[Groundloop]

I'm hoping someone can help with this.

While shooting the Canada Day fireworks (Canada Day-2008 - a set on Flickr) Tuesday night, I put my 135 f/2.5 S-M-C Takumar on my camera, and when I turned the focus ring, it turned smoothly as usual, then there was a brief rough patch, then it was smooth again until it stopped at the infinity mark. When I looked thru the viewfinder, the fireworks were not in focus. Not even close. Not having the time then to trouble shoot, I switched to my Super Tak 105, and kept shooting. I had some time earlier today to take a look at the 135, and with the focus indicator at the infinity mark, it would actually only focus about 12 feet away. Hmmm. I loosened the screws on the focus ring and played around a bit, and I can get it closer to correct (focus indicator at 5 meters, actually focus distance 7 meters), but it still won't focus to infinity.

Any suggestions? Or is this a job for my friendly neighborhood repair shop?

Thanks.

[jslifoaw]

are you using a flanged adapter? If the lens is not mounting flush with the body mount, it's acting as a very short extension tube, causing you to potentially lose infinity focus.

[little laker]

are you using a flanged adapter? If the lens is not mounting flush with the body mount, it's acting as a very short extension tube, causing you to potentially lose infinity focus.

It worked before, and the other lens appears to work fine for Groundloop, so we can assume that isn't the problem



Groundloop, All that you can do it take it apart to the point where you can properly inspect the focus controls.
And see what's happening.

This link, will give you an idea where to start. Although it doesn't show you everything.
I'd set everything that you disassemble in order, so it isn't that hard to re-assemble

Have fun with it, and good luck.

[Groundloop]

Thanks for the link Stu. I'll have to ponder a bit before opening the lens. I don't have a "clean room" to work in, and my fear is that the best result I could expect is a properly focussing lens that's full of cat hair!

[little laker]

It's summer, even in Toronto

So what I'd do is on a nice day buy a tinfoil oven sheet, and work on it on the deck or some place where you have lots of light.

The most important things are
-no wind
-no dust. Spraying the table your working on with a little water should help int his department.
-just relax and take your time.

It really isn't too hard to work on Pentax Primes