K-r exposure problem


Pikaholic

Link Posted 12/02/2018 - 18:19
My K-r is producing very underexposed (black) images. Out of the 50 or so test shots I've taken, about seven have a very faint image. When I switch on the bright/dark setting, in both review and playback, this shows that the basic features of all the images are recorded to a limited extent. All the images were taken in program mode and some of the exif files/properties show aperture/time/ISO settings which could have been suitable for the subject. I have tried a variety of possibly camera settings, SD card re-format, reset and a manual lens to exclude lens coupling. I am now wondering if it is a software problem. I did let the battery drain to exhaustion and maybe that corrupted the software.
Any similar experience or ideas will be most welcome.
Thanks Bob
Old hand, slow fingers.

spinno

Link Posted 12/02/2018 - 19:01
hopefully it's not the aperture block failure of the K30/K50.
David

Pikaholic

Link Posted 13/02/2018 - 20:19
Thanks for that lead David, as I wasn't aware of the aperture block issue. I have looked up the thread about the K30/K50 and it mirrors my experience very well. My K-r precedes the K-30 by a couple of years so it's disgraceful that Pentax allowed it to affect so many models. I have tried some of the suggestions and some of them work. Setting an aperture of f32 worked and so did using an old manual lens. I think my results confirm that it is the dreaded aperture block and I shall have to consult a repairer. It's obvious from the posts that contacting Pentax is useless, which is very disappointing and undermines my confidence in the current Pentax brand.
I may add to the other thread as well as this one if I make some progress.

Kind regards, Bob
Old hand, slow fingers.

richandfleur

Link Posted 14/02/2018 - 00:21
Yes a good test is to use a manual lens, set to a fixed aperture, and see if that produces consistent results (as in confirm the camera is metering correctly).

Pikaholic

Link Posted 14/02/2018 - 17:34
Thank you Richard, from reading the other thread I know you are an expert on this subject.
I don't normally use manual mode so I'm having to read the manual to get consistent results. I'm working on it.

Bob
Old hand, slow fingers.

richandfleur

Link Posted 14/02/2018 - 19:00
Pikaholic wrote:
Thank you Richard, from reading the other thread I know you are an expert on this subject.

Wouldn't go that far, but yeah, it happened to my K-30

Haven't heard of it on a K-r though, so I guess I was wanting to diagnose it a bit more, in case it's a metering mode, or a lens specific issue.

Good luck!

Pikaholic

Link Posted 24/02/2018 - 16:38
I was pretty sure it is the aperture block problem, so I took it to a repairer in Bristol. I explained the fix that was well detailed on a YouTube video that had proved successful but he didn't buy that and wanted to send it to Pentax. I now have to bite the bullet and do the job myself. First I have to find out more about the filing operation. Is it to reduce the length of the magnet or just to clean the ends to improve contact. The video shows the ends finely polished so my guess is the latter purpose. I will let you know how I get on.

Bob
Old hand, slow fingers.
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