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CP16R Test


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#1 James Clement Cook

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Posted 16 August 2011 - 04:04 PM

Hello-

Has anyone designed a really great and thorough test (registration, more) when buying a new camera?

I have this great CP16 in excellent condition and want to shoot some 250D this week.

I hope ultimately to convert this camera to Ultra 16- I just love the idea of it and the workflow with the digital intermediary.

Thanks,

James
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#2 Dom Jaeger

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Posted 16 August 2011 - 11:25 PM

Hi James,

there's no single test, but here are a few things you can do to check the important stuff:

Load up the camera with some dummy stock and with the camera and mag doors open check that everything is running smoothly. A can of expired film is good for this. It's also a good way to get familiar with loading and lacing (in particular the lower loop needs to be correctly set). Check that the doors all seal well, and that the mags and lens attach firmly.

Remove the film and check it carefully for any scratching. Don't worry about occasional random scratches, look for continuous or repetitive marks. Light scratching outside the image area or on the backing you can probably live with until you send the camera to a tech for the Ultra conversion.

Adjust the eyepiece diopter so the ground glass texture is visible, set the zoom to the long end at maximum aperture and focus on a subject 6 feet away. Check that the lens scale matches the distance. Zoom to the wide end and check that the subject remains in focus. Try the same thing focusing on a very distant object (effectively infinity on the lens scale). A discrepancy could be due to either the lens or the ground glass depth, if you have another lens it can be helpful to compare them.

Shoot a registration (or steady) test. I described the procedure in this thread:
http://www.cinematog...showtopic=52742
Remember to close off the viewfinder eyepiece if you're not looking through it when filming (a good idea during a reg test in case you move the camera with your eye pressure. The camera should be very firmly supported.

At the same time you could check the ground glass framing by marking the framelines visible through the viewfinder on to the test chart, which will show you where the framelines are relative to the camera gate aperture when you view the test.

Shoot a focus test. Easiest thing is probably a sheet of newsprint taped to a tilted board. Light it so you are using the the lens at its widest f-stop, where back focus/flange depth is most critical. Focus on a circled word in the middle, start at the long end and work to the wide end. Again, a discrepancy could be the lens or the camera flange depth.

Without a strobe timing gun, you could check the camera speed by either timing how much footage runs through in a certain time period, or filming a clock that displays seconds. Obviously the longer you go the more accurate your measurement will be. The out-of-sync warning light on the door side (and the 'S' displayed in the viewfinder) should tell you if the camera is not running to speed though.

Listening to the camera during film tests will give you an idea of how noisy it is, whether sound work is possible, or when you might need a sound barney.

Most critical are the scratch test, registration test and focus checks. Other potential issues like light leaks or focus breathing in the gate will show up in the filmed tests. To properly check focus issues, the lens collimation and camera flange depth and ground glass depth need to be checked by a tech with a collimator.

Good luck with it!
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#3 James Clement Cook

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Posted 24 August 2011 - 04:28 PM

Dear Dom Jaeger,

thank you very much this is excellent! I will let you know how it comes out

James

Hi James,

there's no single test, but here are a few things you can do to check the important stuff:

Load up the camera with some dummy stock and with the camera and mag doors open check that everything is running smoothly. A can of expired film is good for this. It's also a good way to get familiar with loading and lacing (in particular the lower loop needs to be correctly set). Check that the doors all seal well, and that the mags and lens attach firmly.

Remove the film and check it carefully for any scratching. Don't worry about occasional random scratches, look for continuous or repetitive marks. Light scratching outside the image area or on the backing you can probably live with until you send the camera to a tech for the Ultra conversion.

Adjust the eyepiece diopter so the ground glass texture is visible, set the zoom to the long end at maximum aperture and focus on a subject 6 feet away. Check that the lens scale matches the distance. Zoom to the wide end and check that the subject remains in focus. Try the same thing focusing on a very distant object (effectively infinity on the lens scale). A discrepancy could be due to either the lens or the ground glass depth, if you have another lens it can be helpful to compare them.

Shoot a registration (or steady) test. I described the procedure in this thread:
http://www.cinematog...showtopic=52742
Remember to close off the viewfinder eyepiece if you're not looking through it when filming (a good idea during a reg test in case you move the camera with your eye pressure. The camera should be very firmly supported.

At the same time you could check the ground glass framing by marking the framelines visible through the viewfinder on to the test chart, which will show you where the framelines are relative to the camera gate aperture when you view the test.

Shoot a focus test. Easiest thing is probably a sheet of newsprint taped to a tilted board. Light it so you are using the the lens at its widest f-stop, where back focus/flange depth is most critical. Focus on a circled word in the middle, start at the long end and work to the wide end. Again, a discrepancy could be the lens or the camera flange depth.

Without a strobe timing gun, you could check the camera speed by either timing how much footage runs through in a certain time period, or filming a clock that displays seconds. Obviously the longer you go the more accurate your measurement will be. The out-of-sync warning light on the door side (and the 'S' displayed in the viewfinder) should tell you if the camera is not running to speed though.

Listening to the camera during film tests will give you an idea of how noisy it is, whether sound work is possible, or when you might need a sound barney.

Most critical are the scratch test, registration test and focus checks. Other potential issues like light leaks or focus breathing in the gate will show up in the filmed tests. To properly check focus issues, the lens collimation and camera flange depth and ground glass depth need to be checked by a tech with a collimator.

Good luck with it!


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Metropolis Post

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FJS International, LLC

Abel Cine

Willys Widgets

Visual Products

Gamma Ray Digital Inc

rebotnix Technologies

Aerial Filmworks

Ritter Battery

Paralinx LLC

The Slider

Broadcast Solutions Inc

CineLab

Media Blackout - Custom Cables and AKS

Wooden Camera

Glidecam

Tai Audio

Rig Wheels Passport