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11-18-2010, 05:57 PM   #1
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Why isn't this lens Auto Aperture?

The lens is this:


I bought it a few months ago and used it successfully on my K1000. More recently, I modified it to remove the 'Rikoh Pin'. Once again, it seemed to function fine on the K1000.

When I put it on my K-x, it is not recognized as an auto aperture lens. As far as I can tell, the aperture ring is fully locked in the 'A' position. Also, the diaphragm arm moves freely and rotates fully to a mechanical stop.

Either I'm not doing something correctly, or something is physically out of alignment with the lens. How is an "auto aperture" lens detected by the camera, anyway?

Thanks in advance for your consideration.

11-18-2010, 06:13 PM   #2
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Are you sure you removed a Ricoh pin? I can't tell from looking at your photo but when an A lens is on A, there is a pin that should protrude to make contact with one on the lens mount. That pin tells the camera you are using an A lens.

11-18-2010, 06:21 PM   #3
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QuoteOriginally posted by JeffJS Quote
when an A lens is on A, there is a pin that should protrude to make contact with one on the lens mount. That pin tells the camera you are using an A lens.
Ubuntu,

The pin Jeff mentioned is at 4:30 location in this photo (not at the arrow):



When the aperture ring is NOT at A, the pin is recessed below the surface. When the ring is at A, the pin raises up to make contact with its mate on the camera body. The difference in height is very noticeable.
11-18-2010, 06:29 PM   #4
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Thanks!

Apparently, I botched the job when I altered the lens. I also have a 50mm auto aperture lens and I did not detect any pin on that (most likely, this was because the ring wasn't in an 'A' position at the time. So, to eliminate any chance of a stuck lens, I removed both pins!

Crap. $12 down the tubes

11-18-2010, 06:32 PM   #5
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QuoteOriginally posted by Ubuntu Quote
Thanks!

Apparently, I botched the job when I altered the lens. I also have a 50mm auto aperture lens and I did not detect any pin on that (most likely, this was because the ring wasn't in an 'A' position at the time. So, to eliminate any chance of a stuck lens, I removed both pins!

Crap. $12 down the tubes
Just use it as an M lens (or put the A pin back in if you saved the parts)..

11-18-2010, 06:35 PM   #6
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Bummer!

For future reference, not all Ricoh pins are bad. The pin in the photo below is harmless. Its head is rounded so doesn't get stuck.

11-18-2010, 07:45 PM   #7
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QuoteOriginally posted by Ubuntu Quote
Thanks!

Apparently, I botched the job when I altered the lens. I also have a 50mm auto aperture lens and I did not detect any pin on that (most likely, this was because the ring wasn't in an 'A' position at the time. So, to eliminate any chance of a stuck lens, I removed both pins!

Crap. $12 down the tubes
Actually, this might be a pure ricoh R-K mount (rather than a hybrid pentax/ricoh mount). I don't see a contact pattern to the right of the orange dot (in the photo in the first post).

If so, there's no way for the body to know the aperture range of this lens, and it was never possible to use this lens as a Pentax KA lens.
11-18-2010, 08:11 PM   #8
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In the foreground on the left is the hole where the necessary pin was mistakenly removed.



I believe the one in the background is the hole that lines up with the autofocus screw and was properly removed.

11-18-2010, 08:17 PM   #9
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QuoteOriginally posted by Ubuntu Quote
In the foreground on the left is the hole where the necessary pin was mistakenly removed.



I believe the one in the background is the hole that lines up with the autofocus screw and was properly removed.
Yep..

11-18-2010, 08:17 PM   #10
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QuoteOriginally posted by JeffJS Quote
Just use it as an M lens (or put the A pin back in if you saved the parts)..

No, I didn't save the parts. But twelve bucks is not a big investment my any means.

Thanks, everyone, for the timely and useful responses I did learn something today!
11-19-2010, 07:38 AM   #11
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QuoteOriginally posted by Ubuntu Quote
No, I didn't save the parts. But twelve bucks is not a big investment my any means.

Thanks, everyone, for the timely and useful responses I did learn something today!
that's OK, you can get a spring loaded pin from a scrap lens, or just put a spring loaded contact used in electronics to connect grid mount and install it in the base where you took out the pin
11-19-2010, 08:32 AM   #12
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If it makes you feel any better you're not the first person here to remove pins first and ask questions later. Unfortunately, it seems people sometimes interpret "beware the Ricoh pin" to mean "remove any and all protrusions".
11-20-2010, 09:39 PM   #13
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For what it is worth and to be technically correct, your lens is still auto aperture, though you have removed its ability to support automatic aperture control by the body.


Steve


(Owns several "Auto" lenses that lack "A" contacts...)
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