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02-22-2013, 11:25 PM   #16
Just1MoreDave's Avatar

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Trial and error should work. The two times I've done it, the large threads appeared to have three starting points. I think this lens is typical construction. The focus ring is attached to a ring inside with really fine-pitch outer threads that are a few millimeters deep, and coarse steeply pitched threads inside. Then the lens tube has matching coarse threads. The lens is at its shortest overall when it's at infinity focus, so at that point, the ring with the fine-pitched threads is almost fully tightened to the body of the lens, with a little slack for adjustment. I guess at about a quarter turn of slack. Then you can unscrew it again for the distance between infinity and the minimum focus distance on the distance scale of the lens, about 200 degrees on my EL version. Now that ring is approximately in the position it would be if you focused to the minimum distance. Obviously a few of the coarse threads are engaged here or the front of the lens would be almost falling off at minimum distance. I guess again at how much more to unscrew the ring, something like a half turn.

Now you can try to engage the coarse threads, noting each entry point so you don't have to repeat the trials too many times. Turn the ring to bring the lens tube into the lens and see if all the parts line up properly. If not, reset the ring, rotate the lens tube 120 degrees and try again.

02-23-2013, 02:47 AM   #17
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QuoteOriginally posted by LayerCake Quote
evening blokes, came across this and everything seemed simple enough as I had the same problem with the aperture blades on my tokina 28mm (got that fixed!!! so many thanks for the thread but went a bit too far with disassembly and removed the focus ring and didn't mark off the point it came off the thread or how far to screw it back in..... tried a couple times but not really getting anywhere!! not sure if you went through this procedure with disassembly but if anyone has any idea of the correct positioning of the focus ring for reasembley it would be much appreciated!!!

I never had any problem with that, so i left it intact! But PLEASE, take photos you aswell and put up here, so that people in the future can find this thread and solve their problems properly aswell!
02-23-2013, 08:43 AM   #18
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Hey thanks for the replay, going to attempt it tonight when I get back from work!!

If I succeed I'll gladly put up some photos if not I'll be back begging for photos of the lens fully zoomed in and fully zoomed out just to see to proper spacing!!! It's a nice simple lens, tried to take my pentacon 135mm F2.8 Zebra apart as it has some haze on the inside of the front lens but literally stopped dead after removing the back piece and realised I was about to bite into something that I would probably completely destroy in the process!!

Again thanks for the insight.

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