| Author | Message | ||
     Glenn Middleton Rating: N/A |
Robert, Not having an example of this lens, I was just trying to find out if the focus ring had its proper limits of rotation. These three screws, how are they spaced from each other? 120 degs, or are they in a single slot relatively close to each other? To lock the ring on the lens, I would expect them to be at 120 degs and the screws to have 'pan heads' that tightened onto the ring. Your description has me seeing the heads fitting in the slot, thus acting as some kind limit stops. If the screws are clamping screws, one reason that the ring is still slipping could be that the clamping surface has worn and the screws are bottoming in their respective holes. Another thing, you say lens does not focus - this being checked on a camera I suppose - but are you sure that the actual rear group is not moving? If lens has been assembled wrongly at some point, you could get the 'non focus' problem. At moment I cannot get round the fact that focus ring moves over its correct limit. Well not exactly true, I can give an explanation for my Canon FD lenses. If rear group does not move in and out, does it rotate when you turn the focus ring? I may be completely off track but if anti rotation screw/peg or whatever is missing from the helix, it is possible that you will not get in/out movement but only rotational movement of focusing group - sometimes there can be a very small amount of in/out, but this can be hardly noticeable. If the helix has seized it is possible that the anti rotation device has been sheared off by using brute force. Sorry if this seems overly complicated and unhelpful, always easier with a similar beast or diagram infront of you. Glenn. |