Home of Professional Cinematography since 1996

RED IR Hands on in Hannover

Published : 02/11/2009


I posted about filming a fire eater at night in my message about the D-21 this test revealed a really serious problem with the RED.


Now OK in reality this will probably not be a problem for you in normal filming, I can only remember filming a fire eater once before and that was around 15 years ago!


So what was the problem?


Massive flare's all over the image, it looked like some kind of fogging.


We couldn't figure out what it was, flare from the hot back-light? No, it wasn't there all the time, lens issues, doubtful we were using Master Primes, then it dawned on us, it only happened at the brightest/hottest parts of the fire eaters performance.


We must be looking at an IR issue. We looked at the individual levels later in the Film Master suite and sure enough it was the red channel that was showing the worst contamination. Unfortunately we didn't have time to shoot extended tests of this phenomenon but I will try to in the near future. Of course if anyone else has seen anything like this...


Cheers


Geoff Boyle FBKS
Cinematographer
EU Based
Skype geoff.boyle
mobile: +44 (0)7831 562877
www.cinematography.net



> We must be looking at an IR issue.


Not to contradict, but could it have (also) been reflections in the OLPF/IR package?
Tim Sassoon
SFD
Santa Monica, CA



>> Not to contradict, but could it have (also) been reflections in the OLPF/IR package?


Not a contradiction ...


It's still an IR related problem!
Oh and yes it could well have been a OLPF/IR issue but as it only occurs in extreme IR conditions I kinda see it as an IR problem.


Cheers


Geoff Boyle FBKS
Cinematographer
EU Based



>> It's still an IR related problem!


I think I'm with Tim on this one. I've not seen IR be a serious issue on the RED without a bunch of ND in front of the lens. And under tungsten light the IR spills I've seen have affected the blue channel, not the red.


http://provideocoalition.com/index.php/aadams/story/red_hot_mirror_shoot_out/


And I believe people here have commented on this same issue before,
where they've had to cut a mask and place it behind the lens in order to reduce reflections.
Unless you saw fluctuating color saturation in the veiling (red or blue fog) I think it's reflections.
Art Adams | Director of Photography
4 1 5 . 7 6 0 . 5 1 6 7



The DALSA Origin had that problem as well, in spades. It was DEFINITELY an IR problem. Flames, gunfire, all of them had that tell-tale "fogging glow" especially when the background was dark.
We did not find a filter (hot mirror, IR cut-off, etc) that ever fixed the issue. Has anyone found a solution? The purple/orange glow was definitely not a good look...


Alan Lasky
People's Republic of California



I've encountered the same issue on a Red Feature last year in Michigan during a Night scene. I did try a Tru-Cut IR to try and solve it but couldn't due to the fire/flare's intensity even when stoppinging down to T2.8-4 which would minimize the issue.


We were shooting Cooke S4i Primes.


Could this be some cross talk / CMOS fringing issue?


Dane Brehm
Binary DIT
San Francisco



>> I think I'm with Tim on this one.


It was a possibility that I'm far from sure was correct; I just thought it was worth consideration. So I'm not sure _I'm_ with me on that one
Tim Sassoon
SFD
Santa Monica, CA



Art Adams writes :


>>I've not seen IR be a serious issue on the RED without a bunch of ND in front of the lens.


But have you actually photographed fire with the RED? -- with and/or without ND?
Dan Drasin
Producer/DP
Marin County, CA



>> But have you actually photographed fire with the RED? -- with and/ or without ND?


No I haven't. But I do remember people talking on the old CML lists about having reflection issues between the sensor and the back of the lens.


I guess fire is hot, but how could it give off more IR energy than the lights we use on a daily basis? I've aimed the RED into hot lights and not seen anything like what is being described.


Oh well, one more test to do. I'll have to see if Videofax or Chater Camera will let me bring over some gasoline-dipped torches.


Art Adams | Director of Photography
4 1 5 . 7 6 0 . 5 1 6 7



>>But have you actually photographed fire with the RED?


Like a light clicking on, it just occurred to me that we've been overlooking the obvious. How could we be so stupid, so obtuse? The answer to the conspiracy has been in front of our noses the whole time without anyone seeing it.


The camera's hyper-mega-secret real name is - "Infra-RED"!


Tim Sassoon
SFD
Santa Monica, CA



Geoff Boyle wrote:


>>I posted about filming a fire eater at night in my message about the D-21 this test revealed a really >>serious problem with the RED.
>>Now OK in reality this will probably not be a problem for you in normal filming, I can only remember >>filming a fire eater once before and that was around 15 years ago!


Funny thing there Geoff. I just filmed a fire eater on Tuesday in Montevideo, Uruguay. I didn't have any fogging or hazing problems at all. Neither did I on all of the massive fiery explosions at the end of "Quantum of Solace". We shot on film! 35mm, 5219, Master Primes and Cooke S4s. Full range of tones, color, latitude, sharp, lovely. Of course on my last red show I did have moiré problems when shooting a patterned concrete building, rolling bars when plugged in to the generator where the lights were plugged in and also lots of fixed Bayer pattern noise in underexposed areas of a full daylight scene. But it is getting better all the time.


I'm sure that the sensors and algorithms will catch up to film sometime in the near future. I really do hope so. And I look forward to seeing what the new Red cameras will be able to do, as well as the new Arri's, especially the nice one with the optical viewfinder. And hopefully the digimag for the Penelope will be up there too.


Roberto Schaefer, asc
Venice beach, ca.



I just finished another 2 day MV shoot (on RED)and used the Rosco IR filter this time-hopefully we'll see benefits to doing so...post - production next week(on Scratch)


Best,


John Babl
DP
Miami



We've shot flames a number of times on stage for food/table top shots with the RED. No problems ... but we're usually at a fairly deep stop, balanced with our table top lighting. With 400/500 iso film we shoot flames at 16 to get good rich colors; with the RED we're at around 8 ... using a Schneider 1/2 CTB filter and 160 iso.


Mako, Makofoto, S. Pasadena, CA



>> balanced with our table top lighting.


Which is why you wouldn't have a problem.


We were testing extremes, a Master Prime wide open at T1.3 and a fire eater at full blast.
The scene was lit with daylight backlight at T1.7, bounce tungsten side-light at T0.7.7 and a daylight kicker at T0.7.7, I didn't get the level of the flames but I will have notes on this soon.
Cheers
Geoff Boyle FBKS
Cinematographer
EU Based



What's the point? Why would one shoot flames that wide open? Reminds me of 1.4 night explosions where everything just goes white on film ... but that's not what the eye sees ... so why shoot it that way? Ugly "effect."


Mako, Makofoto, S. Pasadena, CA



>>Reminds me of 1.4 night explosions where everything just goes white on film…


Seen a lot on television projects. Fire always looks best at daylight exposure levels.
PM's always ask why we want so much additional lighting for NIGHT-EXT practical fire.


David Perrault, CSC



>> What's the point? Why would one shoot flames that wide open?


The point is to test the extremes, see what happens, hey! If we all avoided extremes then nobody would have sailed off the edge of the world and you wouldn't be living where you live! Also episode 2 of Flash-forward did have an explosion with flames that bright.


What happens if I have a sequence with an explosion and I expose "correctly" for the flames in the majority of the shots but then cut to a shot that only has a small portion of the flames in but the flames light up a dark area that contains information that is vital for the story?


If I hadn't pushed the tests then I wouldn't be aware that one of the cameras I tested was going to cause me pain if I did that and I'd then have to explain to a director why the shot was f'd up and not have a clue.


Cheers


Geoff Boyle FBKS
Cinematographer

 

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