Andre Goforth wrote:
> I noticed with one lens(the 300mm
> f4.5) that infinity focus on the barrel is too far, i.e. out of focus.
Long tele lense need this sometimes to compensate the temerature related
change in lenght of the lens barrel.
> Now,
> I have learned from this august mailing list that this is not uncommon with
> long telephotos. But when I tried the 85 I was surprised!
>
> I couldn't turn the focusing ring far enough to get sharp(in focus) focus
> at infinity. I was using a screen with a split screen and could see that
> the image was not comletely lined up. And the image was ever so slightly
> fuzzy.
>
> Yoew. I have rarely if ever used this lens at infinity so it has not been a
> problem. Since it is one of my favorites, if not favorite, I will try to
> get a camera shop to adjust the travel of the lens so that the focus ring
> will travel a little farther out so I can get "exact" focus at infinity.
> Note that the temperature was nominal, around 70 F.
This was one reason for my post "terrestial vs. astronomical infinity".
But first did you checked, that you camera mirror is in alignment? A
misalign mirror might cause the same problem, to check, you could try
out if you have infity problems with your other lenses too.
> Has anybody had similar problems and is there a way to do the adjustment
> one self?
I personaly not, adjustment is normaly not dificult with a
non-floating-element lenses but a floating element (or zoom) lens has
more than one group to adjust (the floating elements). Tempering the
focus adjustment at this lenses may degrade optical performance severly.
I would recommend to give it to an qualified (equipment!) Olympus
service.
Richard
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