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03-17-2011, 07:07 PM   #1
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How to tell if a lens will fit a K20d?

I realize there are similar postings, but is there a way that experienced Pentaxians can tell when they're out at the 2nd hand stores? (without actually attaching the lens) I saw a Sigma lens today but don't know if it will work on my K20d. I'm fearful of the Ricoh pin and aren't sure if other lens "lock on and stay on"
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03-17-2011, 09:15 PM   #2
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With third-party lenses, you actually have to look at the mount, as all the manufacturers are cross-platform. Look at the lens mount to verify that it's a k-mount lens.

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03-17-2011, 09:51 PM   #3
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For third party lenses having the mount designation stamped on the side, if the designation includes an “R”, (i.e. “P/K-A R-P/K”, “PK-A/R”, “KR”) – these lenses will have the Ricoh pin.
03-18-2011, 07:19 AM - 1 Like   #4
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Some KR lenses have a Ricoh 'button' not 'pin'. The button doesn't protrude and is no problem. More than a few threads here discuss the Ricoh problems and solutions.

Without carrying a camera around (WHAT?!?!? LEAVE HOME WITHOUT MY CAMERA?!?!?) there is an easy and inexpensive way to judge lens mounts. Buy a cheap Chinese PK macro tube set, usually about US$8 shipped. (At least, that's what I paid a couple months ago.) The set has lens and body mount sections, and extension sections. Screw the mount sections together and keep them in your pocket. As you fondle a candidate lens, see if it fits.

ATTN! LENS BUTCHERS: This hardware is also useful to find how to modify a non-PK lens to fit on a Pentax camera. Unscrew the mount sections, insert the candidate lens in the body mount piece, and see where obstructions occur. This shows you where and how to taper the lens bayonet flags to fit under the PK mount lugs. It's like an inside-the-camera view.

03-18-2011, 01:40 PM   #5
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QuoteOriginally posted by RioRico Quote
Now that's good advice.

There are even some folk around here who even take dremels to the inside of the cameras let alone lenses.

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