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Cooke S4 Flair Issues


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#1 Gregory Irwin

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Posted 23 October 2009 - 11:30 AM

Hi all. I have only used the Cooke S4s twice in my career and have now experienced milky flares both times. I know that these lenses are highly touted for not flaring. I'm a bit at a loss due to doing everything possible to protect the lens from any extraneious light and am still having massive flares that milk out a large portion of the frame.

This has now happened three times on different Arricams on my current movie and the frustrating aspect is that the camera operators cannot see the flares through the viewing system and they don't show on video as well. The flares seem to be generated by the camera's gate with the light bouncing back through the lens' rear element off the emulsion and scattering throughout the lens barrel giving this milky, foggy effect. We know that we are not experiencing any light leaks in the camera bodies or mags. This definetly is a lens flare. Any thoughts, personal experience or advice would be greatly appreciated.

We are shooting 4 perf, 1:1.85 format with Arricam ST and LT cameras and Cooke S4 lenses and Kodak film.

Best,
Gregory Irwin
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#2 Stephen Murphy

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Posted 23 October 2009 - 12:50 PM

We are shooting 4 perf, 1:1.85 format with Arricam ST and LT cameras and Cooke S4 lenses and Kodak film.

Best,
Gregory Irwin



I've had similar flare issues when using Cooke S4's on Super 16mm but never on 35mm and Ive been shooting with them since they came out. Are you having the problem across multiple sets of lenses?
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#3 Gregory Irwin

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Posted 23 October 2009 - 02:14 PM

I've had similar flare issues when using Cooke S4's on Super 16mm but never on 35mm and Ive been shooting with them since they came out. Are you having the problem across multiple sets of lenses?



Hi Stephen,
I have only one complete set of the Cookes and we've had the issue mainly with the 75mm and the 32mm. Our Optimo zooms have had no flare issues.

GI
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#4 Stephen Murphy

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Posted 23 October 2009 - 04:07 PM

Hi Stephen,
I have only one complete set of the Cookes and we've had the issue mainly with the 75mm and the 32mm. Our Optimo zooms have had no flare issues.

GI



That's really strange - the 75mm is my workhorse lens for close ups and ive never come across the problem on 3 or 4 perf 35mm.
I'm sure its stating the obvious but is it possible to switch out the primes for another set?
Out of curiosity are all the S4's in your set S4i's or are any of the lenses without the i interface - with a smaller barrel diameter at the iris ring.?
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#5 Gregory Irwin

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Posted 23 October 2009 - 05:24 PM

That's really strange - the 75mm is my workhorse lens for close ups and ive never come across the problem on 3 or 4 perf 35mm.
I'm sure its stating the obvious but is it possible to switch out the primes for another set?
Out of curiosity are all the S4's in your set S4i's or are any of the lenses without the i interface - with a smaller barrel diameter at the iris ring.?



We just have the plain, old S4s with the very large rear elements. Otto Nemenz (our rental house) says it's a common problem with the lens/film gate combo. Terrific. We are currently powder coating new gates to see if that eliminates our problem. Stay tuned...
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#6 Stephen Murphy

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Posted 23 October 2009 - 05:31 PM

We just have the plain, old S4s with the very large rear elements. Otto Nemenz (our rental house) says it's a common problem with the lens/film gate combo.


Really? Presume you're shooting open gate? Im usually shooting S35 2.35:1, shot with the S4's and the S4is and never seen it. please do keep me posted.
S
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#7 Gregory Irwin

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Posted 25 October 2009 - 11:09 AM

Really? Presume you're shooting open gate? Im usually shooting S35 2.35:1, shot with the S4's and the S4is and never seen it. please do keep me posted.
S



Yes on the open gate. The other factor in this is we get more than a typical gate flare from having practical, usually specular light sources inside of full aperture but outside of the frame lines. In other words, when a specular light source comes into view but not into frame, we have experienced this "wash" like flare. Once the light source is in frame, the flare ceases and the Cookes perform as expected. This is where it gets dicey since we always have light sources close to the frame lines.

This is why I'm at a loss on this because we are performing everyday practices that we would normally do with any Panavision or Zeiss lens. I have repeatedly been told that nobody has experienced this before yet I know that I cannot be the first and only one. Finally, after much prodding, it starts to be revealed that this is a problem with the Cookes. So now I'm trying to move on to finding a solution to combat this.

GI
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#8 Stephen Murphy

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Posted 25 October 2009 - 11:26 AM

Yes on the open gate. The other factor in this is we get more than a typical gate flare from having practical, usually specular light sources inside of full aperture but outside of the frame lines. In other words, when a specular light source comes into view but not into frame, we have experienced this "wash" like flare. Once the light source is in frame, the flare ceases and the Cookes perform as expected.


What you've just described is exactly what happens when I've shot with them on Super16mm and i was always under the impression that it was bounce back from the gate due to all the excess light bouncing around from the larger rear element. Really puzzled why you'd have it on 35mm. Have the black powdered gates helped at all?
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#9 Gregory Irwin

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Posted 25 October 2009 - 03:08 PM

What you've just described is exactly what happens when I've shot with them on Super16mm and i was always under the impression that it was bounce back from the gate due to all the excess light bouncing around from the larger rear element. Really puzzled why you'd have it on 35mm. Have the black powdered gates helped at all?



I don't have the powder coated gates yet. Why would super 16 be different from super 35? The percentage of the negative area is similar, isn't it? But I think that you are correct regarding the large, rear element bounce back.

G
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#10 Stephen Murphy

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Posted 25 October 2009 - 03:39 PM

I don't have the powder coated gates yet. Why would super 16 be different from super 35? The percentage of the negative area is similar, isn't it? But I think that you are correct regarding the large, rear element bounce back.

G



As i understand it Cooke S4's (and in theory Primos, Ultra Primes, master primes etc) all project a larger cone of light then a S16 mm neg/gate would receive compared to the smaller cone of light a S16mm Lens would project onto the same S16 neg/gate .The excess light from the 35mm lens can bounce around off surfaces within the camera that aren't used to receiving light and cause milky flares and/or a lowering of contrast.
Having said that this shouldn't be a factor with a 35mm lens on a 35mm camera but if this is the same problem then i would have thought the black powdered gates would solve it. Out of curiosity have you spoken to Cooke?
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#11 K Borowski

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Posted 25 October 2009 - 04:16 PM

What you are describing is more akin to halation than actual flare, no?


Am I reading you correctly that you think the light is going through the lens, through the film & it's rem-jet backing, bouncing off the reflective pressure plate, and then bouncing back into the lens?

Or do you mean something else?



BTW, can you post a short clip or a freeze-frame of the problem you're experiencing?

Edited by Karl Borowski, 25 October 2009 - 04:18 PM.

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#12 Gregory Irwin

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Posted 25 October 2009 - 06:38 PM

What you are describing is more akin to halation than actual flare, no?


Am I reading you correctly that you think the light is going through the lens, through the film & it's rem-jet backing, bouncing off the reflective pressure plate, and then bouncing back into the lens?

Or do you mean something else?



BTW, can you post a short clip or a freeze-frame of the problem you're experiencing?

It could be bouncing off of the pressure pad but that's not the thinking at this time. It's more likely that it's reflecting off of the emulsion itself.

Unfortunately, all of the images are property of Paramount Pictures and they will not allow me to post any clip. Too bad for that would be helpful.

G

Edited by Gregory Irwin, 25 October 2009 - 06:41 PM.

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#13 Gregory Middleton

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Posted 26 October 2009 - 01:18 AM

I have encountered a similar phenomenon shooting 3 Perf Panavison with Primos. Lightsources just outside of 1:1.85 but inside film area would produce what looked like a flare, but only when just in that area. If camera was tilted up or down you could see flare disappear the reappear.
We never managed to eliminate it completely. I think powder coating the insides might help.
Are you Super 35 or regular?
I took a few out in the DI later. If its any consolation, it did not kill the film.
Being careful with light sources (practicals) in the danger area might be your best short term defense.

g



It could be bouncing off of the pressure pad but that's not the thinking at this time. It's more likely that it's reflecting off of the emulsion itself.

Unfortunately, all of the images are property of Paramount Pictures and they will not allow me to post any clip. Too bad for that would be helpful.

G


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#14 Mike Panczenko

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Posted 26 October 2009 - 12:50 PM

I did a job a few years ago with Primos where the 1st made sure all of our lenses had the net rings on the back- they need to be RF (rear filter) lenses. I don't remember if it needed the rings themselves, or just the RF capability, but it limited the beam of light coming out of the rear element, and it cut down on flares when shooting Super 35, by preventing light from bouncing around.

Finding a way to duplicate this in PL might help solve the problem?
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#15 Phil Rhodes

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Posted 26 October 2009 - 01:30 PM

All I can add is that I have used S4s on a couple of tests of those spinning-groundglass contraptions for video cameras. I generally specified them because they ought to be so good as to be invisible for the purposes of an experiment in that context, and particularly because of their reputation for being flare-free in a situation where you're looking for exactly that sort of optical oddity. The size of the "gate" in that case tends to be full aperture (so as to be able to use the thing efficiently with 4:3 video cameras). While we spent quite a long time waving pea lights around in front of it looking for exactly these sorts of issues with the ground glass causing odd effects, I don't recall seeing anything untoward.

Possibly not that directly helpful, I must admit, but there it is.

P
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