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01-15-2011, 01:42 PM   #1
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zlorfik's Avatar

Join Date: Aug 2010
Location: Italy
Posts: 6
K20d strange behavior

Hello, I need some help to understand the behavior my k20d had a few days ago, because I couldn’t find out what happened.

I was in Rome and passed the whole morning as a tourist, taking photos with my pentax DA 18-250 on. I was on the dome of church of St. Peter and I wanted to take one last photo of the verylonglonglong Mercedes that could be seen below in front of a papal building .

So I shoot at it, but when I check the photo I find it over-exposed (it was in P program). Ok, I surely made a mistake, so I’m going to repeat the shot but... when I'm going to focus, the aperture value blinks, switches, between the real value “F5.6” and "F--", with a frequency of approximately two cycles per second (half a second F5.6, half a second F--, and so on). When it shows “F—“ (as the lens was in manual aperture - but it does not have the aperture ring!) "MF" is shown in the viewfinder, while when if shows the F-value, “MF” disappears. The focus screwdriver motor seems not working (however, I’m not quite sure, I was worried and paid no attention).

The wheels do not work, changing the exposure mode (i.e. to A or M) doesn’t help, replacing the battery doesn’t help, removing and reattaching the lens doesn’t help ... and photos taken are always far overexposed.

Unfortunately, I have no other lens with me to try, so I put the camera away, wait 10 min (switched off, with battery on), and then try again and... everything works fine!

Could it have been the cold weather?? But I didn’t even have frozen hands! Have you any idea?
Was it something wrong with the Pope?

PS In the afternoon I took more than 150 pictures (with frozen hands) and everything worked perfectly.
"Allow Aperture Ring" setting was ON. Electrical contacts were clean, the lens and the camera were perfectly mated (I removed and reattached the lens several times).
PS2 sorry for poor English

01-15-2011, 07:32 PM   #2
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For an unknown reason, it seems like your camera lost communication with the lens. Unfortunately, with electronic devices, you sometime get glitches like that. When something like that happens, I think the best course of action is to take the battery off for a short while and re-insert it. It kind of reset everything back to normal.

Hopefully, that glitch won't happen again.
01-16-2011, 01:53 AM   #3
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Join Date: Aug 2008
Location: Michigan, USA
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With a DA lens, allow Aperture Ring should have no affect what so ever. The only thing I can think of that would cause your problem is a failed contact of the A pin on the lens mount. Either in the lens itself or the camera mount. With an A (or FA) lens, this pin will move in and out by setting or removing from the A position on the aperture ring. Since your lens has no aperture ring however, the pin should always be Out to make contact.

There are probably 100 things, both electronic and mechanical, that can go wrong and I suppose cold wet conditions could affect things negatively.

Good luck with it and welcome to the forums. Looking forward to seeing some of those Touristy photos.

01-17-2011, 09:28 AM   #4
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philippe's Avatar

Join Date: Apr 2008
Location: Flanders Fields
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I had something similar with a Ltd lens, a screw driven DA too, mounted on a K20.
Rather by chance, I discovered that the switch for MF ->AFS->AFC, stood somewhere in between (I don't say this was the origin of your issue). Perhaps by accident, due to the heat of the fight, I must have touched it and it moved, who knows? Anyway, there was something 'not in order' and then a lot can go wrong.
Don't forget: any switch can be moved accidentally and stand in the middle of nowhere, so check, double check and check again...

BTW, that's why I like the new design of the mode knob of the K7/K5!

01-17-2011, 01:18 PM   #5
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Join Date: Aug 2010
Location: Italy
Posts: 6
Original Poster
Thanks everybody!

You all are right... who knows what was wrong!

Not the AF/MF switch... I checked it... I would be glad to discover a knob or lever moved by accident, though I believe it was not mechanical but electronic fault.
In fact, when the camera decided to resume its functionality, I hadn't done anything.

Anyway, it's still ok, so I hope it was really a glitch.

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