1.7x AF Converter won't work with lens

Rykoh · 12-29-2007, 11:24 PM

I was playing around with my Pentax-F 1.7x AF converter today and noticed that it will not move when mated with a Chinon K-mount 200mm 3.3 lens. This seems odd, since it works with all of my other lenses, including a 300mm 4.5, so I think it might just be that the 200mm has too low of contrast to work with it, even though it is relatively fast. Anyone noticed anything similar, or have any advice?

Thanks!

carpents · 12-30-2007, 06:22 AM

Just make sure that the contacts on the AF Teleconverter are touching the metal at the base of the 200. They need to be shorted out in order to work. You can also try wedging a thin piece of aluminum foil in between the lens and the TC just to make sure.

**Lowell Goudge** · 12-30-2007, 06:30 AM

I've never had a problem with any K mount lens f4.0 or faster, if, as others have suggested, it is not working due to the contacts, check the profile of thelens mount. it should be flat or recessed by no more than a few thousanths of an inch

12-29-2007, 11:24 PM	#1
Rykoh Veteran Member Join Date: Aug 2007 Location: Oregon, USA Posts: 318	1.7x AF Converter won't work with lens I was playing around with my Pentax-F 1.7x AF converter today and noticed that it will not move when mated with a Chinon K-mount 200mm 3.3 lens. This seems odd, since it works with all of my other lenses, including a 300mm 4.5, so I think it might just be that the 200mm has too low of contrast to work with it, even though it is relatively fast. Anyone noticed anything similar, or have any advice? Thanks!

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12-30-2007, 06:22 AM	#2
carpents Veteran Member Join Date: Sep 2006 Location: West Chester, PA Photos: Gallery \| Albums Posts: 1,420	Just make sure that the contacts on the AF Teleconverter are touching the metal at the base of the 200. They need to be shorted out in order to work. You can also try wedging a thin piece of aluminum foil in between the lens and the TC just to make sure.

12-30-2007, 06:30 AM	#3
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,891	I've never had a problem with any K mount lens f4.0 or faster, if, as others have suggested, it is not working due to the contacts, check the profile of thelens mount. it should be flat or recessed by no more than a few thousanths of an inch