Light Meter Malfunction K10

Started Feb 16, 2012 | Discussions
hereford
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Light Meter Malfunction K10
Feb 16, 2012

Hi all,

I have a K-10D. Recently when shooting aperature priority in bright situations it over compensates, shoots at, say, 1/3200 and the resulting image is virtually all black (under-exposed to the max).

The opposite has also happened where shooting at f2.8 it will fire 1/640 (instead of, say, 1/3200) and over-expose.
Seems to work OK on Auto, which defeats the purpose of an SLR.

I have ownd the camera since new, 2008. Also have a K-5 so K-10 does not get overworked these days.
Any thoughts? Light meter? firmware? just old and stuffed?
Cheers, Hereford

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rogerstpierre
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Re: Light Meter Malfunction K10
In reply to hereford, Feb 16, 2012

Difficult to say without seeing the subject and metering mode. You might have been shooting a contrasted subject in Spot Mode, which will inevitably lead to over or under exposure if you don't pick an "average area" of the image for metering.

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Roger

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hereford
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Re: Light Meter Malfunction K10
In reply to rogerstpierre, Feb 16, 2012

Great minds think alike... I tried the three different metering modes, all with same result.
I have had the camera for nigh on 4 years, and this is a new behaviour.
Thanks for the input.

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DrewE
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Re: Light Meter Malfunction K10
In reply to hereford, Feb 16, 2012

Have you unintentionally activated the auto-bracketing feature? I've done that once or twice (or at least forgotten to turn it off), and been rather befuddled by the seemingly random exposures.
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Wallace Ross
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Re: Light Meter Malfunction K10
In reply to hereford, Feb 16, 2012

Is it doing this with all your lenses? Perhaps try mounting a different lens and see what happens, maybe the lens is reporting the wrong aperature to the camera.
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rogerstpierre
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Re: Light Meter Malfunction K10
In reply to hereford, Feb 17, 2012

Well in that case, if it were me and I've excluded "operator error"... I'd reset the camera by removing the battery for at least 30 sec, recharge fully.

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hereford
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Re: Light Meter Malfunction K10
In reply to rogerstpierre, Feb 17, 2012

No luck with that either, I'm afraid.
I'll try a few more tricks over the weekend and report back.
Thanks for your help.

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moji
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Re: Light Meter Malfunction K10
In reply to hereford, Feb 17, 2012

hereford wrote:

Seems to work OK on Auto, which defeats the purpose of an SLR.

Ken Rockwell calls that P=Professional mode and use it as default mode!
Have you tried Hyper program?

Good luck!

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Russell Evans
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Re: Light Meter Malfunction K10
In reply to hereford, Feb 17, 2012

hereford wrote:

Seems to work OK on Auto,

Auto removes the EV compensation setting from the exposure calculations, so I would be looking at the exif data in the photos for the EV compensation tag to see what was recorded.

If the camera has an incorrect setting of EV comp that can't be resolved, I would suggest a default reset of the camera, followed by a firmware upgrade. The firmware will upgrade (rewrite itself) to the camera over the same version, and in doing so, it might clear whatever the issue is by overwriting or clearing the incorrect data out of the memory.

Thank you
Russell

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hereford
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Re: Light Meter Malfunction K10
In reply to DrewE, Feb 19, 2012

DrewE wrote:

Have you unintentionally activated the auto-bracketing feature? I've done that once or twice (or at least forgotten to turn it off), and been rather befuddled by the seemingly random exposures.

Thanks Drew. The auto bracketing was on. I turned it off...no change.

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hereford
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Re: Light Meter Malfunction K10
In reply to Wallace Ross, Feb 19, 2012

Wallace Ross wrote:

Is it doing this with all your lenses? Perhaps try mounting a different lens and see what happens, maybe the lens is reporting the wrong aperature to the camera.
--
http://wkoopmans.ca/notebook/

Thanks Wallace. Have tried with variuos lenses...all the same.

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hereford
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Re: Light Meter Malfunction K10
In reply to moji, Feb 19, 2012

Thanks Moji,

Behaves better in P mode, but that maybe because I haven't been able to push it above 1/2500 in P Mode. Make the camera usable for all but fast shutter speed work.

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hereford
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Re: Light Meter Malfunction K10
In reply to Russell Evans, Feb 19, 2012

Thanks Russell.
I have done all that you have suggested. No change in behaviour.

I have posted some shots with Exif data that shows the top of the sensor exposes differently to the bottom when high speed is used.

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hereford
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Re: Light Meter Malfunction K10 - Maybe not metering
In reply to hereford, Feb 19, 2012

Thanks everyone for your input.

I have done all that has been suggested, plus taken heaps more photos. These below show the "in between" area of the total blackout and correct operation.

As you can see, the images darken from the top down (when in landscape). The portrait oriented image shows this well.
The malfunction occurs with images taken above about 1/2000
Perhaps it is a shutter problem?
Any thoughts appreciated.

Cheers
Hereford

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DrewE
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Re: Light Meter Malfunction K10 - Maybe not metering
In reply to hereford, Feb 19, 2012

Unfortunately, from these pictures, I think it is a shutter maladjustment or malfunction. I'm guessing that the leading curtain is sticking or hesitating a bit. It may or may not make economic sense to repair, given the value of a K10D these days, but it's worthwhile to at least get a quote.

The effect is very similar to that of using a (non-HSS) flash above the X sync speed of the camera, provided of course that the camera allows the flash to fire. Most (or all) Pentax DSLRs disable the flash trigger above the X sync speed; however, many older film bodies would not do so. I got at least a few half-frame flash shots with my K1000 because I failed to set the shutter speed properly for flash operation. (With the K1000, the shutter runs horizontally, so the frame gets divided by a vertical line rather than a horizontal one.)
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hereford
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Re: Light Meter Malfunction K10 - Maybe not metering
In reply to DrewE, Feb 19, 2012

Thanks Drew,

It wasn't until yesterday afternoon, with dozens more shots taken, that I managed to capture these few that really demstrate the problem. As soon as I saw them I also started to suspect a shutter sync problem instead of the light meter, a bit like your flash experience.

I think I'll just have the K10 on stand-by and use with slower speeds. I have a K5 that I use most of the time for work & play.
Thanks for your input,
Hereford

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rogerstpierre
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Re: Light Meter Malfunction K10 - Maybe not metering
In reply to hereford, Feb 19, 2012

Maybe give your K10D a good workout. You said it's been sitting for quite some time, and the shutter may stick a bit, and it could go away after several actuation to re-lubricate the parts. Just a theory.

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hereford
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Re: Light Meter Malfunction K10 - Maybe not metering
In reply to rogerstpierre, Mar 2, 2012

Thanks Roger,
I have fired off about 1500 frames... no real difference.

Interstingly the dark area is more when shooting portrait tilting right than it is tilted left. !?!?

Thanks for your imput. The K10 is now a back up to my K5, and will niot be used to shoot above 1/1600.
Cheers, Hereford.

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