Canon FD Zoom lens question.

[anandi]

Hello,
Once again not 100% RF related, but I got a Canon FD GAS attack because of this forum (in my defence).

So off of *bay I picked up a 35-70 Canon FD (f3.5-4.5) zoom lens, so not super great, but most FD lenses are at least okay. Got it in the mail today and mounted on my A-1 and this is what I find:

1. When focussed to infinity, I can never get the split prism to line up, the matte focus screen is also a little of focus - WTF?

2. There is a little slop in the front face of the lens, back and forth.

Does anyone have an explanation for this? Did I get ripped off? Will the slight mis-focus matter with smaller aperatures as we approach hyperfocal distances?

Thanks.
-A

 

[CleverName]

I have the same lens although I've never shot with it, it came on an A-1 I bought at the flea market. Mine has a little bit of slop also, it may be a "design feature". It seems to focus OK.
I'm just guessing, but I would say that if it's out of focus, it will out of focus no matter what aperture you use. Did you try backing off infinity just a little? It's possible the focus ring got twisted too far, or the lens got dropped or something and is trying to focus beyond infinity. (As if there's anything beyond infinity 😀 )

 

[StuartR]

I have only used one zoom in FD (the 80-200 f/4L), but that does not sound right at all. If it is out of focus in the viewfinder, it almost certainly means it will be out of focus on the film as well. Have you done any sort of critical tests with it? In any case, zooms were kind of in their infancy during the heyday of the FD system, so I don't think they are really the best choice unless you shell out the dough for the L series zooms (even then I think you would do much better by the primes). Either way, I think the best thing to do would be to focus critically, wide open and close up on a ruler or something, and see if the point of focus is where it should be. That will give you your answer. If it does not make a difference, then you are set.

 

[anandi]

Thanks for the advice, I'm going to shoot a roll of film with it and see what comes of it at a wide range of zooms and distances to focus on. I've got a 50mm, 28mm and a 70-210 lens and was looking for something more versatile in the 'normal' range. I like the 35mm field of view, but have at least 3 other RF-type cameras with it fixed & built it (Oly XA, Minox 35GL and Yashica T4). I suspect the 35-70 zoom lens gives up a fair bit of image quality as the price for versatility.