Dyaliscope Junior 16 - Focusing is stiff, need some insight

[John Palmer]

Hello! I bough this Dylaiscope Junior 16 anamorphic projector lens from ebay last week for $51, I was very surprised No one ever out bid me. Optically it is in pretty good shape, some minor cosmetic scratches on the body. The main problem I have with it is the focus ring is fairly difficult to turn. I basically need to take it off the mount to set focus everytime because Im afraid I will put unneccesary stress on the lens and mount attached to the camera.

 

I was just wondering if anyone has any experince or knowledge about lubricating lenses. I already know it is generally not a good idea for a non profession to take apart an anamorphic lens since all the elements need to stay perfectly alligned, but I was wondering if anyone knows the function of the 3 screws towards the back of the lens seen in the picture. I can sorta see a bar inside the lens that they seem to be holding. I have taken apart old Canon fd mount lenses before and reassembled with no issue but Im sure this is a bit more difficult.

 

What would happen if I were to loosen those screws?

It seems to me that this lens has probably been sitting somewhere for a very long time and the original lubricant has become less oily or something. I removed the face plate of the lens with all the writing on it and removed some of the grease and found it was a greenish shade, which I read from other forums is a type of grease known for sticking over time, not sure if it is the same grease used throughout the lens though. From what Ive read Dyaliscope lenses are of pretty good quality but havent been able to really find much about them.

 

Any advice or ideas would be appreciated.

[JohnBarlow]

Those screws hold the rear cell at the correct distance and alignment.

[Hans Punk]

 

What would happen if I were to loosen those screws?

 

 

A world of pain.

 

If you are unsure, I'd say maybe leave it alone...resell it with a clear description of the focus stiffness for a buyer to allow an informed choice on repairing it or not.

 

If this does not interest you, and you fancy attempting a repair yourself -I'd say the best shot to try first is to carefully go in from the front, using a proper tool (spanner wrench to unscrew front retainer ring).This will allow removal of the front optic and allow access to the innards. By unwinding the helicoid you may be able to get access to the movement and thin the old grease with a TINY amount of lighter fluid and swab away some of the old grease with Q-tip/ cotton bud. Then some fresh helicoid grease added. The front optic will have to be orientated back again once you are done, which if you have not done before can be very time consuming and risky - as the edges of the optic will chip very easily.

 

Basically I would not recommend trying anything if you are unsure, it sounds like a full disassembly/ clean and re-lube would be needed to sort out the issue properly, by someone who knows their onions.

[JohnBarlow]

Beware, the front optic is probably glued in with optical cement.

[John Palmer]

Thanks for the advice fellas. I sorta figured those screws would not help me. Even though I only spent 51 bucks for it and since it still turns, just not as smooth as id like, I am probably going to leave it alone until I can invest in something better. Ive been shooting some stuff with it and it hasnt been slowing things down too much anyway.

 

There is an older gentleman in my town who used to make lenses in the UK and owns a camera rental business who might could help me out

 

 

Beware, the front optic is probably glued in with optical cement.

just for future reference, What would it be glued to? An inner barrel or something?

[JohnBarlow]

Construction of the inner tube goes like this:

 

The inside of the tube and the edge of the front optic is wetted with glue. The front optic is then inserted into the tube, followed by the front retaining ring which is screwed in.

 

The tube is stood vertically until dry/cured with the retaining ring acting like a shelf.

 

This is why when you see scopes with tool marks on the front retaining ring you know the skill level of the last tinkerer ;)

 

 

This scope is a very nice optic with pink flares. Yes pink, just like the pink floyd from lightning and plasma balls

[John Palmer]

cool, gotcha. thanks dude.

 

Yea I have noticed that. It it because of the coating?

Also, this is a 2x lens right?

[JohnBarlow]

Sure the coating plays its part, 

 

The scope is 2x when focused at INF