June 16, 2011

A Perfect Video Demo of Why RED's HDRx is a Game-Changer

I just got through watching Doug Liman's Fair Game, and was impressed with how the film dealt with the Valerie Plame affair without dumbing it down -- it was a refreshingly "adult" Hollywood feature. However, what I wasn't impressed with was the RED cinematography, with Liman himself serving as DP. It looked fine, but it didn't look great, to my eye. In camera tests to date we've seen that the RED has plenty of shadow detail but lacks the highlight details of film, and it's the slightly blown-out look of skin tones and other highlights that has has me "meh"-ing some RED cinematography. Enter RED's game-changing exposure hack, HDRx. The following video was posted to the Cinematography Mailing List a while ago, but it's a great explanation of HDRx in action on the RED EPIC, and also offers a glimpse of Assimilate's post-production software SCRATCH at work:

At 4:25 you can see exactly the kind of blown highlights that have irked me in previous RED footage. Will HDRx fix this complaint? It certainly seems so (the alternative with non-HDRx cameras is to underexpose, but then you risk losing shadow detail). For indies who don't have a raft of lights, the above shot is a good example of HDRx's utility -- to properly expose the subject and the beach, with most cameras you'd need some powerful daylight-balanced lights on the subject. And a grip truck. And a generator. But with HDRx you can get the shot with just the camera, saving indies time and money. This is not to say that you no longer need lights, but for specific situations like this one, you might be able to get the setup in a fraction of non-HDRx time.

HDRx adds up to three stops of dynamic range to the RED EPIC (and forthcoming EPIC-S), which takes the 13-stops of the EPIC all the way up to a world's-best (better than film, and better than digital leader ARRI ALEXA) 17+ stops.

Thanks go out to Blair Paulsen for a great demo. You can find some uncompressed TIFF files and more explanations over at Local Hero Post.

[thanks, Simon]

Your Comment


Can't stand Doug Liman as a director and now as a DP. The cinematography in that movie was utter shit, not only from a "look" perspective but also from a shot perspective. Some of the shots were so random and unneccessary. I just didn't get it.

June 16, 2011 at 1:23PM, Edited September 4, 10:54AM


You do realize Doug Liman is half blind.
Seriously..he has vision problems..that's
why half of Swingers is out of focus.
He also suffers from the Soderbergh
delusion/complex: the belief that
they are DP/operators who improve
their film looks. Truth is they ruin them.

June 16, 2011 at 3:10PM, Edited September 4, 10:54AM


Yeah, hdrx is really the biggest feature coming on epic and scarlet in my opinion. Although, i heard 18 stops quoted several times (i saw your 17 +, i'm just saying, to clear up somethings, either on my end or someone else's),. Even though I've defended epic several times, i'm the first to admit that i don't care much for straight up RED footage without at lest mx, much preferring the arri d21 even to it, but i think they truly have changed the game with epic and will even moreso with scarlet.

There's an amazing couple of youtube videos that are a bit less "pro" in their examples of hdrx but truly show just how "showy" it can be.




Just absolutely stunning to me.

Not to mention, i've heard several gushings now of how the spiderman footage looks

June 16, 2011 at 4:28PM, Edited September 4, 10:54AM


Just so I'm not going insane here. If you can capture RAW information from a sensor, wouldn't you have "built-in" HDR? If you grade a RAW file, would all the information just "be there" already?

Also, while I do love HDR, is it really that amazing or an excuse for holding up the camera delivery dates? The IPHONE has HDR, and I use it all the time. It's great, but it's also already here in the most consumerist form possible.

Sanity check anyone?

June 16, 2011 at 6:18PM, Edited September 4, 10:54AM


RAW and HDR are two different things.

They're not "holding up camera delivery dates," a little thing called a Tsunami knocked out a portion of their (and many electronic manufacturer's) supply chain.

HDR is a lot more straightforward with still images. Combining two exposures is a lot more complicated with motion picture cameras (if it was easy, a lot more cameras would have the feature already).

June 16, 2011 at 8:15PM, Edited September 4, 10:54AM

Ryan Koo

By the way KOO, i wasn't responding to you, i was responding to the initial question

June 16, 2011 at 8:16PM, Edited September 4, 10:54AM


Thanks, Brennan. I wasn't clear on the differences, and you made it clear. You get a medal made out of thank you.

I believe the ARRI Alexa actually uses two sensors, one tuned for highs and one for lows to achieve their HDR. I suspect that Red would just use slower frame rates when allowing HDR mode, capturing higher frame rates in the background, one for the low and one for the high.

Curious about what you've heard?

RE: Koo, not being an insensitive bastard about the tsunami, RED has mentioned specifically HDR was one of the holdups. You also get a medal made out of than-you and puppies for this great blog of yours.

June 17, 2011 at 6:29PM, Edited September 4, 10:54AM


hahaa thank you for my medal made out of thank you.

That's the first i've heard about the alexa, i don't think that's quite spot on. I think it has 1 half stop more dynamic range than the epic does natively (but even this is debatable). And Frame Rate and Shutter speed are not quite the same thing.

The frame rate is number of times your sensor is exposed to your image in 1 second. 24p(progressive) is the common frame rate for digital because it mimics the 24 frames of film per second in film capture cameras. But news channels shoot in 30p or 60i (same amount of full frames; too long and off topic to explain fully), and this gives it a different look because it captures 6 more frames per second than 24p mode does. The less frames the more your mind fills in between and creates a blur. 24p mimics very closely how we see even our everyday reality.

What hdrx does is adjust shutter speeds, even though the frame rate is the same. The shutter speed is how long each individual frame (of the 24 or 30 that you would be shooting per second) is exposed to light coming in. The most common setting is to shoot at 1/48th of a second shutter speed for shooting at 24p and 1/60th at 30p or 60i. So, the slowest shutter speed you could go would obviously be the inverse of your frame rate. Any slower would overlap frames.

Obviously if you expose a frame to light for a shorter amount of time, there isn't gonna be as much light hitting the sensor (just scientifically). It also means the faster you expose your frame, the less "motion blur" there will be sense the sensor can "freeze" action by taking a quick quick snapshot at a high shutter speed. Motion appears more blurry and smooth at the slower shutter speeds, and choppy and quick at the high shutter speeds. So, this obviously would look a little different if you have two different shutter speeds. This is what red calls "Magic Motion." It does look incredibly life-like, but it isn't different than normal motion blur, so they've allowed their post-production tools to be capable of making hte motion blur more normal by blendin the two tracks manually.

I know that's super involved and complicated, but i hope it answers some of your questions

June 17, 2011 at 9:05PM, Edited September 4, 10:54AM


also, this hdrx mode allows it (the epic) to go from about 13 or 13.5 stops (the alexa is 13.5) of dyamic range, all the way up to, if i have my numbers right, 18 stops of dynamic range. Totally unheard of and revolutionary. This pushes is way past alexa in terms of image quality (at least in the dynamic range aspect, which is one of the most critical parts of the final look in any image aquisition)., but in terms of "color science" or how they make their camera's processors define "colors," the two are heavily debated.

June 17, 2011 at 9:09PM, Edited September 4, 10:54AM


also, i meant to say that the two different shutter speeds WOULD NOT make the motion blur normal, hence, it may need to be corrected if you don't like the look of it

June 17, 2011 at 10:12PM, Edited September 4, 10:54AM


Well, yes and know. RAW is going to give you the most possible information from any given still or peice of footage you shoot because it leaves of all metadata such as ISO & Color Temp (White Balance), which are actually processor functions. However, you still adjust the sensitivity of the sensor itself with both your shutter speed and your f stop exposure. If you stop down and have a high shutter speed, you're still going to have a darker picture with a lot of detail in the highlights becuase you've only given the sensor that amount of light. Same thing with over exposing. Your sensor still has limits, even with RAW. But, HDRx allows you to (somehow) capture 2 streams simultaneously with one stream having your set shutter speed, and the other having a faster shutter speed to preserve more details in the highlights. This is what causes the differnce in motion blur described in the video above.

So, in short: RAW gives you the most information you can possibly haved based on how you've exposed your scene/subject; hdrx allows you to broaden that horizon.

June 16, 2011 at 8:15PM, Edited September 4, 10:54AM