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08-12-2016, 01:28 AM   #1
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Curious as to why the K20D does and the K-5 does not?

Having a K mount manual lens with a black anodised mount means some work on the mount or some conductive foil strategically placed to enable green button stop down metering on a K-5 (and others) but no problem on the K20D (and earlier?).
I have looked in previous threads and found the suggestion that having video on one of the later cameras might be the culprit.
Can anyone add to this or provide another reason?
Apologies if this has already been covered and I did not find it.

08-12-2016, 03:17 AM   #2
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You are actually right!
I thought that with all black anodised lenses you would need to use aluminium foil, not true!
My K10D works fine without it, all later no go, why?
we should have menu setting to go
around it

Last edited by BigMackCam; 08-12-2016 at 04:47 AM. Reason: Removed vulgarity.
08-12-2016, 04:43 AM   #3

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QuoteOriginally posted by i_trax Quote
we should have menu setting to go
around it
How exactly would this work?
08-12-2016, 08:20 AM   #4
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Had to dig deep into my pile of lenses to find the only black K mount lens. Green button stop down metering didn't work on either K20D or K5.

Stop Press: Gave the anodised aluminium a good clean and yes, green button stop down metering does work with K20D!

Last edited by beachboy2; 08-12-2016 at 08:38 AM. Reason: Correction
08-12-2016, 08:54 AM   #5
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QuoteOriginally posted by Skodadriver Quote
Curious as to why the K20D does and the K-5 does not?
Things change and even back in the day, there was variation between Pentax models in regards to non-conductive mounts.

08-12-2016, 08:58 AM   #6
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Just to muddy the waters a bit - I have a Vivitar (Cosina) 135/2.8 with the black anodized mount. Green button metering has always worked on my older bodies (*ist D and K10D). However focus confirmation has never worked with any of them. I haven't tried it on my K-5 yet.
08-12-2016, 12:44 PM   #7
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Behavior due to conductive or non-conductive mounts seems primarily linked to the body. Seems like nearly all bodies or at least with bodies with firmware released past a certain date need conductive mounts for the green button to work. My thought is the intention is to not actuate the stop down lever mechanism when no lens is mounted or when a screw-mount lens is installed.

When a non-conducting lens is mounted does the green button do nothing when pressed? Or does it meter through the lens and set the shutter speed without actuating the lever?
08-12-2016, 11:57 PM   #8
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QuoteOriginally posted by Giklab Quote
How exactly would this work?
A mechanical switch would be the way to go


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