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04-21-2011, 12:22 AM   #1
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645D color problem at 1600

I have had my 645D since Dec. , really great results, shooting P67 lenses, western sierra,sequoias in the snow etc..

I finally got a 645 lens, the 80-160, and i went to look at the first few frames and for the first time got a sensor/processor problem......

in the example you can see that half the frame is a different color and density from the other half (its exactly half, i measured)......the trouble is in the blue channel only , as you can see if you download the image to photoshop.

i havent got to the bottom of it yet , but i suspect iso 1600 (expanded iso per pentax) , and also the problem occurs in the first two frames only so i suspect that the sensor had not come up to correct operating temperature as the rest of the frames do not have the problem and i had just turned on the camera for the first time in that day.

so, any one else have color mismatches in one frame? at what iso? did you send your camera in?

Thanks,
David T.

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04-21-2011, 01:14 AM   #2
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Sorry to say,

but the camera needs a service.
The CCD readout A/Ds have to be recalibrated.

I do not have that problem (at the moment).
Don't know why they drift.

-Linus-
04-21-2011, 02:58 AM   #3
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As Linus suggested, You need recalibration. You can read little bit on this LL forum topic about "sensor split" - Yosemite Set (645D) starting with post of "mtomalty"
04-21-2011, 07:18 AM   #4
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David,

1/80 sec under fluorescent light is not the best condition to test this since the electric current alternates at 60 HZ. Try slower than 1/60 sec on a tripod.

- Hark


Last edited by harklee; 04-21-2011 at 08:32 AM.
04-21-2011, 08:26 AM   #5
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I am the person who posted the Yosemite set at Lula. My camera has this issue but I have not sent it in to pentax yet. I contacted support and they said it can be recalibrated but more and likely would need to be sent to japan.

I have held off on fixing this because I have just been way to busy with photo shoots. Once I get some downtime (next month or so) I will send mine in.

Give Pentax a call. They will take care of you!
04-21-2011, 02:44 PM   #6
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This started on mine today. It's very disconcerting! I also picked up my 645d last December. Today is my first day on a weeks vacation and I didn't bring a spare camera!
This appears on all the photos. I always shoot in raw, but I tried a jpeg and the same thing happens.
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04-21-2011, 07:03 PM   #7
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Thanks for all the replys. I have done some more testing and the problem is easily recreated. And really bad news for this camera system. My camera shoots just fine in daylight or shade . Its literally the mixed light of my example frame that is causing the camera to tweak exactly half the frame to another white balance or color density. The camera is set to tungsten WB per the ambient light , but the daylight balanced laptop is tweaking half the frame . So, I really need the camera to make one color choice per frame. You know , like the 1DS Mk3.........

As per Shuttershanes suggestion that i call support and they will help me right out. Maybe i have been calling the wrong guys, Pentax Professional Services in colorado. They were very nice and perhaps are marketing people? Certainly not knowledgable techs or problem solvers. Should i call support in Chandler Arizona perhaps? Anybody with experience?

04-21-2011, 07:32 PM   #8
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672:

I doubt if CRIS will be of much help, but it doesn't hurt to call. You might try Pentax Canada, they unlike Pentax USA, have kept their repair services and so are more likely to have people trained for the 645D. They seem less willing to help USA customers recently, but here's the number:
(905) 286-5585 (main office).
Ultimately, it appears the camera needs service, did PPS offer a loaner?

Last edited by Thomas; 04-21-2011 at 08:16 PM.
04-22-2011, 07:10 AM   #9
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teroll,

The issue you show is much different, I have seen something similar on my old Canon 5D when I had a bad Memory card. Try a different card, if it still happens after that then that camera needs to go in for repair!
04-22-2011, 08:19 AM   #10
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Thanks for the reply Shane. I have never seen anything like this before and I've owned a few digital cameras and digital backs. I tried another card; same thing happens. Attached is the last series of photos I took before the sensor issue (at least that's what I'm assuming) started; a panoramic of Turtles Head Point on Kalamalka Lake in British Columbia. I tried another series of photos right after I took these and the blue streak was on all of them.
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04-22-2011, 11:16 AM   #11
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QuoteOriginally posted by terroll Quote
Thanks for the reply Shane. I have never seen anything like this before and I've owned a few digital cameras and digital backs. I tried another card; same thing happens. Attached is the last series of photos I took before the sensor issue (at least that's what I'm assuming) started; a panoramic of Turtles Head Point on Kalamalka Lake in British Columbia. I tried another series of photos right after I took these and the blue streak was on all of them.
First off nice shot

If you tried a different card then I suspect either a major issue with the sensor, buffer or sd controller. That looks bad!

Also tried a different SD slot...if it still happens after that get on the phone with Pentax asap!
04-22-2011, 05:08 PM   #12
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Thanks Shane.

I've tried both slots, different cards and combinations; all the same. I'll be getting in touch with Pentax next week. This is a tough lesson to learn; not bringing a spare. I was going make a little money this trip by taking some portraits, one corporate and a couple personal, that were booked. I brought all my other gear; strobes, etc. Oh well.....
05-24-2011, 07:36 AM   #13
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Hi guys

Joined the group end of last year and bought a K5 ...and recently the 645D.

No regrets in buying both cameras, both a real pleasure to use. However for your information I just thought I would add that my 645D does sometimes exhibit 'sensor split' which was apparent just days after purchase.

I first noticed it when I did the old dust sensor test flash shooting a white card out of focus @f22 and 100, 200 ASA, only when 'auto contrast 'or 'auto colour correction' in Photoshop was implemented did the 50/50 split show, one side being darker than the other ...though strangely I could not re-create the split by this method no matter if the camera at personal settings or settings reset. Then shooting some 30sec. night scenes last month at 1600ASA I again noticed 2 frames exhibited 'sensor split' against the sky background ...but should add that the cloudy sky background was slightly affected by orange sodium vapour street lighting.
Since updating the latest firmware I have not yet seen 'sensor split' so far but this is probably due to lighter nights here so not really had the chance to fully test under similar lighting conditions until darker nights return late in summer.

I do have a question to ask you guys regarding pixel mapping in the 645D but will post my question later in a new thread..... for now the dog is giving me the paw, time for a walk I think!

Regards

Mike
05-24-2011, 08:30 AM   #14
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Oh God. I thought this was a K-5 thread!
05-24-2011, 01:08 PM   #15
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mikeyscope

i sent mine in for repair. will let you all know what happens.

672
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