Is there life after aperture block failure?

TacticDesigns wrote:

Massao wrote:

...

I think both of you are right, but just happen to be talking about different things.

I want to test one thing on my Pentax cameras tonight with a Pentax-M lens and then I'll post. I want to confirm one thing with Pentax-M lenses in manual exposure mode. I also want to confirm something that someone told me a long time ago about how to make a Pentax-M lens act like an adapted lens to get a sort-of (not so consistent) aperture priority mode on Pentax dSLR cameras.

But the "one" question I have is . . . if a Pentax camera suffers aperture block failure, then when you press the shutter button (to take a picture) when the camera is in manual exposure mode, does the aperture block motor actuate and attempts to stop down the lens? Basically, I want to know if the motor moves, even if it is not doing exactly what it is supposed to do. And . . . even if the cameras suffers ABF, does it still let you take a picture in manual exposure mode.

Take care & Happy Shooting!

Please see my last post to flektogon.  Basically, with an M lens, regardless of aperture block failure (and with any Pentax camera), in M mode, you will need to use the "green button" prior to the shot in order for the camera to stop down the lens and evaluate the correct exposure (but is subject to errors due to the metering having to work properly with varying apertures).

The aperture block failure just means that the camera will operate the stop-down lever FULLY all the time, instead of trying to control the exact aperture.  Doesn't affect the above.

Never mind, with M lenses the camera can't set the correct aperture anyway - those lenses control the aperture themselves - all that's required is that the camera operate the lever fully when taking the shot (like all legacy Pentax cameras).  But the K-50 (though it isn't meant to) actuates the lever when taking a shot anyway - regardless of exposure mode.  So you take advantage of this by using Av mode.  The camera doesn't know the aperture you set, so you have to compensate.  Simple as that.  An f4 lens set to f8 will need +2EV compensation.

This is a very useful "feature" of the K-50 (and hopefully the K-30, K-500 etc.) as you get accurate exposure and more straightforward shot taking (arguably).