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12-26-2010, 02:27 AM   #16
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QuoteQuote:
Yusuf: Does electronics has any role into this?
Absolutely. But I find this below somewhat confusing, and a possible clue:

QuoteQuote:
Yusuf: When I try to change the aperture, camera does not change aperture and stays at 2.8 in back LCD (k-x). However it shows the aperture change in viewfinder and changes shutter speed also - which is definitely not correct. Resulting photos are naturally overexposed. EXIF shows f2.8.
Are you saying, no matter what aperture you select, as evidenced from the viewfinder, all shots are done wide-open?

12-26-2010, 02:34 AM   #17
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QuoteOriginally posted by Jewelltrail Quote
Absolutely. But I find this below somewhat confusing, and a possible clue:

Are you saying, no matter what aperture you select, as evidenced from the viewfinder, all shots are done wide-open?
Exactly, aperture change is not shown in the back LCD, back LCD always shows f2.8. But it does show change in shutter speed if I try to change aperture. Additionally, in viewfinder, it shows change in both - shutter speed and aperture. And when clicked, it shots wide-open.

Btw, what role does electronics has to play in this? I thought camera will be moving lever to control the aperture like it does in A lenses. And since camera works fine with other lenses, it should be able to do it with this lens too. May be I missing some important information.

Yusuf
12-26-2010, 02:35 AM   #18
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You can try, very gently, with an eraser of a pencil head, to clean the contact points for aperture: body and lens side. I m not sure which pin it is, (if there is a pin for A) but you can gently rub each pin without causing any harm. There may just be some oil or muck on a pin.

Mike, I wish I knew more about how the aperture lever in this setup is actually stopped down. It could be the camera manually moves the lever on the lens in response to you selecting the aperture, in which case it makes no sense that it works on other lenses, but not on this one, since you clearly show the lever actuates freely, responsively, on the lens.

An alternative is the lens provides electronic feedback to the body concerning aperture position, in which case you have a possible explanation as to why only the 17-50 fails to stop down on your Kx, while other lenses do not. I dunno--I do not know enoguh to say any more.

Perhaps someone here can help???

Can you post a few shots, with exif intact, showing different shutter speeds, but always wide open aperture? If the shutter speeds are 1 stop apart in each shot, and the lens truly never moves from wide open, we should see shots at precisely 1 stop intervals, so long as you control light indoors--in the dark. You could set this up and prove, without a doubt, that aperture never leaves wide open on Kx, even when you select different apertures via various modes. Wish I had a more simple suggestion.

Last edited by Jewelltrail; 12-26-2010 at 03:35 AM.
12-26-2010, 03:49 AM   #19
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One final thing--you can't have both of these conditions existing together, if the body acting alone, independent of the lens, actuates aperture lever:

1) The lens' aperture mechanism operating correctly
2) Other lenses functioning properly on the same body

Please, let us know how you make out--tx.

JT

12-26-2010, 04:20 AM   #20
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I'm having a similar problem with the k-x, the difference being that no modern lens works properly. The aperture changes in the viewfinder display, but not on the back display. Exposures vary, they might come out at the viewfinder stop, but most of the time are fully open. M-lenses seem to work in their usual manner. A bit earlier this was worse in that AF did not work and the shutter refused to operate unless an M42 (or no lens) was mounted.

Because the symptoms have varied this could be a flaky contact somewhere inside the body. Cleaning the lens/mount contacts did not help, also the modern lenses work fine on the K-5 which I got at the time the k-x seemed to have gotten unusable. I suppose I'm going to send k-x in for warranty repair; I would rather have avoided this as this is apparenty a grey import where this needs to sent back to the seller in UK. Another theory I have entertained has been a firmware glitch where persistententy stored parameters have gotten in an invalid state. In my case it might be worth a try to copy these from a working k-x using the debug menu functions (unfortunately I don't have a working k-x handy).

Last edited by jolepp; 12-26-2010 at 06:46 AM.
12-26-2010, 06:44 AM   #21
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QuoteOriginally posted by Jewelltrail Quote
One final thing--you can't have both of these conditions existing together, if the body acting alone, independent of the lens, actuates aperture lever:

1) The lens' aperture mechanism operating correctly
2) Other lenses functioning properly on the same body

Please, let us know how you make out--tx.

JT
Not sure if I understood correctly but as I mentioned, this is a particular problem with this lens only. All other lenses works like a charm. I tried removing this lens and putting other and they work fine, as soon as I put this one, it does not work so I have no reason to doubt the body.
12-26-2010, 04:35 PM   #22
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This is very dumb of me to ask, please forgive in advance: do the optical and digital stop down preview work? How abt when you put the camera on M and do a stopped down meter reading with the green button? Does the lens stop down properly in those situations?
12-27-2010, 06:56 AM - 1 Like   #23
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Here's another dumb question- if you still have the k100d in your sig line, does the lens work on that body?

12-27-2010, 07:11 AM   #24
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QuoteOriginally posted by conradj Quote
This is very dumb of me to ask, please forgive in advance: do the optical and digital stop down preview work? How abt when you put the camera on M and do a stopped down meter reading with the green button? Does the lens stop down properly in those situations?
I haven't tried green button but in any mode aperture does not change. Although I will check that out when I reach home tomorrow but since it remains at 2.8 I think it will not make any difference - it does not need to stop down since aperture is already at 2.8.

QuoteOriginally posted by bimjo:
Here's another dumb question- if you still have the k100d in your sig line, does the lens work on that body?
No, it does not work with other body too.
12-27-2010, 07:59 AM   #25
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QuoteQuote:
Yusuf: Although I will check that out when I reach home tomorrow but since it remains at 2.8 I think it will not make any difference - it does not need to stop down since aperture is already at 2.8.
Actually, when a 2.8 lens is @ 2,8, it can only stop down from there. The term stopping down, means to move to smaller apertures, from larger ones.

QuoteQuote:
Yusuf: No, it does not work with other body too.
If it is not working on the other body, you can almost bet it is the lens--just be sure it actually does not stop down.

Also, I found this link which will enable you to determine if your lever is in fact assembled correctly--excellent pics here too. Keep us up to date--tx.

Flickr: Ken Sekiguchi's Photostream
12-27-2010, 08:51 AM   #26
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QuoteQuote:
Jewelltrail:
Mike:

How do you know the aperture is snappy? The 17-50, unfortunately, has no aperture ring. When the lens is dismounted, is the aperture fully stopped down?

JT
Mike:

Above you answered yes when I asked if you the lens is fully stopped down, when the lens is off the body. But now, I can see, you are confused with terminology--but we will get through this.

When the lens is off the body, hold it up to the light and you should see a tiny hole, through which light can pass. This is fully stopped down and is the correct position of the blades when lens is off the body. When you move the lever, you are opening the blades, or moving to larger apertures.

Now the $100,000 question is: with the lens in your hands, off the body and held up to light, is the lens fully stopped down, with just a little hole through which light can pass?
JT
12-28-2010, 10:03 PM   #27
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Mike:

You have retreated to silence--how are you making out?

JT
12-29-2010, 05:38 AM   #28
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JT, I guess you probably wanted to ask me (OP) - anyway, I was out so couldn't respond. Here are some pictures

First one is mount - looks normal to me. Can you please compare it with your 17-50mm - do you see any abnormalities?



2nd one is when lens removed - it's stopped down as expected.



3rd one, is when I move the lever manually to the other side



I tried to clean lens contacts but it did not made any difference. But I am still hopeful because there is a minor thing which I am missing.

Yusuf





QuoteOriginally posted by Jewelltrail Quote
Mike:

You have retreated to silence--how are you making out?

JT

Last edited by yusuf; 12-29-2010 at 05:43 AM.
12-29-2010, 07:10 AM   #29
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QuoteQuote:
Yusuf: JT, I guess you probably wanted to ask me (OP) - anyway, I was out so couldn't respond. Here are some pictures

First one is mount - looks normal to me. Can you please compare it with your 17-50mm - do you see any abnormalities?
Thank you for getting back to us. Yes, I do see something which looks out of the ordinary to me (see your first pic). The little, black plastic guide, behind the aperture lever, has a bend in it which mine does not have. It is hard for me to believe, though of course it is possible, that that tab is of a different design than mine. My guess is the tab was damaged somehow, either from a drop, or from someone carelessly mounting the lens & hitting the tab on the body's face.
12-29-2010, 10:14 AM   #30
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QuoteOriginally posted by Jewelltrail Quote
Thank you for getting back to us. Yes, I do see something which looks out of the ordinary to me (see your first pic). The little, black plastic guide, behind the aperture lever, has a bend in it which mine does not have. It is hard for me to believe, though of course it is possible, that that tab is of a different design than mine. My guess is the tab was damaged somehow, either from a drop, or from someone carelessly mounting the lens & hitting the tab on the body's face.
May be that's the picture, otherwise tab looks pretty normal to me. Let me take some more pics and post is again. Apart from that what are other possibilities? If you like me to try something, I can and post the results.
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