Will someone please shoot this and post the results?

[Brian Boyer]

Ahh, red brake lights and red traffic signals at night...the bane of digital cinema. Despite all that RED and Arri have accomplished, one of the few remaining tell-tale signs you're shooting digital is blown-out-to-white automobile brake lights, red traffic lights, red LEDs, etc. With the naked eye, and on film, depending on the plastic or glass covering and bulb technology used, the hot spot always blows out to either red with a red halo or yellowish orange with a red halo. When shooting digitally, these lights blow out to white with a pinkish red halo. This is unnatural. The only time I've ever seen a brake light look like that in real life is when the plastic covering is busted and the person used red tape or fabric to cover the hole with the white of the bulb shining through. What I'm referring to is most severe on shots where the red light in question is relatively close to the camera, less so when a few blocks away or out of focus. I know it may be a trivial thing but, since I've noticed it, it bugs me every time I see it and has me wondering if the sensors just haven't gotten there yet or are people just not paying attention to what they're doing. This is the case with all of the Alexa, Red One MX and Epic footage I've seen to date when shooting under these conditions.

This topic was somewhat touched on in a different thread a while back and someone surmised it may have something to do with the red channel having less dynamic range than the other two. I don't know if that's the case but no one ever did the test and posted the results. What I would like to see is someone who owns an Epic (Dino? Jarred, even?) shoot some close up, night time footage of engaged brake lights as well as typically framed street scenes with in focus, relatively close red traffic lights (or both in one shot) and properly expose for the lights to get that red and/or yellowish orange blow out with red halo. I understand doing that may leave the rest of the image (the actual subject of the shot) too dark but it seems that's where the magic of shooting raw might come into play. Everyone talks about how much you can push the image with raw data. Jim is always trying to get people to protect the highlights and use curves to raise the midtones to the desired levels. He says it so much I have to believe that, for whatever reason, people still aren't doing it and causing their images to suffer needlessly as a result. Is this one of those cases or are acceptable night time exposure levels and properly exposed brake lights in one shot too much to ask of the current sensor technology? Perhaps the noise will be too great. Should DPs simply be using more light on their subjects in this situation in order to prevent opening up as wide and causing the unnatural looking blowout? Whatever the case, I'd love to see what exposing for the brake lights looks like and just how much correction you can get away with before the image falls apart, if it's usable at all. I've never seen anyone deliberately attempt it so I don't know if it's possible or what it looks like.

I suggested an Epic because this test can be done with HDRx and without it. Perhaps HDRx with 18 stops of DR is just what the doctor ordered for this type of shooting. Perhaps it's not necessary and the MX sensor alone is up to the task, if handled correctly or with sufficient lighting.

And, just in case someone misunderstands this post, I'm not trying to start anything or nitpick. All gear has limitations. I'm just trying to ascertain where the gear's limitations stop and the user's limitations begin. Like many of you, I'm trying to decide between some flavor of Scarlet or the Epic-S. Until that happens and I can do tests myself, I have to ask the community for help.

I'm sure everyone would appreciate your efforts. Any takers?

 

[ericyoung]

I've noticed it too, and am bugged by it. Usually there are more pressing issues in those shooting situations though, so have just lived with it!

 

[George Butterfield]

I've noticed it too, and am bugged by it.

I saw this also in a film I was watching yesterday, it pissed me off, then, when the car took off from the stop .... the wheels were rotating backwards!

 

[ericyoung]

... then, when the car took off from the stop .... the wheels were rotating backwards!

That'll happen with film too though. Not something easily or usually worth correcting.

 

[Eren Ozkural]

Hey Brian,

2/3 through the fashion film I just shot on the Epic there's a few shots of cars at nights with closeups on brake lights etc. check it out HERE.

I find bright saturated yellow to be a bit trickier to get right with Red...but it's not an issue, just needs a little extra TLC in post.

 

[Brian Boyer]

Eren,

I actually watched that video before I posted and, to your credit, I didn't notice the brake lights, probably because they look more natural...that, combined with the quick cuts. I could be wrong but it seems your shots were helped out a bit by water on the lens or a filter (or both?). Either way, it's nice to know you can get most of that natural looking behavior back in post. However (and there's almost always a however with me), your highlights still blow out to white. Now, I guess that's just the name of the game with digital. All three color channels are described and defined by degrees of brightness ranging from black to white. If I'm not mistaken, when you run out of bits on the top end, everything turns white no matter what color it started out as. Overloaded blues turn white. Overloaded greens turn white, etc. I'm hoping someone can shoot this test and expose the brake lights to where the brightest part of the image never gets hot enough to turn white at all, keeping that nice yellowish orange glow you achieved in the horizontal lights on the right side of the brake lights. This way, you're not concerned with trying to retrieve this color information and correct exposure for the meat of the image.

Now, I'm going to start talking about something I know nothing about. It seems that, for future upgrades or advancements, incandescent highlight color protection could be implemented the way HDRx is now or added to an HDRx stream. I guess, in a way, HDRx kind of gives you that by giving you more dynamic range to work with so you have less chance of blowing out the highlights. But, once you do blow out, you blow out to white. I feel like I use too many commas. Since sensors are smart enough to know what color they're looking at, where proper exposure ranges are and at what point they overexpose, perhaps a track of data could be recorded that looks at the color of pixels just before clipping that can then be recombined with the main track in post to give you that color information back. So, even if you're overexposing you can get a nice blotch of the appropriate color instead of a white blotch. Or, maybe none of this is necessary if one takes more care when shooting.

And to George, Eric is right. I remember noticing the backwards rotating tires when watching cop shows as a kid in the 70s. You saw it quite a lot as they were keen on car chases and peel outs.

 

[Bruce Allen]

Now, I'm going to start talking about something I know nothing about. It seems that, for future upgrades or advancements, incandescent highlight color protection could be implemented the way HDRx is now or added to an HDRx stream.

That was the first thing I tested with Epic.

Highlight color protection definitely happens with HDRx and is fantastic for any still or slow-moving subject.

But when stuff moves, it gets tricky - because the highlight info is captured at a different time, it isn't in exactly the same place.

Now, you can use some retiming software to try to get the two exposures to line up better. But it doesn't always work 100% - especially because it's a naive morph.

If someone writes a plugin that can take a look at both frames and figure out the motion vectors and alignment from both the HDR and normal frames and then combines everything more cleverly, it might be possible.

Though even so there would be cases (foreground objects passing in front, etc) where it wouldn't work - or would work but in a temporally inconsistent manner.

Best case for now is:
1. if things don't move much and in a complex way, you already have highlight color protection with HDRx.
2. if there is complex fast motion, you have another VFX option to fix a shot. Though at the moment it's much easier to just track the car lights and repaint them

Bruce Allen
www.boacinema.com

 

[Bérenger Brillante]

Please Brian, let's put some space in your text, for non-english reader it's really harder to understand

 

[Brian Boyer]

Please Brian, let's put some space in your text, for non-english reader it's really harder to understand

I would like to accommodate you but I'm not sure what you mean. Do you mean space between lines of text?

Like this (and how Bruce did above)?

I suppose shorter sentences might also help?

Sorry, I tend to write everything like it's an essay. It's difficult to say all that I wanted to say in short, double-spaced sentences without the post becoming huge.

I'll try to do a better job.

If this helps, I'd like someone to shoot and post fairly close up R1 MX or Epic footage of automobile brake lights at night that don't blow out to white and see if they can raise the rest of the footage to acceptable levels without compromising the brake lights.

Also, I mentioned highlight color protection technology such that, when colors eventually do blow out, they blow out to the appropriate color and not white.

 

[ericyoung]

Hehe! Maybe not a space between every line if it's a huge post , but certainly shorter sentences and paragraphs helps readability!

 

[Marc Wielage]

With the naked eye, and on film, depending on the plastic or glass covering and bulb technology used, the hot spot always blows out to either red with a red halo or yellowish orange with a red halo. When shooting digitally, these lights blow out to white with a pinkish red halo.

It's possible to fix this to a point in color correction: pull a luminance key, confine the key just to the brake lights, add red to the whites, and match the red to the existing brake light color. Turn the effect on and off as the light level changes. It's doable.

I've routinely tweaked car headlights to be pure white when the client requested it, just to compensate for a white balance issue. This is pretty easy to do.

The best answer is, shoot a test, take it to post, and see what they can do with it. If it's only the brake lights, then I think it's fixable. If it's a giant neon sign in Times Square that's blown out, you have a problem.

 

[Joel Pfeiffer]

Wish I had a Camera to test this on, its very intriguing, I bet I can do it on my 7D if I give the other subjects enough key to match the brake lights, also you can tape a net fabric over the lights to cut down the luminance as well, otherwise fill the street with some 18k HMI's that should do the trick hehe....actually at the end on my music video shot on the mx a car with brakelights pulls right into frame, it blows out to a yellowy orange like, check it out, I can regrade it and see if its saveable. http://vimeo.com/25289027