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CP-16R Super 16 Conversion


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#1 Robert Hughes

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Posted 02 June 2005 - 02:31 PM

I've recently acquired a CP-16R camera with the bow-tie mirror shutter. It needs an overhaul before I can use it, so I plan to send it to Whitehouse or Visual Products for a rebuild. Since I've got to get it fixed anyway I'm considering having Visual Products put in their Super 16 conversion and a PL mount.

Does anyone have working experience with Super 16 conversions of the CP-16R? Especially considering the reputation for smearing with the bow-tie mirror shutter, would a Super 16 conversion exacerbate the problem? What about resale value of a converted camera - would the increased value balance out the cost of conversion?
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#2 Matt Pacini

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Posted 02 June 2005 - 06:48 PM

I've thought about doing it myself, bbut I've had some of the same concerns, since I have the same shutter you do.
Paul at Visual Products didn't seem too concerned, and I trust him, but I can't say for sure.
I wonder if the bowtie = smear thing isn't an urban legend.

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#3 Robert Hughes

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Posted 02 June 2005 - 10:17 PM

Apparently Derrick Whitehouse has concerns about smearing and the bowtie shutter, so it's attributable and not quite a urban myth:

http://www.cinematography.net/Pages GB/CP16.HTM

Whether bow tie = smear has not been definitively answered. I've read some say that smear is inevitable with the bowtie design, yet also seen other people's postings saying their camera has no smear. Would it get worse after opening up the gate another 2 mm? Maybe yes, maybe no...
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#4 Carl Durrenberger

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Posted 02 June 2005 - 10:18 PM

The bowtie=smear thing is absolutely NOT urban legend. The smearing occurs in the upper right corner of the frame in highlight regions and can be very noticeable. I bought a CP16/R with the 156-degree bowtie shutter back in 2002 and it smeared really badly.

Just ask the BBC. They returned a large order of CP16/R's to Cinema Products in the 80's because of the shutter smear problem. That prompted a redesign on the camera to the 170-degree "half-moon" shutter, which fixed the problem.

According to Paul Hillman (genius dominus of the CP16 at Visual Products), each CP smears to varying degrees depending on the exact geometry of how the gate and the shutter interact (keep in mind that these were all made by hand, as nearly all motion picture cameras were/are). Some CP's smear greatly (as mine did) and others hardly ever. Paul has a test he has developed to assess the severity of a given camera's smear. It basically measures how completely the shutter blades cover the gate during each exposure event.

Paul also has a fix for shutter smear. He glues on blade extenders to the bowtie to bring the shutter angle down to 144 or 135 degrees so that the shutter covers the gate completely, even if the gate is widened for super-16. I think he includes this prodedure as part of the Visual Products Super-16 conversion; if you have a regular 16 unit, he will charge a couple hundred dollars or so to fix your camera without converting it to super-16.

Paul performed the shutter reduction on my CP16/R and it absolutely fixed the shutter smear problem under all shooting conditions. I highly recommend it. The only downside is that you lose a bit of expsosure with the 135-degree shutter angle and that movement tends to take on a slightly more staccato or strobey quality than with the 156-degree and 170-degree shutters. A worthwhile tradeoff, in my opinion.
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#5 Preston Herrick

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Posted 03 June 2005 - 01:34 PM

I had Paul Hillman convert my CP to S16. It has the bowtie shutter. He has to modify the shutter slightly to make it work as described by Carl. I have since shot with it with very nice results. I've noticed no discernable smearing before the conversion. Everything I've shot with the camera has been telecined. BTW his videotap option (his own design) is top notch.
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#6 Robert Hughes

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Posted 03 June 2005 - 02:13 PM

Did you get yours rebuilt with a PL mount or did you keep the CP-R mount? And is the videotap a permanent mount or removable? Color or b/w?
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#7 Preston Herrick

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Posted 03 June 2005 - 06:47 PM

Did you get yours rebuilt with a PL mount or did you keep the CP-R mount? And is the videotap a permanent mount or removable? Color or b/w?

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I kept the CP mount. An adaptor is available for PL mount lenses. The tap is a permanent mount but it's very low profile - not at all like the original CP tap. Basically a small box where the removeable plate is on top. I was cheap and got the B&W but I believe he offers either.

The conversion also involves machining the gate and having the "fiber optics screen" (ground glass) remarked. No mods are done to rollers and I've had no problems with scratches along the edge.
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