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kypfer
Joined: 27 Sep 2017
Posts: 516
Location: Jersey C.I.
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 Posted: Wed Mar 18, 2020 5:19 pm Post subject: Kiron 28mm f/2 |
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kypfer wrote:
Does anyone have any disassembly experience with this lens?
I acquired an all-manual one in PK mount a few weeks ago, for use on my Pentax, did the usual cursory checks which all seemed OK and put it to one side 'till I wanted to play with it.
When I took it out the other evening I was surprised to find the lens focussed at infinity when set at about 2m on the scale. No big deal and not something I can't live with, for what I want it for. However it'd be so much easier to use if infinity really was infinity (or as close as dammit).
I suspect a thick shim or spacer has been removed from behind the mount, possibly to assist with use on a non-PK camera with adaptor. There's none of the usual scratch-marks or chewed screw-heads to suggest the lens has been totally or even partially disassembled and reassembled incorrectly.
Just hoping someone has experience with this lens, ideally in PK mount, and might be able to confirm the shim/spacer configuration under the mount.
TIA |
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marcusBMG
Joined: 07 Dec 2012
Posts: 1305
Location: Conwy N Wales
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| Posted: Thu Mar 19, 2020 2:05 pm Post subject: |
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marcusBMG wrote:
See my write up here:
https://www.pentaxforums.com/forums/114-maintenance-repair-articles/391582-kiron-vivitar-28mm-f2-24mm-f2-sticky-iris-fix.html
It is the distance scale that has the infinity stop, the position of this is what you need to adjust. Should be straightforward to do. Basically you must remove the nameplate/front end. Then set the lens at infinity and see which way you need to move the distance scale to give you a bit more helicoid movement there, then slacken the set screws on the distance scale and rotate it a few mm.
_________________
pentax ME super (retired)
Pentax K3-ii; pentax K-S2; Samsung NX 20; Lumix G1 + adapters;
Adaptall collection (proliferating!) inc 200-500mm 31A, 300mm f2.8, 400mm f4.
Primes: takumar 55mm; smc 28mm, 50mm; kino/komine 28mm f2's, helios 58mm, Tamron Nestar 400mm, novoflex 400mm, Vivitar 135mm close focus, 105mm macro; Jupiter 11A; CZJ 135mm.
A classic zoom or two: VS1 (komine), Kiron Zoomlock... |
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kypfer
Joined: 27 Sep 2017
Posts: 516
Location: Jersey C.I.
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| Posted: Thu Mar 19, 2020 4:01 pm Post subject: |
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kypfer wrote:
Many thanks for the details 
Careful examination with a loupe shows the tiny grub-screw does appear to have been interfered with, so that's probably where the problem lies. At the moment, I don't have a screwdriver quite small enough to tackle that screw, but I'll keep note of the details and see what I can find next time I'm shopping  |
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marcusBMG
Joined: 07 Dec 2012
Posts: 1305
Location: Conwy N Wales
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| Posted: Thu Mar 19, 2020 4:36 pm Post subject: |
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marcusBMG wrote:
Yeah it's pretty small. You can pick up cheap "jewellers screwdriver(s)", then file/dremel one to size. Take care not to trash the grub screw. if it's already been removed once then the thread locker grip should have been broken. Once the screwdriver is the right size, then feel its engagement in the screw and carefully apply gently increasing rotation until you can feel the screw turn, while maintaining a firm downward press to keep the tip in the slot.
_________________
pentax ME super (retired)
Pentax K3-ii; pentax K-S2; Samsung NX 20; Lumix G1 + adapters;
Adaptall collection (proliferating!) inc 200-500mm 31A, 300mm f2.8, 400mm f4.
Primes: takumar 55mm; smc 28mm, 50mm; kino/komine 28mm f2's, helios 58mm, Tamron Nestar 400mm, novoflex 400mm, Vivitar 135mm close focus, 105mm macro; Jupiter 11A; CZJ 135mm.
A classic zoom or two: VS1 (komine), Kiron Zoomlock... |
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kypfer
Joined: 27 Sep 2017
Posts: 516
Location: Jersey C.I.
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| Posted: Thu Jun 18, 2020 11:00 am Post subject: |
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kypfer wrote:
| marcusBMG wrote: |
| Yeah it's pretty small. You can pick up cheap "jewellers screwdriver(s)", then file/dremel one to size. Take care not to trash the grub screw. if it's already been removed once then the thread locker grip should have been broken. Once the screwdriver is the right size, then feel its engagement in the screw and carefully apply gently increasing rotation until you can feel the screw turn, while maintaining a firm downward press to keep the tip in the slot. |
Screwdriver acquired - lens adjusted
Thank you again! |
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marcusBMG
Joined: 07 Dec 2012
Posts: 1305
Location: Conwy N Wales
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| Posted: Thu Jun 18, 2020 12:05 pm Post subject: |
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marcusBMG wrote:
You're welcome
_________________
pentax ME super (retired)
Pentax K3-ii; pentax K-S2; Samsung NX 20; Lumix G1 + adapters;
Adaptall collection (proliferating!) inc 200-500mm 31A, 300mm f2.8, 400mm f4.
Primes: takumar 55mm; smc 28mm, 50mm; kino/komine 28mm f2's, helios 58mm, Tamron Nestar 400mm, novoflex 400mm, Vivitar 135mm close focus, 105mm macro; Jupiter 11A; CZJ 135mm.
A classic zoom or two: VS1 (komine), Kiron Zoomlock... |
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tomasg
Joined: 01 Nov 2009
Posts: 1135
Expire: 2014-04-28
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| Posted: Thu Jun 18, 2020 1:54 pm Post subject: |
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tomasg wrote:
It s nice to see feedback posted from somebody that asked for help, it doesn t happen that often. |
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