FD lens won't mount on Letus?

T

Toenis

Well-known member
What would possibly cause that a 50mm f1.4 newest series FD lens will not mount on Letus any more after mounting it on a FD photocamera?
As I've sold my Letus I can not find a first hand solution how to mount that lens on the adaptor any more.
The lens was mounted on a FD camera before and mounted just fine. Also the rear lens cap mounts fine and other lenses mount fine on the adaptor.

Could it be that when mounting the lens on a camera tricks it so it will not mount on the adaptor any more. I've had similar experiences before but I don't know how to solve this problem without mounting it back ta a FD photocamera.

Let me know,
T
 
I had to modify my mount slightly to make one of my lenses fit. Study the cap and you'll probably see a little notch that the FD mount on the letus doesn't have. Take a small file and make a notch and your problems are over. Both the older and the new fd mounts have this problem. I'm not sure why they didn't include a notch.
 
1230915269.jpg
 
Didn't work.
I must mount that lens again to the A1 camera body to return it to the working state I assume.

T
 
When you mounted it to the A-1, a totally automatic-exposure camera, did you turn the aperture ring to the "A" position like you're supposed to? If so, it will no longer mount to most 35mm adapters because of the little signalling pin that pokes out of the back of the mount and into a hole in the mount on the still camera. First push the button next to the "A" and spin the aperture ring down to the numbers, and it should be able to mount up again. Obviously you want it out of "A" position anyway when using it on an adapter, it's just that you have to get it out of that position before even mounting it.

Duncan
 
Hmm thats odd. It worked for me. I had a canon fd zoom and another off brand that wouldn't work til I did this. Are you sure you modified in the correct spot. As long as its exactly like the back cap it should work.
 
That notch you show is in the place where the "A" pin juts out... so having that notch will indeed allow a lens locked into "A" to mount up, but since you can't use the lens in the "A" position with a DOF adapter anyway, there's not much point. It just allows you to mount the lens first and then spin the aperture ring out of "A".

In case it isn't clear from that picture, that is the mounting flange to the LEFT of the lens opening, when looking at it from the front. So the notch would be at about the 8:30 position. (If you're really good, and used your A-1 camera flange as a template, you could actually just drill a small hole there, which would look a lot cleaner.)

Duncan
 
Nice to know what the notch is for anyway. Mine wouldn't mount even out of the A position. I dunno. Anyway, it seems like its useful to have a notch especially if you don't have an A-1 and need to get your lens out of Auto.
 
But what I'm saying is that you don't need the lens mounted on the adapter to spin the aperture ring in and out of the A position. Just holding it in your hand it will do that fine. At least every FD lens I've ever handled, in both the older breechlock and newer bayonet style FD mounts (and that's a lot of them!) If it doesn't, then mounting it on a rear dust cap should accomplish the same thing. The dust caps all come with a hole or slot in that position.

Duncan
 
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