Lens mount converstion and Mirror polishing

Philip Kral · February 13, 2017

Someone correct me if there was a more appropriate board to put this under,

I have a Super 16mm converted GSMO with a video tap and a repaired/ upgraded circuit board.

Lately I've been thinking of either upgrading it to a PL mount or at the very least having the reflex mirror polished/ cleaned. However, I seem to be having issues with finding anyone to do either. I realize it's a rare camera and hard to find- for example- spare parts... but I assumed either polishing a mirror or fitting in a mount housing would be generally a straight forward process (Albeit the hard labor with micro measurements obviously). One I could see an issue with, but both?

Anyone have any ideas who may be able to perform this service?

Simon Wyss · February 13, 2017

What’s the matter with the shutter mirror? Have you scratched it?

Gregg MacPherson · February 13, 2017

Philip, where are you located..?

Philip Kral · February 13, 2017

The mirror was like that when I got the camera. Honestly, I usually just ignored it- I can focus all the same. Recently I used a friends Super16mm camera and I must admit, it was nice having a cleaner mirror- especially when using the video assist.

It has some light scratching, but overall I think the mirror is either really filthy or the silvering is wearing down. There's this smudge that when you look through the viewfinder, looks like a streak when you slide your finder across a dirty windshield. I tried applying some cleaner over it, but nothing seems to happen, making me realize it's obviously much more then dirt that's the problem. Now that I think about it, perhaps the work that needs to be done is more then just a polish-but it needs work just the same.

I'm in the NY area, but considering the job(s), I'm willing to send it out.

Dom Jaeger · February 14, 2017

I'm sure you could find someone to convert the mount to PL. Have you asked all the usual suspects, Bernie at Super16inc, Du-All, Les Bosher, Visual Products, Whitehouse AV?

I don't know what the mirror on a CP GSMO is like, but on other cameras they are front surface mirrors with a very, very thin silver reflective layer, you can't just polish out scratches. You might find an optical outfit that could strip and recoat the mirror base, but you'd need to have the mirror removed and when refitted the crucial flange to groundglass distance (as reflected off the mirror surface) would need to be reset and the absolute flatness of the spinning surface checked and possibly adjusted. The reflex mirror setting is one of the trickiest parts of a motion picture camera, definitely not 'a straight forward process'.

Google 'cleaning a front surface mirror' for tips on cleaning, they are very susceptible to scratching. I avoid cleaning mirror/shutters unless it's absolutely necessary. If you've tried cleaning but it still appears foggy, then the reflective layer may be worn as you surmised. When it's spinning you can't see any surface marks, so smudges through the viewfinder of course will be in the viewfinder optics.

Philip Kral · February 14, 2017

Bernie won't touch them anymore because he's worried about the tricky electronics.

Visual products never got back to me, so I should give them a follow up call.

I think they (visual products) said they would contact Whitehouse AV for parts, I should give them a call too just to touch all my bases.

I think i already called Du-All and they said to try visual products.

I got into contact with Les Bosher about the other option: lens mount adapters. They informed me that they can only make Arri-B, M42 and Nikon lens adapters for CP. However, when I try to order them, they never return my messages. I'm assuming they won't answer my PL question either.

On a side note, I already have an M42 adapter. But mine seems to be a macro adapter, I was wondering if someone could cut it down to make it a "normal" lens adapter.

The "smudges" are definitely on the mirror and not the viewfinder.

Jay Young · February 14, 2017

Visual Products quoted me $695 to convert my CP to PL mount, and I understood them to say it was the same for all CP cameras. That seemed to be a straightforward price and job.

I do wish I had a video tap, but I'm not paying more than the camera is worth for the option!