Getting c mount zooms to properly focus

P

pomoville

Well-known member
Anyone got any tips for this? I bought two zooms off of ebay -- a Fuji 14-70mm F2, and a Kowa 17-102mm F2 -- and neither one of them will properly focus wide open. I've tried to shave a bit of metal off both the mount and my adapter, and while the Fuji is getting pretty close, it's still not quite there. I've been trying to think of novel ways to get the back element to poke in through into the camera, but I've come up somewhat short so far.

A couple images of the mounts (first and last are the fuji, the middle is the Kowa):

lense1.jpg


lense3.jpg


lense2.jpg


Anyone have any similar situations that they've worked out? Any help would be appreciated, and I imagine that it would help other people out as well.

P.S. Do the ultra thin adapters make a difference?
 
You're just gonna have to keep shaving on man, and yes having thin adapters with lots of clearance helps. It's the milimeters that maketh the difference. Btw what c mount adapter are you using? Hawkpeng (off ebay) adapters have a lil bit more room than RJ, FYI.
 
Not sure the type, but I bought it from Henry Digital.

I guess I'll buy a thin adapter, then -- I've been shaving the heck out of my current adapter, meanwhile, and the silver lens is getting pretty close. Can't shave too much more off, though. I'd like to figure out a good way to get the bronze screwmount to rest deeper into the lens, so that the rear element will pop through further into the cam. The black one is doing pretty well as a macro lens.
 
with my adapter from memory i have to firstly shave diameter to fit adapter then make sure its 3mm deep or so in depth to mate flush with it.
 
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