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12-08-2011, 07:19 AM   #1
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Focus problem A 35-70 zoom

Hello, I have completed cleaning a new eBay purchase 35-70 A zoom, at the 70 end I can achieve infinity focus, but at the 35 end anything further than 3 meters I cannot bring into focus, has anyone else had this issue? The focus stop lug feels like it should be 5mm further away so there is more travel. The brass ring around the front element has 12 holes and 3 screws, maybe this calibrates the focus throw? It doesn't have a 3 screw and washer adjustment like primes I have seen. I hope this makes sense, any help would be greatly appreciated.

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12-08-2011, 02:49 PM   #2
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Sounds like it might be a mechanical problem...do you have pics of the front?

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12-08-2011, 03:03 PM   #3
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I have this lens but it was partly disassembled at the mount end when I got it. So I'm not 100% sure how the adjustment is supposed to work. Someone may come along with better advice, but here's my guess:

If I remove the screws and brass ring, I think the focus ring becomes disconnected from the lens. I might try zooming to 35mm, focusing to the infinity mark, loosening the three screws, then see if you can turn the focus ring a bit away from the infinity mark without actually focusing the lens. (It has to be a very small adjustment, because the throw is really short on this lens and it works at 70mm.) If that works, you should be able to tighten the screws and slap the trim ring back on.
12-08-2011, 03:48 PM   #4
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QuoteOriginally posted by Just1MoreDave Quote
I have this lens but it was partly disassembled at the mount end when I got it. So I'm not 100% sure how the adjustment is supposed to work. Someone may come along with better advice, but here's my guess:

If I remove the screws and brass ring, I think the focus ring becomes disconnected from the lens. I might try zooming to 35mm, focusing to the infinity mark, loosening the three screws, then see if you can turn the focus ring a bit away from the infinity mark without actually focusing the lens. (It has to be a very small adjustment, because the throw is really short on this lens and it works at 70mm.) If that works, you should be able to tighten the screws and slap the trim ring back on.
Thank you for the suggestion, I'll have a look tonight, I suspect that I have not paid enough attention to the finer adjustments when reassembling, this lens was sandy and had fungus so there was no option but to clean it thoroughly. After successfully negotiating the detent ball and A lug and spring
reassembly, how hard can this part be eh?

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