| Author |
Message |
    
Lensfan
Tinkerer
Username: Lensfan
Post Number: 3
Registered: 04-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 06, 2008 - 05:28 am: | 
|
Hi,
I have a very unusual movie camera lens used for filming 35mm cinemascope motion picture films that I would like to repair.
The lens is an anamorphic lens that compresses the image in the horizontal direction by a factor of two! It is called an Ultrascope lens and was used on Arriflex 35mm cameras, dating from the 60-70s.
The lens has two significant problems. One is that I cannot get the lens to focus when on the matching camera. The other issue is that the focus ring is stiff in some areas.
Can someone help with some generic lens dismantling and repairing tips that I might apply to this unusual lens?
Thanks From,
H. |
Glenn
Tinkerer
Username: Glenn
Post Number: 313
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 06, 2008 - 11:03 am: |
|
I would suggest that your major problem is the inability to focus, with the lens mounted on the camera. Even will the lens helix completely seized, you will still be able to get a defined focus - at some distance from the film plane.
This problem could be due to a couple of reasons; there is part of the mounting system missing, or the lens has been dismantled before and reassembled wrongly. You do not state how the focus stiffens up. If the stiffness is at either end of the focus range, then old lube could be the reason. If the focus 'grabs' through out the focus range; then my gut feeling would be that the lens has been reassembled wrongly, or otherwise damaged.
If the lens has been got at, you have a problem in stripping it without the repair manual. You have no reference to what the correct assembly sequence is, even when you make copious notes, it can be very frustrating working through the many permutations of assembly - until you stumble on the correct sequence.
On lenses that are not mechanically complex - no auto diaphram etc, I usually start by removing the mount, then try and work out how the optical cell/cells are held in the actual helix assembly. Sometimes all that needs unscrewing is a locking ring - which is removed from the rear of the barrel.
I would suggest you need advice from someone with intimate knowledge of this lens. I certainly would not start taking it apart, until the reason for the lack of ability to focus has been found. |
|
