Is Av possible on Super Takumar M42?

[Stratario]

I need help again on the use of old lenses. I just bought a genuine Pentax adapter and my first m42 lens. It's a Supar Takumar 105mm F2.8. The lens has a sliding switch on it with M and A shown on the sides of the switch. So far I can get it to work when I put the switch on the M setting and set the camera shooting mode to M as well. Then I use the green button for exposure metering. I am wondering if there is a way that I can use the Av mode on the camera and perhaps use a flash. Thanks in advance for your help.

[Groucho]

You will want to leave the switch in "M" (otherwise the lens will always be "wide open".)

You should be able to shoot in Av mode just fine, it will meter full-time and should be more or less accurate while you change the aperture via the ring on the lens itself.

For flash, you'll probably need to use an older, manual flash where you can pick the exactly shutter/aperture/ISO speeds and match the camera to those.

[Stratario]

Thanks. That was very helpful.

[Zewrak]

I have noted that at 2.8-3.5 the metering is rather accurate (on K10D). less then 2.8 it underexpose about half a step per half a step you go down. Above 3.5, it overexpose with about half a step per 1.5 step you go above.