ARRIFLEX 2A

John Sprung · January 13, 2009

Two more questions ;)

What´s about the door? Can i change it to a newer one with a Video-Tap? These Body parts looks interchangeable. Also i would use a periscopic viewfinder.

Hmm Flickerfree with HMI and 120°, if i use 50Hz Frequency HMI light... on 25 or 50 f/s there won´t be a problem?? 24, 30, 40, 60f/s for 60Hz ?

(1/75 exposure time = Frequency; 360 degrees x 25 Hz / 120 degrees = 75Hz)

Hmm.

Sometimes i´m unsafe.

Best, Philip!

You should be able to find a II A/B video tap door. But keep your original door. It's convenient to use some times, and the value of a complete antique set is higher.

IIRC, the periscopic finder was introduced with the II-C, along with the full aperture ground glass and the "bulge" door. The A and B doors were flat, and the axis of the finder was parallel to the optical axis of the taking lens. The "C" re-design also angled the finder opical axis outward a little, so I doubt that a "C" door would work. But I've never tried it. If you take your camera to a local rental house, they might let you try a "C" door to learn for sure.

Shutter angle doesn't matter very much for flicker. What you want is that every frame gets the same amount of light. You get two light pulses for every AC power cycle, so in Europe you have 100 light pulses per second, and in the 60 Hz countries, 120 light pulses per second. What you want is a whole number of pulses per frame. So the frame rates that work well in 50 Hz countries are 100/1 = 100, 100/2 = 50, 100/3 = 33.33333, 100/4 = 25, 100/5 = 20, etc. Over here, it's 120/1 = 120, 120/2 = 60, 120/3 = 40, 120/4 = 30, 120/5 = 24, 120/6 = 20, etc.

-- J.S.

Philip Reinhold · January 13, 2009

You should be able to find a II A/B video tap door. But keep your original door. It's convenient to use some times, and the value of a complete antique set is higher.

IIRC, the periscopic finder was introduced with the II-C, along with the full aperture ground glass and the "bulge" door. The A and B doors were flat, and the axis of the finder was parallel to the optical axis of the taking lens. The "C" re-design also angled the finder opical axis outward a little, so I doubt that a "C" door would work. But I've never tried it. If you take your camera to a local rental house, they might let you try a "C" door to learn for sure.

Shutter angle doesn't matter very much for flicker. What you want is that every frame gets the same amount of light. You get two light pulses for every AC power cycle, so in Europe you have 100 light pulses per second, and in the 60 Hz countries, 120 light pulses per second. What you want is a whole number of pulses per frame. So the frame rates that work well in 50 Hz countries are 100/1 = 100, 100/2 = 50, 100/3 = 33.33333, 100/4 = 25, 100/5 = 20, etc. Over here, it's 120/1 = 120, 120/2 = 60, 120/3 = 40, 120/4 = 30, 120/5 = 24, 120/6 = 20, etc.

-- J.S.

Thanks for the values!

If they have a 2c, i think only for decoration, but im sure that i can try the door on my 2a. If it works i will write it.

Best, Philip!

Philip Reinhold · January 16, 2009

Right now i got it! Serial #2312

And i tried it out: the motors are running, (both, the original and the tobin crystal) all lenses are clear (there is a 50mm lens with it), the perforation movement (old button Style) works on the first view. But running the camera with stock in there, looks like the magazin works faster than the perforation movement.

Does anybody know this problem, or the way to resolve it? Pictures below...

thanks!

The arriflex IIa

the movement problem.

1

2

3

- Philip!

John Sprung · January 16, 2009

But running the camera with stock in there, looks like the magazin works faster than the perforation movement.
Does anybody know this problem, or the way to resolve it?

It sounds like the eccentric or a gear might be slipping on its shaft. Or, worst case, there might be a gear with stripped (broken) teeth, which is what I have on #1420.

Take the door, magazine, and motor off. Reach inside and hold the eccentric disc with your left thumb and first finger while you try -- but not very hard -- to turn the inching knob and the mag drive gear with your right hand. If you get slippage, next you have to find where it is. Look at the eccentric disc while you make it slip, and see if the shaft in the center moves. If not, we have to get into taking the left side (gear cover) off. It's very important to inch the mirror shutter out of the bulge when you do that. Take off the inching knob, loosen all the screws a couple turns, and break the castings loose. Then take the screws all the way out and lift the cover in a direction parallel to the plane of the mirror shutter.

If you don't feel it slipping, inch it forward several frames, and you may feel the skipping/resistance that happens due to stripped gear teeth. I hope not, because that's a more difficult and expensive thing. The gears aren't easy to find.

-- J.S.

Philip Reinhold · January 17, 2009

It sounds like the eccentric or a gear might be slipping on its shaft. Or, worst case, there might be a gear with stripped (broken) teeth, which is what I have on #1420. ...

If you don't feel it slipping, inch it forward several frames, and you may feel the skipping/resistance that happens due to stripped gear teeth. I hope not, because that's a more difficult and expensive thing. The gears aren't easy to find.

-- J.S.

It feels like the bigger problem, sometimes its skipping a bit. But ive opened the camera and took a look at all screws, they seem to be okay, all gear looks good. Pictures below...?

Thanks, Philip!

John Sprung · January 20, 2009

I'm sorry, I should have thought of this before: The problem might not be in the camera body. It could be in the magazine. If the takeup side sprocket or the gear on its shaft are slipping, the tension on the takeup core spindle might be able to pull them forward faster than they should go, which would make the lower loop in the body get shorter, as it appears in the pictures.

Since you have the gear chamber open and you feel some resistance, go through it carefully to see if you can find the cause. Turn the gear train from the bottom until you feel some resistance. Then, with a magnifying glass, look carefully at the places where gear teeth are being brought together. There might be some dirt or hardened grease that you can carefully scrape away. You might also try loosening the tachometer and disengaging it, the resistance could be in the tach.

Another thing worth doing now is to check that the shutter and pulldown are properly synchronized.

To the extent that I can see them in the photos, the gears do look good.

-- J.S.

Philip Reinhold · February 22, 2009

A friendly rental in Berlin is checking my camera now! Cinegate Berlin, very nice people!

I´ve just take a look at ebay and find an another Model 1. There is a link with test footage in, the image is very steady.

(Look more like a cam with a Register- pin)

Maybe i´m wrong, but in the pictures below the bargain there is one of devolped footage what looks more like s35?

http://cgi.ebay.de/Arriflex-35mm-1941-42-A...1QQcmdZViewItem

best, Philip!

Edited February 22, 2009 by Philip Reinhold

Hal Smith · February 22, 2009

I'm sorry, I should have thought of this before: The problem might not be in the camera body. It could be in the magazine. If the takeup side sprocket or the gear on its shaft are slipping, the tension on the takeup core spindle might be able to pull them forward faster than they should go, which would make the lower loop in the body get shorter, as it appears in the pictures.

Another possibility: The film speed rate in and out of an Arri II magazine is controlled by the center gear and two sprockets in the mouth of the mag as driven by the gear train in the camera.

Since this is a true Pre-World War II vintage Arri I camera I wonder if the problem isn't that the gear ratio between the camera and the magazine is different than the Postwar Arri II's. Since Arri recreated the camera, not having the original drawings, it's possible the total gear ratio between the driveshaft and magazine drive gear in the camera and the drive gear in the magazine is different by one tooth or so between the two cameras. If this is true, a prewar camera requires prewar magazines.

Anyone have any hands on experience with mixing and matching Pre- and Post-war Arri I and II (and/or Cineflex) cameras and magazines? Is a Cineflex an Arri I or II clone?

John Sprung · February 24, 2009

Is a Cineflex an Arri I or II clone?

It's a clone -- reverse engineered -- from the Arri I. It was made during the war. BTW, Arri didn't call it the Model I at that time, it was called the "Hand Camera". They weren't expecting to make a model II.

-- J.S.