K-7 and bellows : aperture problem

**fs999** · 01-06-2010, 03:39 PM

There seems to be a problem with K-7 and my Novoflex bellows. In manual mode the aperture is not closing when taking the photo and neither with the optical preview...

I tried with my K 50mm f:1.2, the aperture is closing fine but not when mounted on the bellows.

Is it possible that the K-7 needs one or more lens information contacts ?
Because the mount on the bellows is painted in black...

I had no problems with my K20D even with DA lenses which are closing at maximum...

Fogel70 · 01-06-2010, 04:02 PM

Are you sure the bellows has the mechanical linkage for stopping down the lens from the camera? I think most bellows has a manual control to stop down the lens on the bellows itself.

StealthNet · 01-06-2010, 05:13 PM

A story before getting to the subject: I dropped my case from a half a meter fall. It is a tamrac case with my K-7 (with a tamron 18-250 attached + grip), an 80-320mm, a Metz flash and some filters.

It was enough to slightly "bend" the lens mount (not visible with a naked eye). Body mount was fine. I´ve got 4 days into complete madness before figuring out what happened. Symptom: camera would take low light pics ok, but daylight (sunlight) pics *always* overexposed.

When I carefully examined the tamron 18-250, I´ve found that the mechanical aperture level was stuck: it is supposed to return to the closed position.

Simply took the lens apart. After removing the screws from the lens mount, I saw that the bend was keeping the inner aperture ring from running (friction).

Now, to the point: remove the lens and check the mechanical aperture leveler. If you carefully move it, you´ll see that the aperture blades will open. Release it and it should return to the closed position. If it is not returning by itself, then I think that might be the problem.

Good luck!

blende8 · 01-07-2010, 02:41 AM

Originally posted by fs999

Is it possible that the K-7 needs one or more lens information contacts ?
Because the mount on the bellows is painted in black...

Yes, that is possible.
Try shortening the contacts with some aluminium foil.
If that works, you can remove the color on your bellows.

**fs999** · 01-07-2010, 02:03 PM

It works with the aluminium foil... and only in manual mode !

Thank you very much blende8 !

01-06-2010, 03:39 PM	#1
fs999 Loyal Site Supporter Join Date: Jul 2008 Location: Luxembourg Photos: Gallery Posts: 8,635	K-7 and bellows : aperture problem There seems to be a problem with K-7 and my Novoflex bellows. In manual mode the aperture is not closing when taking the photo and neither with the optical preview... I tried with my K 50mm f:1.2, the aperture is closing fine but not when mounted on the bellows. Is it possible that the K-7 needs one or more lens information contacts ? Because the mount on the bellows is painted in black... I had no problems with my K20D even with DA lenses which are closing at maximum...

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01-06-2010, 04:02 PM	#2
Fogel70 Pentaxian Join Date: Sep 2009 Location: Stockholm, Sweden Photos: Albums Posts: 3,062	Are you sure the bellows has the mechanical linkage for stopping down the lens from the camera? I think most bellows has a manual control to stop down the lens on the bellows itself.

01-06-2010, 05:13 PM	#3
StealthNet New Member Join Date: Nov 2009 Posts: 4	A story before getting to the subject: I dropped my case from a half a meter fall. It is a tamrac case with my K-7 (with a tamron 18-250 attached + grip), an 80-320mm, a Metz flash and some filters. It was enough to slightly "bend" the lens mount (not visible with a naked eye). Body mount was fine. I´ve got 4 days into complete madness before figuring out what happened. Symptom: camera would take low light pics ok, but daylight (sunlight) pics always overexposed. When I carefully examined the tamron 18-250, I´ve found that the mechanical aperture level was stuck: it is supposed to return to the closed position. Simply took the lens apart. After removing the screws from the lens mount, I saw that the bend was keeping the inner aperture ring from running (friction). Now, to the point: remove the lens and check the mechanical aperture leveler. If you carefully move it, you´ll see that the aperture blades will open. Release it and it should return to the closed position. If it is not returning by itself, then I think that might be the problem. Good luck!

01-07-2010, 02:41 AM	#4
blende8 Veteran Member Join Date: Feb 2007 Location: Bremen, Germany Photos: Albums Posts: 1,521	Originally posted by fs999 Is it possible that the K-7 needs one or more lens information contacts ? Because the mount on the bellows is painted in black... Yes, that is possible. Try shortening the contacts with some aluminium foil. If that works, you can remove the color on your bellows.

01-07-2010, 02:03 PM	#5
fs999 Loyal Site Supporter Join Date: Jul 2008 Location: Luxembourg Photos: Gallery Posts: 8,635 Original Poster	It works with the aluminium foil... and only in manual mode ! Thank you very much blende8 !

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