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Old Aug 10, 2008, 3:33 PM   #11
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I also ran the same test using a KA mount lens, my 105mm macro. I took the lens off the A setting and manually set the aperture on the lens ring, but I left the lens in Av mode. I observed the exact same behavior except that, since there is an electronic contact, the lens reported aperture data. No matter what aperture I set the ring to, the lens reported f/2.8, which is actually correct since the camera was not stopping the lens down.

I am only more confused now, as my only theory was that you might be inadvertantly using a KA lens without noticing it.

f/2.8 and 1/1000.
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Old Aug 10, 2008, 3:33 PM   #12
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f/5.6 and 1/1000
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Old Aug 10, 2008, 3:34 PM   #13
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f/11 and 1/1000
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Old Aug 10, 2008, 3:35 PM   #14
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f/22 and 1/1250 (again, the light was subtly shifting)

I am hoping someone else has an answer.

Tim
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Old Aug 10, 2008, 6:07 PM   #15
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One of the things I noticed between your and Dawg's experience in this threadis that he's using a screw mount lens, NOT a K-mount lens. Tim is using a K-mount lens. If I understand things correctly (I don't have any screw-mount lenses) there's nothing between the camera and the lens, so the lens stops down when you turn the aperture ring. K-mount lenses have a lever that the camera operates, so you can focus with the lens wide open, then the camera will stop down the lens when you push the shutter (or at least it does that in M mode - it doesn't do that in any other mode). That's why the difference - if the lens is already stopped down, the camera will meter correctly in AV mode.
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Old Aug 10, 2008, 6:54 PM   #16
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Harriet you missed the other post where I used a Pentax M 50mm f/1.7 lens and got the same results.
http://forums.steves-digicams.com/fo...=80&page=1

I don't know Tim...Do you have your set up in the camera menu to allow use of the Aperture ring?
My camera has done this since day one and I don't know why they all wouldn't. As for using an A lens that is not the way it is. This is a Pentax-M 50mm 1:1.7 all manual lens. But then again it also worked on my f/2 50mm and every one of the Vivitar lens I've put on it!

Dawg

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Old Aug 10, 2008, 6:59 PM   #17
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Dawg, yes, aperture ring is set to permitted. You haven't, by chance, removed the automatic aperture lever from the M lens have you? If the lever is not there my camera will do exactly as you describe. I know we have some other M series lens users on the forum, I am hoping Roy, Tom, or someone else will weigh in.

Tim
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Old Aug 10, 2008, 7:02 PM   #18
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Just took a look into my lens from the front end. The aperture blades are in the position I set but as I move the aperture to a higher value the shutter speed can be heard going to a slower and slower speed as I change the aperture setting. This is in AV mode. With a manual K-mount lens. This is to say it doesn't stop down at the instant of the shutter being released but it is already stopped down to the set aperture. And the camera is still compensating by large changes in shutter speed.

Dawg

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Old Aug 10, 2008, 7:03 PM   #19
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NonEntity1 wrote:
Quote:
Dawg, yes, aperture ring is set to permitted. You haven't, by chance, removed the automatic aperture lever from the M lens have you? If the lever is not there my camera will do exactly as you describe. I know we have some other M series lens users on the forum, I am hoping Roy, Tom, or someone else will weigh in.

Tim
Before mounting the lens I made sure the lever worked correctly. I also checked inside the camera and all is well there as well.

Dawg

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Old Aug 10, 2008, 7:05 PM   #20
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Just took a look into my lens from the front end. The aperture blades are in the position I set but as I move the aperture to a higher value the shutter speed can be heard going to a slower and slower speed as I change the aperture setting. This is in AV mode. With a manual K-mount lens. This is to say it doesn't stop down at the instant of the shutter being released but it is already stopped down to the set aperture. And the camera is still compensating by large changes in shutter speed.


Interesting, and I think this is the explanation. Your lens is functioning as if the lever were not present (not holding the aperture blades open until the shutter is pressed). That being the case, there would be no difference between our cameras. If you have a lens with the lever functioning try the same experiment in Av mode, but I think this must be the answer.

Tim

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