Originally posted by Pentaxoid How can it be used in Av mode like M42? The camera body can control the aperture on this lens? Most M42 cannot do that.
As it is russian made is there any radioactive element or whatever?
Of course the camera cannot control the aperture of M42 lenses. But this does no mean that the lens cannot be used in Av mode. Any M42 lens can be used in Av mode on a Pentax DSLR by changing the aperture from the lens. With M42 you set the aperture on the lens and camera does the metering automatically in Av mode, same thing with this lens.
Not sure if there are any radioactive elements inside, but the lens glows in the dark (it helps a lot in low light photography). I was using this lens to take photos of my dog and now the dog has a skin cancer. And for some reason the battery of my Pentax K7 never goes flat when I use this lens. But no, I don't think it's radioactive.
BTW The lens comes with special case made of lead with cool looking logo (yellow circle with 3 black triangles inside), will post photos.
Edit: I was just kidding about the radioactive stuff. But, as far as I know the lens does not have radioactive elements.