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06-24-2014, 10:38 PM   #1
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K-3 Won't Recognize...

manual lens(FL not displayed and my Tamron 135 2.5 will only go to 4.0).

06-25-2014, 08:34 AM   #2
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I have no idea what animal your Tamron 2.5/135 is.

Maybe this lens does not offer any information to the body?
With Pentax lenses, only the focal length of A type or newer lenses is known to the body.

And even then, with lenses where the widest aperture is not a common value, the displayed and used aperture may not be correct.
However, this does not influence correct exposure.

If your lens offers the "A" contacts, maybe they need some cleaning/de-oxidation?
06-25-2014, 09:09 AM   #3
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Adaptall? If so, wiggle it a bit on the camera. The Adaptall-2 adapter for Pentax PK/A is very flaky in reporting aperture. At least, my copies are. The cleaning suggestion, above, is a good idea also.

There are several threads in PentaxForums on the vagaries of the Adaptall PK/A. adapter.

If not adaptall, sorry, I haven't a clue.
Good luck.

06-25-2014, 09:57 AM   #4
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Some of the Tamron 'A' adapters have a very thin coating on the pins that must be gently scraped off one pin. There is a Thread by User hinman (search Threads under USERName as Posts) in the MF Lens Discussion Forum that shows which one.

All of my Tamron Adaptall-2 lenses 'work' (aperture adjustment using the e-dial) with my K-3, K-01 and K10D using the 'A' adapter but are reported only as a generic 'A' lens in EXIF.

06-25-2014, 03:09 PM   #5
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QuoteOriginally posted by tabl10s Quote
FL not displayed
That is the expected behavior. Focal length is only available to the body with AF lenses. Non-AF lenses lack the data pin.

As for the maximum f/4 from your PKA adapter...Is the aperture ring locked into the "AE/32" position?* If it is only at the f/22 position the mount may erroneously identify as an A lens with f/4** max - f/22 range. Be sure too that BOTH tabs of the adapter are seated into position on aperture ring. There have been reports of defective PKA adapters always reporting as f/4 max. Let's hope yours is not one of them.

Link to Hin's Adaptal-2 PKA fix page easy with the scraping and only do it at the point indicated and only if you cannot get consistent detection as an "A" contact lens. That is all it fixes. The points in the illustration are countersunk screw heads, not contacts. For an explanation as to why this works, see: LINK

Also, FWIW, my PKA adapter is just plain flaky off the "AE" setting when mated to any of my "A" contact bodies. As noted in a few of the comments in the link above, there is a benefit to engaging the "AE" before mounting the lens and simply leaving it there.


* The lock/release is a black tab at lower left on the adapter

** sometimes f/3.5...go figure

Last edited by stevebrot; 06-25-2014 at 04:57 PM.

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