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12-09-2011, 03:28 AM   #1
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Pentax-F 50mm f1.7 - Help

I just bought an F 50mm f1.7 which is very good but unfortunately has a pronounced front focus at f1.7 that is not completely corrected neither with -10. I need -1 or -2 more. This is not distinguishable above f2.5 but I want to use this lens from f1.7. For that I need (if is possible) to correct the focus in lens.
I found this:
Can this procedure help me to correct the front focus ?
I don't want to try myself to see if ... or not. I need an opinion from someone that had did this before and know for sure that will work.


12-09-2011, 03:38 AM   #2
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The advice from Just1MoreDave seems to be pretty straight forward and I'm confident to say it will help you to sort out your problem.
Haven't tried it myself (never had to) but it should work....
12-09-2011, 06:03 AM   #3
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Sounds straightforward and simple. Make sure to take pictures as you go, or mark your items, if you're worried you'll not be able to reassemble everything (should not be a problem with this simple procedure).
12-11-2011, 05:31 AM   #4
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Original Poster
Hi again,

I just finish the focus adjustment on the lens. It was an adventure.
It is now perfect lens, eh, almost perfect because I cannot bring in camera focus adjustment to 0 but to -7. Now it is sharp from 1.7 for close object and for distant one (infinity focus).
I used JIS screwdrivers and I needed only PH00 and PH000.
At first I made a mistake: when I unscrewed the screws from the barrel I pressed the shooter button and the focus has been completely turned upside down. It took me some time to bring it to the correct position but I lost infinity focus. After I moved the focus ring back step by step It become better, a lot better then before. I leave it at -7 because it focused perfect and was difficult to bring it as it is now. I don't mind that is -7 adjusted in camera while the focus is spot on from f1.7.

Thanks you all


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