Is there life after aperture block failure?

TacticDesigns wrote:

Futax wrote:

TacticDesigns wrote:

Futax wrote:

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.

+1

I think LOL that is exactly what I was asking and trying to find out. Thank you!

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.

That is interesting.

I have to try out my ist DS and K100d to see if it does that too.

Ok.

I tested this out on my Pentax ist DS and Pentax K100d.

For Av mode with Pentax-A lenses . . .

1. When I set the lens to "A", I can adjust aperture via. the e-dial and take a picture. Aperture changes.

2. When I try to set the aperture on the lens and take a picture in Av, all the pictures are taken at the largest aperture, regardless of where I have the aperture dial set on the lens. Aperture setting is not recorded in EXIF.

For Av mode with Pentax-M lenses . . .

1. M lenses don't have an "A" position, so not possible to set it to "A". LOL.

2. When I change the aperture on the lens, all pictures get taken at the same shutter speed, and all seem about the same brightness. So I am assuming that all the pictures, regardless of the aperture ring setting, are being taken at the largest aperture. Aperture setting is not recorded in EXIF.

For M mode with Pentax-A lenses . . .

1. When I set the lens to "A", I can adjust aperture via. the e-dial and then take a stopped down meter reading by pushing the AE-L button. (Green button on newer models.)

2. When I set the aperture with the aperture ring on the lens, I can take a stopped down meter reading by pushing the AE-L button. Aperture setting is not recorded in EXIF.

For M mode with Pentax-M lenses . . .

1. M lenses don't have an "A" position, so not possible to set it to "A". LOL.

2. When I set the aperture with the aperture ring on the lens, I can take a stopped down meter reading by pushing the AE-L button. Aperture setting is not recorded in EXIF.

When I take the lens off and push and put the camera in Av mode, when I press the AE-L (Green) button, the aperture lever does not move. When I fire the shutter, I can see the aperture lever move, but according to the testing above, it does not stop down a Pentax-A or Pentax-M lens.

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.

+1

From my testing above. I don't think this is happening.

Well, it won't if you're not using a K-50.  That's the thing - the K-50 behaves differently from most other (or at least, most other earlier) Pentaxes.  Which allows you to use Av mode with a K-50 with aperture block failure, with more accurate exposure being a bonus.