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Old Aug 10, 2008, 2:20 PM   #1
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Here are 6 photos taken with a TX screw mount Vivitar 300mm f/5.6 lens. No pin to link it to the camera but in AV mode I still don't push a bunch of buttons to get the camera to help with the exposure. I set the Aperture and the camera reads the available light and sets the shutter speed.

This first one is set at f/5.6 and the camera set the shutter speed at 1/750.
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Old Aug 10, 2008, 2:22 PM   #2
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This one is set at f11 and no green button pushed. Also in AV and the shutterspeed set by the camera is 1/125 second. The camera is slowing the shutter down to compensate for the lower light level without me doing anything.
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Old Aug 10, 2008, 2:27 PM   #3
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Our cameras work the same here Dawg. If the aperture lever is not present then Av mode will work fine as the camera cannot hold the aperture open until you press the shutter.

I am going to play some more with mine and see if I can figure out what the difference is between our experiences with the M lenses.

Tim
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Old Aug 10, 2008, 2:27 PM   #4
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In this one I set the f stop to f/22 and the camera set the shutter speed to 1/30 second. Remember this is a screw mount with a K-mount adapter. No Green button or AE-L button pushed. But the camera is still compensating to give a good exposure. All I've done with these 3 is push the shutter release half way to allow the camera to aid me in focusing and to get a reading on the exposure. Then I shoot the photo.

Dawg
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Old Aug 10, 2008, 2:35 PM   #5
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NonEntity1 wrote:
Quote:
Our cameras work the same here Dawg. If the aperture lever is not present then Av mode will work fine as the camera cannot hold the aperture open until you press the shutter.

I am going to play some more with mine and see if I can figure out what the difference is between our experiences with the M lenses.

Tim
Tim the Aperture is full open on the manual lenses till you push the shutter button then the camera trips it to the set aperture. If you set it at f/8 and look into the lens you'll see it is opens all the way. But when you trip the lens it moves to the set aperture for a split second so the camera gets the right exposure. If you have a manual lens that has sticky aperture blades then it will stay open all the time. The aperture blades cannot move to the correct position because they are stuck in place. In this case pushing all the buttons in the world won't move the aperture and yes they will stay wide open all the time no matter what. Have a good day my friend as I plan on a long nap now....All this typing is killing me!! LOL:lol::lol:

Dawg
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Old Aug 10, 2008, 3:16 PM   #6
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Dawg, I am completely befuddled. My K100d, K10d, and K20d all work the same way with P/K mounts. I have been through the menu and looked for any setting that I have previously overlooked without success. I can find nothing but your camera is working competely differently than mine.

Here is a set ofshots taken with a P/K mount Tokina 400mm. The first pic is the camera mount. Allfour shots were taken in Av mode. There is obviously no A setting on the lens. The three shots were taken at f/5.6, f/8, f/11, and f/22. Exif should be intact. While shutter speed did change slightly (the available light changed slightly with cloud cover) it moved from 1/125 at f/5.6 and f/8 to 1/160 at f/11 and f/22.

I did confirm that the aperture blades are working freely and the camera does stop down in M mode.

With a P/K mount lens the behavior I observe in Av mode is the following: The camera does meter automatically but it does not stop the lens down to whatever you have the aperture ring set to. Now if I could make mine work the same way yours is apparently working I would be very happy as Av mode is my favorite anyhow.

Any other Pentaxians have a clue what I must be doing wrong?

Tim

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Old Aug 10, 2008, 3:19 PM   #7
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5.6 and 1/125 seconds. Av mode:
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Old Aug 10, 2008, 3:19 PM   #8
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f/8 and 1/125 seconds. Av mode:
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Old Aug 10, 2008, 3:20 PM   #9
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f/11 and 1/160 (due to slight change in the light. If it was aperture, the shutter speed would go the other direction)
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Old Aug 10, 2008, 3:21 PM   #10
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f/22 and 1/160
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