Adjusting infinity focus tokina at-x 80-200 2.8 FD?

[kingbuzzie]

After being frustrated with the pickings on fleabay for a tokina at-x pro 80-200 zoom in fd mount, I paid way too much for one from Japan. It's in nice shape (it's not "mint" as the seller described (some brassing). Much to my dismay it focuses slightly past infinity. I checked on two canon bodies to to make sure. The seller is offering to take it back, but we're having a bit of disagreement over them paying the return shipping (they didn't offer a discount on the lens, which means I assume they are going to try to sell it full price again to someone else). I wish I could just keep the lens, but for what I paid I want it to be dead on and I don't want to monkey around with it if I don't know what I'm doing and lose my $$.

 

[shutterfinger]

Does it focus at close distance as marked/stated at all focal lengths?
Many lens focus past infinity,depends on the manufacturer. Infinity should be center of the infinity mark.
When the description is in error then the seller should pay the return shipping.

 

[kingbuzzie]

At all distances when it hits the infinity stop it is slightly past infinity. It could be a easy fix, but for $200 I don't want to risk it. I've fixed a handful of prime lenses and a few zooms, but they are always different.

 

[Patrick Robert James]

Some lenses are designed that way since they will expand in the heat. Any huge telephoto will focus past infinity.

 

[kingbuzzie]

Some lenses are designed that way since they will expand in the heat. Any huge telephoto will focus past infinity.

So are you saying it's supposed to focus past infinity at the infinity stop or it's supposed to pass the stop? I've never had another zoom that is past infinity at the marker.

 

[Patrick Robert James]

So are you saying it's supposed to focus past infinity at the infinity stop or it's supposed to pass the stop? I've never had another zoom that is past infinity at the marker.

All i can tell you is that long lenses are designed to go past infinity because of thermal expansion. The issue is probably why Canon started painting their huge telephotos white years ago. How that relates to your lens I don't know, but it is possible that it was designed that way.

A lot of times if zoom lenses are mal-adjusted they will go past infinity at one end and won't make it to infinity at the other. If your lens is off the same amount at both ends then it was probably designed that way. Focus on the moon, then see where the marks are. If you are at infinity, then you are probably good. If it focuses correctly at infinity and the stop is past that then it was probably designed that way. Worry less about the stop and more about the accurate focus.

I've never had your lens so i can't tell you if it is normal or not, but maybe this info will help you.

 

[kingbuzzie]

The seller and I have worked out a resolution. I will keep the lens, as it is fairly nice (but not the "mint" they stated).

 

[John Koehrer]

Yeah, what Patrick said; quite a few long lenses; prime and zoom were designed with that expansion in mind.