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08-14-2007, 01:43 PM   #1
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Do A series lenses have electrical contacts?

I'm looking at buying a 50mm f1.7 lens (a series obviously), but i asked the seller to confirm the condition of the electrical contacts (i thought there were 6 to allow the M, Av, Sv, Tv, TAv, P mode communication between the lens and the camera on a k10d). He says there are no contacts as it is a manual lens. In which case how does the camera set the aperture? I'm confused. Looks like I'm not really getting the hang of the Pentax mount systems :P

08-14-2007, 02:32 PM   #2
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I have the A50/1.4. There is one gold coloured pin and one opaque white insulator.
08-14-2007, 03:50 PM   #3
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There's only 5 contacts on the kit lens, and 2 on my A lenses.

Why not ask him to take a pic of the contacts and e-mail it to you
08-14-2007, 05:06 PM   #4
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this is so confusing!i think it is maybe 6 contacts on the camera side of the mount.. well according to wikipedia, but when was that ever reliable? one person says 1, another 2. Maybe I'm not so daft to be confused! Anyway, you're right little laker I should just ask for pictures.

I'm still intrigued to know more though. We must have a know it all on this topic?

08-14-2007, 05:16 PM   #5
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The simplest way is to verify that there is an "A" on the aperture ring. Even a seller totally ignorant of cameras can verify the presence or absence of the first letter he learned in kindergarten.
08-14-2007, 05:38 PM   #6
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what if they don't know whats an aperture ring? =p
08-14-2007, 06:37 PM   #7
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QuoteOriginally posted by FotoPete Quote
what if they don't know whats an aperture ring? =p
Buy it from someone who does know.

Each lens has a different pattern of contacts and insulators to identify itself to the camera. There is an explanation of the codes either at robertstech.com or bdimitrov.com, maybe both.
08-14-2007, 06:37 PM   #8
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If they're too stupid to understand a description of where to look for the "A", they're too stupid to do business with.

08-14-2007, 07:08 PM   #9
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QuoteOriginally posted by Mike Cash Quote
If they're too stupid to understand a description of where to look for the "A", they're too stupid to do business with.
Not true, that's often where you get the real bargains.

pixelpruner, does he by any chance live close enough for you to visit and inspect the lens.

The A doesn't really effect the image quality or make the camera much easier to use, so I wouldn't worry about it.
However things like fungus do make a big difference, and there's no way that he'll know how to check for that
08-14-2007, 07:43 PM   #10
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I didn't say "too stupid to know what the A is for". I love doing business with folks that stupid. They are indeed the source of bargains. I was talking about being too stupid to understand instructions about where to look to see if there is an "A" or not. Anybody that stupid has their hands full just remembering to breath and we shouldn't burden them further.
08-14-2007, 07:48 PM   #11
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Fungus is indeed a good thing to be aware for when looking at old lenses but more importantly, make sure the aperture blades are free of oil and open and close...snappily..(if that makes sense. haha.)
08-14-2007, 10:04 PM   #12
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QuoteOriginally posted by pixelpruner Quote
I'm looking at buying a 50mm f1.7 lens (a series obviously), but i asked the seller to confirm the condition of the electrical contacts (i thought there were 6 to allow the M, Av, Sv, Tv, TAv, P mode communication between the lens and the camera on a k10d). He says there are no contacts as it is a manual lens. In which case how does the camera set the aperture? I'm confused. Looks like I'm not really getting the hang of the Pentax mount systems :P
The number of electrical contacs on an A lens depends on the largest and smallest aperture of the lens. The contacts just constitute a binary coding of that information. As others have pointed out, just look for the "A" on the aperture ring.
08-15-2007, 05:12 AM   #13
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Right, that clears up a lot! thankyou all very much. In summary, the number of contacts varies depending on the lens - I didnt realise this (doh!). The number of contacts I was looking for was the number on the camera mount not necessarily the lens (doh again!). And I will simply check there is an A setting on the aperature ring. sound.

Thanks again.

And yes, stupid people = bargain hopefully :P
08-15-2007, 05:29 AM   #14
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Have a look at this page:

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