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06-29-2013, 05:48 AM - 1 Like   #1
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K30 random underexposure problem

Exposure sometimes is unpredictably way off.

For example, during testing with fully charged battery, exposure set to manual, fixed ISO, bracketing off, matrix metering and taking a picture of exactly the same scene: one image about 3 stops under exposed, one about 1 stop under and one that is spot on. Not quite random because the under exposure it is much more likely to happen with a single image and the first image of a sequence. It can nail 10 images and then mess up 3 or vice versa. The majority of shots are exposed correctly. This has happened with every lens I tried after it initially started. The shutter sounds normal but I haven't focused much on the sound.

Any ideas would be welcome. Mike

06-29-2013, 10:45 AM - 1 Like   #2
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Have you set exposure bracketing on?

Also check if you use spot metering.
06-30-2013, 12:24 AM - 1 Like   #3
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Yes sounds like spot metering is on
06-30-2013, 06:09 AM - 1 Like   #4
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It happens regardless of the metering mode and is extremely inconsistent. Even full manual (which is how I usually shoot), on a tripod pointed at a blank wall and it still happens. I am inclined to think something is sticking as it is more likely to happen at the beginning of a sequence of shots, although one will be dark every now and then regardless. EXIF data all shows the same settings as well but wildly different exposures. Sounds like a trip for service is in order.

06-30-2013, 07:18 AM - 1 Like   #5
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You sure it's not bracketing?
06-30-2013, 09:11 PM - 1 Like   #6
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QuoteOriginally posted by Anvh Quote
You sure it's not bracketing?
Yup. I'm sure. I've checked all those settings and as confirmation there isn't any consistent sequence to the underexposed shots.
07-01-2013, 02:08 AM - 1 Like   #7
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Just checking for the simple things first.
But i've no idea now.

Does it also do this indoor?
07-01-2013, 02:05 PM - 1 Like   #8
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i just have mine and this also happens to me, right now i will try to update the firmware to see if this correct the bug.

07-05-2013, 02:54 PM - 1 Like   #9
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I have the same problem. At first it was like 1 picture per 50-80, now almost every other picture is completely dark. It happens only with low light condition. I tried reload firmware, reset settings, set different setting and found no solution. Here's example of 2 pictures take within 10sec, with the same light and camera setting.
K-30 strange issue - a set on Flickr
Exifs show the same values for ISO, aperture and time.
07-05-2013, 11:58 PM - 1 Like   #10
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darker could be the aperture, does it happen with 1 lens?
07-06-2013, 01:47 AM - 1 Like   #11
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I have only one lens for Pentax and yes, it's matter of aperture. Yesterday, after hours of fiddling, I found that for some reason aperture closes fully, even if set for other value. E.g. I set aperture on 4f, and when shooting it closes barely on 4f, but suddenly it starts to close on 32f. Rest of parameters are still on values for 4f, hence the dark pictures. The same is when I play with DOF button. It close aperture for set value, but after 5-6 pushes it close completely. When I release DOF button, aperture remains close for 1-2 sec and then is sound like shutter release and aperture opens.
07-06-2013, 02:50 AM - 1 Like   #12
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Here's short video:

Last edited by malcallm; 07-26-2013 at 08:51 AM. Reason: new link
07-06-2013, 03:59 AM - 1 Like   #13
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Thats not good, not good at all.
Clean the contacts of the camera and lens mount if that does nothing then you need to contact Pentax...

You could try to install (new) firmware again, that will reset some settings and such but i won't hold yor hope up that that will make a differnce at all.
07-06-2013, 04:14 AM - 2 Likes   #14
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I have cleaned contacts, reinstalled firmware, did anything I could imagine, but I'm afraid it's some mechanical/electronic failure. Here's topic from 2011, where mobiuspizza had the same issue with his k-x.
https://www.pentaxforums.com/forums/general-technical-troubleshooting/142184-...-before-2.html
Today he replied, that it was aperture motor failure. Bad news, especially that Pentax has very poor service in Poland, and usually repair/replacement takes 2-3 months
07-06-2013, 08:13 AM - 1 Like   #15
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In that case put on your best german and contact Pentax Germany, their service are overall best good from what i hear.
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