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03-06-2012, 11:46 AM   #16
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Borno - I guess that is why I am trying to resolve this without sending it in; you never know who ends up with it where you send it nor are you really sure they know what they are doing with what you sent them. The lens appears almost 100% pristine so it should be within the build specifications and whatever variances that exist in that process - it appears from what I am hearing the allowable variances are skewed to backfocus. How I received it it was packed very well but the lens was also very cold, I mean real cold and temperature can have an effect on variances opening them up when cold compared to a warm temperature where I live which would tighten variances ever so slightly.

Kind of like Murphy's law - you might have got hit with it; the next person is fine - who knows where I end up in the mix so I am trying not to go there.

See how it goes; I will post results and process over a range of lenses that I have that are AF as I go along as I might as well know where all of them hit with AF..

03-06-2012, 01:02 PM   #17
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The FA* 300 2.8 I use to own was -1 on my k7, 0 on one k5, and +5 on the other k5. The k7 wasn't even the same for the three focus points horizontally in the center. But that body was full of little quirks, what you get for buying a preordered camera I guess. Body made a measurable difference though. The difference observed with the 300mm was greater than any other lens. I never tested the theory that the drop in filter was required so can't say for sure on that. I paid the seller to send it to Pentax in the UK for a check before selling it to me and had Pentax directly email me the report. All went fine and lens was perfect, I wouldn't hesitate to trust Pentax with handling the lens. Get a hold of a good tech and send it attn to him.
03-28-2012, 02:43 PM   #18
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It requires more - the lens mount assembly is coming loose under the aperture ring assembly - sent to CRIS for estimate. lens took +9 to +10 to align which I could live with, the camera wobbling on the lens mount I cannot. See how it goes.
03-29-2012, 08:01 AM   #19
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I'm interested to hear how that goes, as I may need to send mine in one day.

03-29-2012, 03:24 PM   #20
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I will keep you apprised, at least I got it off someone that I think will stand by the sale which is what kept me from buying one of these in the past - see how it goes with CRIS - should be next week when I get an answer.

I know you have both the 600 and the 300 - looks like the aperture assembly is more like the 85 F1.4 than the 600 which is slightly different. Is your 300 tight by the bottom of the aperture ring? This one I thought my mono-pod was clacking last Sunday as I heard a noise as I walked around with the lens nestled on my shoulder - then I noticed the entire lens mount assembly was loose - not just the mount - the entire assembly where it goes into the lens body I packed up and went home. I do not think this is a big deal, the lens might have been CLA'd prior to sale and screws left loose - this is what I am hoping is all that is the matter. Might also explain the back focus issue but as long as I could adjust that out I was good as the lens is clean - a lens falling apart on me I am not good with at all.
04-03-2012, 06:16 PM   #21
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I think I may have a back focus issue with an FA77 ltd I just bought from B and H about a month ago. I would have never noticed it as soon as I did if it weren't for the split prism focus screen I installed. All the other auto-focus lenses I have focus correctly with vertical lines matching up in the viewfinder. Not the 77. I own a K-x and was wondering if I should contact Pentax and send it in, or if I should attempt to change the setting using a debugger.

One question...if I go into debug and change the focus for this lens, will it change the focus issue for all the other lenses? Will it be a global change?
.
04-04-2012, 04:12 PM   #22
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If the image is not focused when the prism says it is, that is not a fault of the lens - it means your screen isn't shimmed properly. If you've never noticed this before, it could be that this is the only lens you have that has shallow enough DOF to show the discrepancy. In any case, no sort of software adjustment will change that - the screen has to be re-installed. Assuming, of course, your test was performed properly. You might consider posting a new thread, since this discussion doesn't relate to this thread.
04-05-2012, 12:42 PM   #23
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