I have a friend who is deeply into photography. So one day he starts asking me about HDR (High dynamic range) video. I frankly am at a loss having only a passing acquaintance with photography in general (it's one of those hobbies I would like to do, but haven't the time or money to be serious). So I started reading up on it. Then I found out that you can do HDR video and I thought "well isn't that something." Actually, there might have been some form of vulgarity in my thoughts, which I will spare you from.
HDR, high dynamic range (imaging), is a set of techniques that allow for some pretty fantastic images. When I mean fantastic I mean both in the "wow factor" as well as in "unrealistic" because it takes a series of photos, and combined them into something the human wouldn't normally see. Of course if something like this can be accomplished with digital images, it was only a matter of time before it would be applied to video. and 3D imagery as well. So HDR 3D video must be on the way.
It's still in its infancy for video so the majority of things I'll talk about here apply to still images, but are making the move to video.
This image, below, is taken from the Wikipedia page on HDR. It's author is Igor Irić and I included it because, it's in Brno, the second largest city in the Czech Republic (the country in which I live). What are the odds?
This image is actually a tone-mapped HDR image. For more on that read the Wiki if you please.
What Is HDR (High Dynamic Range)?
Imagine taking the coolest pieces of an overexposed image and an underexposed image (or a series of them) and then weaving them together into something while still the same subject, a totally different result. On the Wikipedia page for HDR you can see a 3 and 4 image result. In speaking with my friend, he stated that he uses 5-7 images and his camera can put them all together automatically.
Essentially it all depends on the light intensity and has been around since 1850, believe it or not. Since then it has been evolving and is now available in some mid to high-range digital SLR cameras.
Dynamic range is measured in EV, exposure value, between differences in the brightest and darkest areas of a photograph. An EV unit is a doubling of the amount of light coming from something. There's a whole lot of math behind it and it's all explained elsewhere so I won't rehash that.
Aside from looking different, HDR images store a lot of extra information about the amount of light reflecting, luminance, of objects in the photo. Usually all of those values aren't able to be shown on a standard computer monitor or photographic paper.
Now you know what that Merge to HDR function is in your Photoshop menu (if you've got CS2 or higher).
The two images on the right are by that friend of mine I mentioned. They're used with his permission to show you some of the capabilities of HDR. He generally uses 5-7 exposures (if I remember correctly) and bracketing (see Wiki page). They're pretty spiffy I'd say. (Hey Petr, made ya famous! Well, sort of.)
How Does HDR Apply To Video?
Well, at present it doesn't quite yet. But if you read my Reel weekend article and saw the super cool dual lens 3D camcorder, you know that it could rapidly be applied to video. In fact, thanks to a group of clever individuals, it has. Soviet Montage Productions, reported by Engadget, used two Canon EOS 5D Mark II DSLRs and a beam splitter so that each camera saw the exact same image from the exact same angle as opposed to 3D video where you need that offset of the cameras to get the depth. I'm trying to get a hold of those guys for an interview about their video and technique. I don't know that this is the first HDR video but it might be the first made in this fashion (see end for others).
Essentially, from what can be gathered, the two cameras were set up differently. One was underexposed while the other was overexposed and both were pointed at the same subject matter. Now that would generally cause a visual offset, hence the beam splitter which allowed both lenses to see the exact same image.
It's pretty fancy stuff and any sort of digital video camera that's going to do this would either have to be set up to take 60 frames per second or more and alternate between over and under exposure (quite a technical hurdle I imagine) or have a similar setup to the Soviet Montage one where it would have two separate imaging processing units that feed off of the same image. My setup would probably create some funky ghosting effects so there doesn't seem to be any way to do it without two lenses.
The Future Is HDR Video In 3D?
Since I'm in a prognosticating mood, I thought I would extrapolate this out to the future and include the current hot trend in multimedia entertainment, 3D. Since 3D is using two lenses already, to get the 3D offset, you would then have to have four lenses for an HDR 3D setup (unless you get the double quick under/over exposure I talked about before). So you would then have left under and over exposures and right under and over exposures and that would give you a massively cool hyper-realistic HDR 3D video. Now, both the left and the right would have to have beam splitters so that the under/over exposure processing units got the exact same information. Whew! That sounds like a beast of a camera. But really, I can't wait for someone to build one so we can see what HDR 3D looks like. It's gonna be frickin awesome I bet.
That's A Wrap!
You'll notice, I called it hyper-realistic. And I mean that in the more than realistic sense as, to my eyes anyway, HDR images look doctored or unnatural. Now I know people say that HDR is meant to view images the way the scenes really were, but I just don't see it that way. Our eyes can't do over and under exposure at the same time so I don't truly believe that we see in an HDR range. In fact, most digital cameras 'dumb down' the visual information to a human eye level. So that means, to me anyway, that standard digital cameras, with no special or post processing, are creating images like we see the world. HDR is just a really cool way for us to see things we see every day. It all has a sort of fantasy feel to it when I view images and that video, for me anyway. Perhaps my view of the world is just tinted by other things.
After writing this article, I found the video below as well, it was published 5 months ago it seems by Matthew Gorveatte.
There's no information on how he did it. It only mentions his 'new HDR HD video camera.' It looks more like some sort of trick than real HDR but again, it's just my opinion.