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02-09-2017, 04:48 AM   #1
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Tokina 28mm SL28 F2.8 - aperture issue

Hi,

I have this lens, Tokina 28mm f2.8 (SL28 version) with 'A' setting. When I connect this lens to my K3 while the A setting is on, I couldn see the Aperture value from 'F4' only. Camera wont let me go to the widest aperture f2.8. What should be the problem? I think the lens has been modded to remove the shroud that prevents the lens from mounting on later DSLRs as it obstructs power-zoom of camera. Any suggestions??

02-09-2017, 07:36 AM   #2
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This is my sl28. The PK-AR (pentax/ricoh) mount has 6 contacts: 2 insulating I; 3 conducting C plus the pin that is activated (protrudes) when aperture ring is clicked into "A" position..
If the mount was removed then it is possible that one of the conducting contacts was affected in some way. How do they look?
However it is not necessary to remove the mount to diy the baffle, that comes off by itself.
PS to Brian: any ideas what the cutout at the twenty of position might be for?
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02-09-2017, 08:44 AM   #3
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Wow! that's lot of knowledge for me . I quickly checked my lens mount and I can clearly see one of the C contacts are missing. May be the reason. While it may not be required.. is there any way to set it back?

Missing contact

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28mm, 28mm sl28 f2.8, aperture, camera, f2.8, lens, pentax service, repair, service, sl28 f2.8 aperture, tokina, tokina 28mm sl28, warranty
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