[Wheatridger]

Here's a stumper-- I'm new to Pentax so there might be a simple answer lurking. My 50/1.4 Super -Takumar exposes normally, I think, when attached to my new K5IIs with a genuine Pentax M42 adapter. But when I screw my Super Takumar 135/2.5 onto that same adapter, the camera won't fire, and the rear screen winks out when I press the shutter button. Both lenses are of the same generation, so I'd expect them to work the same way, right? With the 135, the F-- warning blinks in the OVF, while with the 50 it remains steadily lit.

Any answers, or educated guesses?

[Adam]

Here's a stumper-- I'm new to Pentax so there might be a simple answer lurking. My 50/1.4 Super -Takumar exposes normally, I think, when attached to my new K5IIs with a genuine Pentax M42 adapter. But when I screw my Super Takumar 135/2.5 onto that same adapter, the camera won't fire, and the rear screen winks out when I press the shutter button. Both lenses are of the same generation, so I'd expect them to work the same way, right? With the 135, the F-- warning blinks in the OVF, while with the 50 it remains steadily lit.

Any answers, or educated guesses?

The lens contacts on the mount might be getting shorted by the lens that doesn't work. You've followed all of these steps, right?

[Wheatridger]

Thanks- changing the menu setting "Use aperture ring" helped a lot, and now both lenses are usable. I still wonder why the 50 was useable without that change, however.

[Wheatridger]

Today I got some pretty good results with the Super Tak 135/2.8, heavily cropped. Working without auto-aperture seemed very natural. Surprisingly, the AF confirmation kept on beeping down to F8 and below! I just have to pay stict attention to what I'm focusing on.

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