Originally posted by zosxavius
I just bought an tamron adaptall 60-300 sp as well as a 28mm 2.5. When using the adapter that this guy had I couldn't get it to stop down with the stop down function on my K-7. The lens refused to stop down when taking pictures. The connecting pin between the adapter and the lens is still there and functional. I took the lens off and just put the adapter on the body. Tried toggling it there. Nothing. I do have it set to use aperture other than A in the menu, and it prompts me for the mm when I start the body up. Nothing I can do will stop this lens down. The adapter didn't have any contacts, but it did have the aperture lever and it liked into the aperture lever on the body. So I'm guessing this was the older K/M style adapter. It would be excellent if I could figure out how to get stop down metering to work. I'm in M mode, but the aperture lever won't toggle no matter what I try. I left the adapter there thinking I needed a different one or that it wouldn't work and he dropped the price substantially as a result. I paid like $50 for both. Here's the real question. If that ring is a genuine adaptall2 k m ring, it should work just like any Pentax m lens. Why won't it toggle aperture. Is there a set of pins on the body that needs to be crossed for that to toggle? Bad contact somewhere? It was a really clean looking adapter.........I don't care about the automatic controls....stop down is fine. I can't justify paying $100 for an adapter that doesn't give me any advantages since these lens are manual aperture control only. Can someone help out here?
Thanks!!!!!!
I have had some issues with these adaptors from time to time. Here is what I find. Many times there seems to be an allignment issue with the A pin, where it looses contact and the aperture shows F--. THis can be rectified by slight rotational pressure on the lens.
The other issue is more serious, where the lens either does not make contact with the A pin, or the aperture does not read correctly and is limited to F4 (all pins open) due to a bad contact between internal parts of the adaptor. I fixed this on one mount by placing a small metal shim between parts of the mount to connect them.
Also note that the smallest maximum aperture the mount supports is F4, so a slower lens will report F4 unless you modify the mount. I use nail polish for this