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03-22-2016, 06:03 PM   #1
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K-3 says F-- with every lens

Last summer, one of my K-3's developed a problem where any lens I put on the camera would register as F--. All of these lenses were fine on my other body, so it must have been a problem with this body. I tried cleaning the contacts myself, first with alcohol and then contact cleaner, neither of which helped. I ended up sending the body off for warranty repair, which fixed the problem. The repair note said that the only things they did were clean the contacts and update the firmware.

Now this same body is having the same problem. Again. I tried cleaning the contacts myself with contact cleaner, which once again didn't help. What am I missing? I'd really rather not have to send the body off for repair again seeing as last time it took Precision two or three months to deal with the problem, which was entirely Precision's fault. I am not pleased.

03-22-2016, 06:43 PM   #2
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Could be a slight imprecision in the mount itself. I would tell them their repair had no effect, and they will likely replace the mount for you. Hopefully the turnaround is not that bad this time!

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03-22-2016, 06:43 PM   #3
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First, make sure your lenses have the aperture ring turned to the 'A' position. If that does not fix the problem, just use a little bit of isopropyl alcohol on a clean cloth and wipe off the contacts on the body and on each lens.
03-22-2016, 06:46 PM   #4
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If it is still under warranty Precision is the only service center that handles warranty work. If it is out of warranty you can send it elsewhere. See the thread Service Centers.

Precision's turn around time seems to have improved. It helps to get Ricoh involved if it takes more than a couple weeks unless parts are needed.

03-22-2016, 06:54 PM   #5
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The F-- error message means that the camera can not control the aperture setting. Check the Custom Setting C4, Item 27, Using Aperture Ring and set it to 2. If the error message persists it may be a fault in the camera. Just my $0.02.
03-22-2016, 11:45 PM - 2 Likes   #6
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QuoteOriginally posted by wtlwdwgn Quote
The F-- error message means that the camera can not control the aperture setting.
It is also a result of the camera censoring the foul language coming from the metering system....
03-23-2016, 05:28 AM   #7
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QuoteOriginally posted by Digitalis Quote
It is also a result of the camera censoring the foul language coming from the metering system....
Yeah, the K-3 is a family camera.
03-23-2016, 08:21 AM   #8
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QuoteOriginally posted by Digitalis Quote
It is also a result of the camera censoring the foul language coming from the metering system....
I thought it was the foul language from the photographer.

03-23-2016, 10:09 AM - 1 Like   #9
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QuoteOriginally posted by Outis Quote
Now this same body is having the same problem. Again. I tried cleaning the contacts myself with contact cleaner, which once again didn't help.
You might want to use a different approach. Typically a light buffing with a clean microfiber cloth should be all that is needed. The F--- display is due to lack of continuity across the "A" contact (* on diagram below) to the mount face.


Image lifted from Dimitrov's K-Mount Page. Full discussion of how the mount contacts work may be found HERE and HERE.

On lenses lacking an aperture ring, the "A" contact should always have continuity to the mount face. For lenses with an aperture ring, this is only true when the ring is locked at the "A" position.* When you see F--- with a lens having contacts, the first thing to check is the aperture ring position followed by making sure that the lens is properly seated on the mount. If neither work a quick cleaning usually does the trick. I would avoid solvent-based cleaners since there is a risk of the liquid penetrating to places other than where it was applied. Before blaming the body, I would confirm that you get F--- with ALL of your lenses. You can test the "A" contact on the body with voltmeter. With the camera switched on there should be 10mV potential between the center of the "A" contact and mount face.


Steve

* On some lenses the "A" contact is a small pin that raises/lowers depending on ring position. On others the contacts always mate and state is determined by a small switch within the aperture ring mechanism.

Last edited by stevebrot; 03-23-2016 at 10:28 AM.
03-23-2016, 05:37 PM   #10
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QuoteOriginally posted by stevebrot Quote
On lenses lacking an aperture ring, the "A" contact should always have continuity to the mount face.
Actually the "A" contact on the body is slightly recessed below the surface of the mount so the "A" pin on the lens must be extended to make any contact. This is why you have to put a ball of foil or remove the mount a place a strip of foil over the "A" contact under the mount if you are trying to fool the camera into thinking M or K series lenses are "A" series.
03-23-2016, 05:44 PM   #11
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QuoteOriginally posted by Not a Number Quote
Actually the "A" contact on the body is slightly recessed below the surface of the mount so the "A" pin on the lens must be extended to make any contact. This is why you have to put a ball of foil or remove the mount a place a strip of foil over the "A" contact under the mount if you are trying to fool the camera into thinking M or K series lenses are "A" series.
I've not heard of "fooling" the camera into thinking an "A" rather than M" is mounted. So what would be the advantage, can the camera now set the F-stop?
03-23-2016, 05:55 PM   #12
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QuoteOriginally posted by gatorguy Quote
I've not heard of "fooling" the camera into thinking an "A" rather than M" is mounted. So what would be the advantage, can the camera now set the F-stop?
No, it may try to set the aperture stop, but with no guaranty of success. The aperture lever and diaphragm mechanism must be calibrated to that task and most standard K-mount lenses are not made that way.


Steve
03-23-2016, 05:57 PM   #13
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QuoteOriginally posted by Not a Number Quote
Actually the "A" contact on the body is slightly recessed below the surface of the mount so the "A" pin on the lens must be extended to make any contact.
Yes, this is immediately obvious on inspection. The lens-side implementations vary from a retractable pin to a spring-loaded pin or ball.


Steve
11-18-2016, 01:10 PM   #14
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So, just an update. I sent the camera for repair again, and it only took on the order of two weeks this time. Definitely an improvement on that front. The camera seems to work now.

The explanation of repairs is:
Main flex circuit and CPU repair. A complete repair and return all functions to factory specs. Auto focus test, check recalibration and realignment. Firmware download: corrections and adjustments; address values measured and adjusted. Complete cleaning (internal-external) and optical system.

How likely is it, do you think, that these repairs fixed the problem for good? I don't want the problem to recur, since the warranty runs out in February, and I'm sort of debating whether to sell it while it still works and buy a new body (being very clear about the prior problems, of course), or keep it and keep using it.
11-18-2016, 01:53 PM   #15
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QuoteOriginally posted by Outis Quote
So, just an update. I sent the camera for repair again, and it only took on the order of two weeks this time. Definitely an improvement on that front. The camera seems to work now.

The explanation of repairs is:
Main flex circuit and CPU repair. A complete repair and return all functions to factory specs. Auto focus test, check recalibration and realignment. Firmware download: corrections and adjustments; address values measured and adjusted. Complete cleaning (internal-external) and optical system.

How likely is it, do you think, that these repairs fixed the problem for good? I don't want the problem to recur, since the warranty runs out in February, and I'm sort of debating whether to sell it while it still works and buy a new body (being very clear about the prior problems, of course), or keep it and keep using it.
I think it is probably a luck (or lack of it) of the draw. I have the k-3 and I am not worrying about it. TBH, I would suggest you keep it instead since it is already calibrated to the spec and in all likelihood better than getting a new one IMO.
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