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05-20-2008, 01:05 PM   #1
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Does Ricoh P Lens work in Av Mode on DSLR?

Assuming the annoying pin on a Ricoh P lens can be eliminated, will this lens function as a Pentax 'A' lens? I.e., would I be able to use all program modes on a K10D, or would I have to shoot in Manual mode with stop-down metering?

I've tried to find the answer on this and other forums, but haven't.

Thanks for the help, guys!

05-20-2008, 01:11 PM   #2
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Does your Ricoh lens come with an "A" on the aperture ring? If yes, then... yes?
05-20-2008, 01:18 PM   #3
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QuoteOriginally posted by ftpaddict Quote
Does your Ricoh lens come with an "A" on the aperture ring? If yes, then... yes?
It comes with a 'P' on the aperture ring so...who knows? That's why I'm asking.

And in case it's not clear, I don't actually have this lens in my hands, so I can't mount it and test. I know others on here have Ricoh P lenses, so hopefully they'll see this thread and let me know.
05-20-2008, 01:29 PM   #4
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QuoteOriginally posted by Miserere Quote
Assuming the annoying pin on a Ricoh P lens can be eliminated, will this lens function as a Pentax 'A' lens? I.e., would I be able to use all program modes on a K10D, or would I have to shoot in Manual mode with stop-down metering?

I've tried to find the answer on this and other forums, but haven't.

Thanks for the help, guys!
Miserere; No, it will only work i M-mode, since the contacts for the KA-mount are missing. At least they are missing on my RIKENON P 28mm F2.8 lens, only the
Ricoh pin is present, and yes it work on my K10D. But the lens is a good performer.

Regards,

Mike

05-20-2008, 01:56 PM   #5
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It's probably a good occasion to ask my retarded question:


What was the purpose of the bothersome pin on the Ricoh mount lenses?
05-20-2008, 03:56 PM   #6
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QuoteOriginally posted by ftpaddict Quote
It's probably a good occasion to ask my retarded question:


What was the purpose of the bothersome pin on the Ricoh mount lenses?
I've always thought it was simply to annoy Pentax users. But maybe Ricoh actually put it there for a practical reason.
05-21-2008, 10:13 AM   #7
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QuoteOriginally posted by ftpaddict Quote
It's probably a good occasion to ask my retarded question:


What was the purpose of the bothersome pin on the Ricoh mount lenses?
I think the pin is there for a reason, if you have a Ricoh camera it will work in the same manner as Pentax with the KA-mount. But Ricoh have there KP-mount?!
Since the Ricoh lenses have a "P" setting on the aperture ring.

Mike
05-21-2008, 11:02 AM   #8
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Ricoh 'P' pin function

Mechanically, the Ricoh camera only knows how far the aperture ring is set to stop down from fully open. (there is a lever that rotates between about 2 O'Clock and 5 O'Clock when looking at the open camera body. A matching stud on the lens rotates and pushes this along as the aperture ring is rotated.) The 'P' pin indicates electrically to the camera when the aperture ring is set to 'P' mode, not just another stop-click below minimum aperture. Then the camera can determine how far to partially close the aperture during exposure. KA mount of same era uses different electrical connections to indicate lens settings. Ricoh/Rikennon lenses, at least in my experience, used a green 'P' on the aperture ring to declare auto-setting position and didn't have the KA contacts and hence are fully manual on Pentax (camera doesn't know value of fully-opened aperture or how far it is set to close down). Some third-party lenses (maybe all not associated with an RK camera, I only had a few) had both the Ricoh and the KA indicators and used an "A" (if I recall it is red, but I don't have one handy to check right now) to declare the auto-setting position. On these "A" hybrids, you can remove the Ricoh pin and still use the lens in auto-aperture modes on the Pentax camera.

05-21-2008, 11:18 AM   #9
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Thank you for the insight, nanobaud!

On closer inspection of my Soligor 70-200, I found where the Ricoh pin used to be. It was shaven clear off.

My lens has a green "A", and "P/K-A R" written on the lens mount.
03-16-2009, 06:48 PM   #10
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P mode on Sears

I have a sears 135mm f2.8 lens which I removed the pin from and it works in Av mode. The aperture ring reads " (A)P" in green followed by the 22-2.8 and then KR.

It was funny as I didn't expect it to work as and "A" lens and didn't bother trying it for a few weeks until one days I just tried it and it worked. I'm new to DSLRs and photography but I enjoy the lens a lot, and think the pictures are great. Especially for 20$
03-16-2009, 07:11 PM   #11
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QuoteOriginally posted by sailhobie Quote
I have a sears 135mm f2.8 lens which I removed the pin from and it works in Av mode. The aperture ring reads " (A)P" in green followed by the 22-2.8 and then KR.

It was funny as I didn't expect it to work as and "A" lens and didn't bother trying it for a few weeks until one days I just tried it and it worked. I'm new to DSLRs and photography but I enjoy the lens a lot, and think the pictures are great. Especially for 20$
He he... Funny. I was given the same sears 135 2.8 about four months ago. You just pointed out to me that it will work in (A)P mode! I'll have to use it a bit more now. Thanks!
03-16-2009, 07:17 PM   #12
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Note that there is more than one implementation of the Ricoh P mount. While Rikenon P lenses lack the contacts for Pentax-A compatibility, some third-party lenses featured a mount with both a Ricoh pin and Pentax A contacts. Those lenses should function properly as an "A"-type lens once the Ricoh pin is dealt with. I think that ftpaddict's lens with the "P/K-A R" designation probably falls into that category.

Steve

Last edited by stevebrot; 03-16-2009 at 07:26 PM.
03-16-2009, 07:45 PM   #13
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I have a "P" mount Ricoh 50mm F2, but it is the same as an "M" lens on my Pentax....No auto aperture control..
03-16-2009, 08:04 PM   #14
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I still think you could probably trick the camera into thinking it's an A-lens, but drilling grooves in the mount and using epoxy or something. I've never tried though.
03-16-2009, 09:55 PM   #15
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QuoteOriginally posted by Hapo Quote
I still think you could probably trick the camera into thinking it's an A-lens, but drilling grooves in the mount and using epoxy or something. I've never tried though.
And then there is the issue of the "A" pin itself! It is only "there" when the ring is in the "A" position.

Steve
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