T90 and 135mm f/2 Infinity focus

Hello to the list. I think I've read about this in passing somewhere, but I can't find it again. Now that I have a T90 for the first time, it's of a bit more significance. I mounted my 135/2 yesterday for a portrait of a bell tower, and it won't quite reach infinity focus. No problems with my A-1, and none with other lenses. I seem to remember there was no solution, something about the design of that lens. Wish it would focus a little past infinity like some of the others! Ideas? Thanks!

Seems something is wrong with your T90, or the lens. Check if the

focusing screen is not loose. My T90 and 135/2 does indeed focus to

infinity.

 

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Ketil

Either the screen is out of position (most likely), the mirror is

misaligned or the mount is loose or sprung. You should be able to

check the 1st one by lightly pressing the screen into place. If it's

up as far as it can go then it's time for a trip to the shop.

 

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I'd rule out the lens because it works fine on the A-1. If you still

feel it's the problem, the lens can be adjusted but it's a job for

someone with the expertise.

 

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Cheers,

I had the same problem with a 135 f2 I picked up in Canada. It would

not focus to infinity. I did not try it with any other body, but the

dealer had it repaired. The technician said there was no evidence of

damage or previsou adjustment, so it was like that from the beginning.

 

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May be something that is right on the edge that has a problem with

T90s.

 

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Have it adjusted and enjoy it.

No trouble here. 135/2 on T90 goes exactly up to infinity and

stops. (Although I won't swear to it until something in the universe

gets infinitely far away and light begins to move infinitely

fast. . .)

Thanks for all your responses. Upon further investigation, I believe

I had two factors causing this. The three mount screws that secure

the stainless "bayonet" ring in the mount were *ever* so slightly

loose. Just enough to allow the lens to "droop" a bit under its own

weight. Couple that with a warm temperature and it wouldn't quite

align the split image at infinity. Tightened the mount last night,

with the ring pressed securely to its maximum depth, and tried it

again, with the lens cooler. It focused just a hair's breadth past

infinity. New we'll see what it does in the summer. . . .