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07-17-2012, 02:59 PM   #1
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Are these "A" lenses?

Hey, guys...

Please help clarify some confusion (on my part) while I wait for the M42 adapter...

I've read through the posts and articles on using my old SMC glass with my new Kr. I see a lot of references to "A" lenses, and I think I understand that to mean lenses with an A/M switch on the aperture ring (if I'm wrong, please be gentle, TIA). But -- here's the confusion -- if these are indeed "A" lenses, I still need to set the switch to "M", yes?

These are the lenses currently waiting their turn for use (all are Asahi Optical, in very good condition; all have A/M switch on the aperture ring):

SMC Takumar 1:3.5/28mm
Super-Takumar 1:2/55mm
SMC Takumar 1:3.5/135mm
SMC Macro-Takumar 1:4/50mm

Thanks for enlightenment...

07-17-2012, 03:10 PM   #2
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In terms of Pentax lenses an 'A' lens is a K-Mount lens with electrical contacts allowing the body to set aperture.

The Takumars you listed are all auto aperture M42 lenses with an Auto/Manual switch. The SMC Taks will have a small switch on the back that will keep it locked in Auto mode unless it is pressed. You should keep these in Manual. The Super Tak can be used in Auto mode to focus and set the aperture, you then switch to Manual to stop down.
07-17-2012, 03:18 PM   #3
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Original Poster
Thanks very much. Now I understand! These are all M42 screw-mount lenses.

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