Contact:
Michael Safai
Soviet Montage
201 Spear Street #1100
San Francisco, CA 94105
1 415 489 0437
mike@sovietmontage.com
Those who can, do. Those who cannot, sue.
Wiki explains it well:
is a set of techniques that allow a greater dynamic range of luminances between the lightest and darkest areas of an image than standard digital imaging techniques or photographic methods.
And their picture is a great example. If you expose the building well, the clouds are washed out. If you expose the clouds well, the building is dark. If you take pictures of both equally exposed then merge the photos, you now have a properly exposed building along with a properly exposed sky giving thus giving you more dynamic range. Think of it like instead of going to the lunch buffet and cramming everything into one plate, you go up to the buffet three times with three plates: one for salad, one for main course and one for dessert. With a little processing (trips) you end up with more range (food variety).
Wasn't the first HDR video camera back in 1993? Granted, they called it Adaptive Sensitivity back then.
The technique is promising, but the provided example video does not demonstrate a true advantage it has over conventional cinematography. They filmed with two cameras, one overexposing one underexposing, but they don't have one with the right exposure to compare with the composed HDR images. The city scenes are filmed at daylight, without any areas of high contrast that would make a high dynamic range necessary. The same with the people example, they even overdid it to give it a vibrant effect, making it more of an artistic tool than capturing shadows and lights naturally.
They should make a short film with city nighttime and desert scenes, that should be impressive. They should also contact director Michael Mann, he would jump at the opportunity to film HDR.
HDR looks so unreal even if at times aesthetically pleasing. Their "more real" filter didn't do the scene much justice too.
Was the guy supposed to look that way?
The video was not very good at all, so I'm not sure why it is a big deal. The video of the guy was more HDR than any other part, though it was very strange.
Take a look at some of the HDR photos on Flickr http://www.flickr.com/groups/hdr/pool/. They give much better and proper example of HDR.
That's one of the problems with HDR photography. The light to dark transitions just don't look quite right and so the scene has an 'unreal' appearance. Either washed out or cartoonish.
You see that all of the time in still HDR photography and I think it has to do with the limitations of the final media - movie screens, paper, computer screens - that do not reproduce the eye's ability to deal with contrast well. In prints, you can work with this and minimize but not completely remove the effect. I imagine that they could tweak their algorithms a little better but Internet video isn't a particularly high quality visual experience in the first place so there well be some limitations in how well they can do it.
Faster! Faster! Faster would be better!
The bright spots are indeed an artifact of the HDR process -- partulcarly the tone-mapping algorithms. On its own, HDR is basically a method of capturing intensity values that would otherwise fall above or beneath the threshold of a camera's sensitivity. The problem is, when yo do that you end up with image data that can't be completely represented within the gamut of a printer or a screen. You could simply display a "slice" out of the data, which results in a regular images at whatever exposure setting you've chose, or try to "compress" the tone values into your available gamut, which results in a washed-out appearance. This is where tone-mapping comes in. What tone-mapping does is try to compute the correct exposure levels on a per-pixel basis, by comparing its intensity relative to nearby pixels. Ideally, this results in shadows being brightened to the point where you can see detail in them, and blown-out highlights brought toned down (analogous to "dodging" and "burning" in terms of old-school darkroom film processing -- the dynamic range of film is much higher than that of photo paper).
In practice, though, you end up with weird highlights around dark areas, like the ones you saw around the man's arms, because the tone-mapping algorithm is trying to maximize the local contrast in the image. It's brightened up the coat, and so it also brightens nearby pixels to compensate for the reduction in contrast. Some people try to adjust the algorithms to minimize this effect, while others try to maximize it for dramatic effect, or even an oversaturated, impressionistic look -- it's largely an artistic choice, though when done badly it can also be a sign of amateurism. Still others will manually composite multiple exposures to get the benefits of HDR imaging while avoiding its side effects entirely,
The Wikipedia article on tone-mapping goes into great detail on the different approaches to HDR photography, if you're interested.
You can get HDR to look 'fine' or whatever adjective you want to use. It's just hard. The tone-mapping software/settings that many people use will just go and create doll skin and haloes everywhere. But if you do everything well (hard work!) you can get some really cool looking stuff. For example...
http://www.flickr.com/photos/swakt1/2322363690/
http://www.flickr.com/photos/swakt1/2322366898/in/photostream/
http://www.flickr.com/photos/ten851/4972637653/in/pool-hdr
Somewhat like many other art techniques, when best used, you barely notice it at all. And that is the most important thing to remember. HDR + tone mapping isn't just a technology, it is an art. Being able to capture video in 3 different stops at once is great, but it'll still look like crap unless you treat it with respect and give it the effort and time needed.
Remember, HDR + tone mapping is just trying to create a low dynamic range image on a low dynamic range display that LOOKS something like what your mind perceives in a high dynamic range environment. Obviously, that's kinda hard, especially since the human eye can change its sensitivity as it focuses on different parts of a scene in real life, but not really when looking at a computer screen or print.
Incorrect, it's true HDR recording. The process of viewing it on LDR/SDR monitors is tone-mapping, which over the years has been tuned to represent the best known science of what the eyes actually see at once - our retinas already make us susceptible to only being able to view certain ranges of light at a time.
In other words, more information is being recorded than your eye can see at once, and you're complaining because when you see it, all that information isn't there? That's a pedantic, unsolvable contradiction.
A true HDR *display* (unfathomably difficult to imagine, I won't begin to go into the problems with the source for all the light being in one location, while other light is also hitting the eye from the real-world outside of the display, making visual processing of the HDR display massively erronous), would offer no advantage to a tone-mapped image, as your eye still can't see more than a certain range at any given time.
Tone-mapped SDR images actually produce images with more visible detail *at once* than the eye can distinguish *at once*. Sure, the eye can do things the still image can't, like focus somewhere else, shield out certain bright or dark parts, and readjust automatically to what you're now viewing - I'm not claiming tone-mapping will ever produce as much variance as the eye is capable of - but it DOES bring to light more detail in HDR recorded scenes than the eye could otherwise see at once looking at the same scene.
"The true measure of a person is how they act when they know they won't get caught." - DSRilk
They used more of a dragan-ish style of HDR here. They set it up to preserve local contrast at the expense of actually mapping brightnesses linearly. That's why it looks so freakish: some tones are brighter than other tones that should have a physically higher brightness.