 Posted: Sat Apr 20, 2013 10:43 am Post subject: Re: Konica 50mm f1.4 AE |
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konicamera wrote:
| Layer-cake wrote: |
 I decided to clean the focus ring on my beautiful Konica lens and seem to have gotten myself I to a bit of a situation.... the lens used to focus at infinity slightly before the infinity mark and since the cleaning it seems to focus perfectly at infinity. its still sharp as hell but i'm paranoid that I'm not getting proper infinity focus on it anymore!!
why would the cleaning affect the infinity focus point, I did a good job with positioning of the helixes when re assembling the lens so its not that, if it were it would be rather blatant as the markings wouldn't match up correctly even if it was out by one notch.
its my favourite lens out of my collection and I wanted it to be a bit easier to use as I found the amount of dampening a bit on the heavy side. On a positive note the focus is smooth as butter now, not as good as a super takumar but hugely improved. |
Just a couple of ideas off the top of my head:
If I remember correctly, the focusing ring and the outer helicoid are two separate parts held together by three screws that can be accessed by screwing out the front ring. These screws usually have a dab of laquer on them to prevent them from loosening, but I've seen some become loose. Once this happens, the focusing moves in relation to the helicoid. If you can sense a slight back and forth wobble on the focusing ring, that's probably where the problem is.
If there is no wobble, perhaps the old grease had hardened in places to such a degree that the focusing ring never came up flat against the focus stop in the first place, which is probably why the focusing ring used to stop slightly before the infinity mark. If that's the case, your lens should be OK now and was off before.
A rudimentary method for checking focus is to tape some opaque scotch tape across the film gate; place the camera with its open back on a tripod'; point it far away and set the shutter speed to 'B' (you'll need a shutter release cable). Once this is done inspect the image on your scotch tape "focusing screen" with a magnifying glass. If you have a magnifier viewfinder attachment, it makes the entire exercise far simpler. as you can check your focus on the camera's focusing screen. |
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