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John Young

CP-16R finally arrived, question about viewing screen

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So finally, I bought a CP-16R #1291R (Actually it's a CP-16R/A but didn't include the sound head).

It's very clean on the inside, and 4 hours with alcohol got the outside clean.

 

 

As my understanding goes, the fiber optic viewing screen can be removed to be cleaned. Since it can be removed, I was wondering if anyone had tried to change it or update it.

 

I really don't need TV Safe markings anymore. The 1.85 markings are nice, but the TV safe really get's in my way!

I would like to keep the 1.85, as it translate well over to 16:9.

 

Another question is if I do as I have planned, and shoot 2x anamorphic, will the TV safe be useful in that instance?

I can't see why it would, as with the anamorphic I'm going to use the entire frame (or hope to).

 

Also, It seems that the Angenieux Zoom that I have (the 10 - 150... 10x15 B) vignettes at the following (just in case anyone wants to know):

 

10mm + focus at end of red line (closer than 5 feet), Severe but outside TV safe.

10mm + focus 8 feet, no vignette.

50mm + focus at end of red line, no vignette.

30mm + focus at 5 feet, no vignette.

Between 12mm - 20mm + focus at 8 feet, very slight vignette.

On this lens, anything past about 35mm will not vignette.

 

Also, this lens states the aperture is 1:2_2.8 - I have no idea what that means. I do know that I would call this lens a T2.3, since that what it is wide open.

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You can remove the viewing screen by loosening the 2 screws that hold the retainer and sliding the retainer up. Using a piece of masking tape you can then hold the bottom of the screen and slide it out. On earlier models there was a spring clip instead of a retainer, which could be unlatched on the right side and swung clockwise out of the way. The screen can be cleaned with alcohol and a cotton swab.

 

I'm not sure if you'll find one without the TV safe markings.

 

The front barrel on Angenieux zooms often stated the maximum geometric aperture (f-stop), while the iris ring was marked in photometric stops (T). So the 10-150 is T2.3 but f2. I don't know why it reads 2 - 2.8 though.

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Usually when a zoom has a range indicated as the maximum aperture, it's because these lenses do not a have constant maximum aperture throughout all focal lengths.

The largest opening (in this case f/2) is for the wide angle focal length and the smaller opening (in this case f/2.8) is for the maximum telephoto focal length.

 

Cheers,

Jean-Louis

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Hi Jean-Louis,

 

I thought that might be the case, but then how do you know when the aperture limitation kicks in?

 

Does the maximum aperture slowly move from f2 to f2.8 through the focal range, or does it only begin as you approach telephoto?

 

I imagine it's a condition of the lens having a long (15 x) zoom range, so maybe only the very long end is affected?

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Hi Jean-Louis,

 

I thought that might be the case, but then how do you know when the aperture limitation kicks in?

 

Does the maximum aperture slowly move from f2 to f2.8 through the focal range, or does it only begin as you approach telephoto?

 

I imagine it's a condition of the lens having a long (15 x) zoom range, so maybe only the very long end is affected?

 

 

 

 

Hi Don,

 

I was curious about this myself so I did a little experiment; measuring the exposure at the film plane with the lens at maximum aperture.

 

From 10mm to 20mm: no discernable variation from the max.

Between 20mm and 25mm exposure starts to decrease.

At 50mm, 1/3 stop is lost.

At 100mm, 2/3 stop is lost.

At 150mm, one full stop is lost.

 

So it's pretty much a gradual decrease.

 

Note that this only applies when the aperture is set to the maximum.

 

At a middle aperture like f/5.6 or f/8, there is no exposure variation when zooming.

 

This got me curious about the 12-120mm so I tested one too at maximum aperture.

 

Pretty constant throughout, but there is a slight dip at the telephoto end starting gradually at between 70mm and 90mm and reaching 1/4 stop at 120mm.

 

Cheers,

Jean-Louis

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Didn't want to start a new thread...

 

Can anyone help me with why my CP will not run?

 

I have a 24v battery with XLR adapter on the camera.

I get nothing from either switch (run/stop or front thumb button).

I even tried to power it with the charger for the battery pack (outputs 20v) and nothing.

 

Well, after playing with it I decided to call Paul over at Visual Products and send it on down.

He couldn't figure out anything over the phone, so it must be something internal.

Since I need it for a shoot at the end of the month, better let him look at it now.

 

Anyone have any thoughts otherwise? Is there some secret to getting these to run?

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...Can anyone help me with why my CP will not run?

 

Well on the face of it, and with the information you've provided, I might suggest a flat battery!

 

To charge up a 24 volt battery you need to have a charger with an output higher than 24 volts.

If your charger will only output 20 volts, then it won't be recharging the battery. :unsure:

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I totally agree the battery is flat, but I powered it directly from AC/mains power. I thought that 20v DC from the converter would output enough power, but nothing happened.

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I totally agree the battery is flat, but I powered it directly from AC/mains power. I thought that 20v DC from the converter would output enough power, but nothing happened.

 

I don't know the camera, but the current required to recharge a battery over a long period of time could potentially be much less than that needed to run the camera.

 

My NPR is rated for the 4Ah battery to run the camera for about 1hr 40minutes. That means it's normally drawing about 2.4 amps whilst running. It's possible your mains power supply is unable to supply sufficient current for the camera to run?

 

 

Alternatively, the camera might have an undervoltage cutout circuit which prevents it running if the supply voltage is too low? 20V would be the sort of voltage I'd expect a flat 24V battery to measure out at.

 

Do you have access to an alternative 24V battery that is charged up?

 

How about two 12V batteries wired in series just to try it out?

 

It would be frustrating to send the camera off to be repaired only to find there's nothing wrong with it other than a flat battery and a duff charger!

Edited by Ian Cooper

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So the camera is on its way back to me.

Paul said the clutch was shot, and put a new one in. He also removed the mercury battery, and oiled it.

Since the camera was shipped with the lens ON the camera, Paul checked the rear focus and alignment.

The battery finally came up to stable voltage after days and days on charge.

 

Apparently the camera runs perfect now! I'm excited.

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Another question is if I do as I have planned, and shoot 2x anamorphic, will the TV safe be useful in that instance?

I can't see why it would, as with the anamorphic I'm going to use the entire frame (or hope to).

 

The sides of the TV safe area will give you the side lines for 2.35:1/2.4:1.

 

 

Also, It seems that the Angenieux Zoom that I have (the 10 - 150... 10x15 B) vignettes at the following (just in case anyone wants to know):

 

10mm + focus at end of red line (closer than 5 feet), Severe but outside TV safe.

10mm + focus 8 feet, no vignette.

50mm + focus at end of red line, no vignette.

30mm + focus at 5 feet, no vignette.

Between 12mm - 20mm + focus at 8 feet, very slight vignette.

On this lens, anything past about 35mm will not vignette.

 

Also, this lens states the aperture is 1:2_2.8 - I have no idea what that means. I do know that I would call this lens a T2.3, since that what it is wide open.

 

Apparently Ang. orignally developed a 12-150mm zoom for a NYC camera house, then realized that if they allowed vignetting at close focus on the wide end, the lens could be adjusted for a 10mm wide end. Some of the 12-150s did get out on the market.

 

There should be should be interconnecting locks between the f-stops and zoom control, so that if you're wide open, the zoom will stop where the f-stop changes. Stop down to f/2.8 & you zoom all the way through.

The 9.5-54 is similar.

It seems some cameramen had this mechanism disabled or,perhaps, it breaks rather easily.

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