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10-04-2013, 08:28 AM   #1
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Sigma to PK woes

Hi all. I'm an oldster looking to get back into a long-neglected hobby. I bought a Pentax K-r and a collection of AF lenses, some of which work just fine and others don't. Basically, all I want to know is, will a SIGMA SA AF FIT 100-300MM AUTOFOCUS ZOOM LENS fit on to my K-r at all and is there an adapter that will allow me to use the Sigma lens on the Pentax body.
Things have certainly advanced since I last got involved with this pastime so any help will be greatly appreciated.

10-04-2013, 08:53 AM   #2
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Welcome to the forums! About that lens: sounds like it has Sigma's own SA mount, designed to work with their own DSLR's. The SA mount actually uses the same bayonet as Pentax, so it should fit on your camera just fine. However, the rest of the mount is a copy of Canon's EF mount, which is electronic. You won't be able to use the autofocus, and there's no way for your K-r to stop down the aperture. Also, the SA mount has a shorter registration distance, so the lens won't be able to focus as close, and it will be able to focus well past infinity.
10-05-2013, 03:16 AM   #3
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Welcome to PF and bonjour from France ... enjoy the forum and the K-r ... please post us an image or two soon ... Salut, J
10-06-2013, 10:14 AM   #4
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QuoteOriginally posted by Grumpylump Quote
Things have certainly advanced since I last got involved with this pastime
Welcome to the forum, I thought exactly the same when I went predominately digital from years of film.


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