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01-03-2012, 12:00 AM   #1

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SMC Pentax-F 1.7x AF Adapter Marketplace Listing

Item for Sale
SMC Pentax-F 1.7x AF Adapter

Asking Price

Item Location
Denver, CO (United States)

Item Description
SMC Pentax-F 1.7x AF adapter. Excellent condition, clean glass, works fine.

For those not familiar with this item, it is a very special and scarce 1.7x teleconverter that provides auto-focus capabilities to manual focus lenses. Basically what you do is focus the base lens on infinity or for closer subjects you set it to a quick "ballpark" focus and this adapter has its own moving element (using the normal AF drive mechanism) that locks in the focus. So for far off subjects it is just like using a real autofocus lens, and for closer subjects you just have to get the focus close enough so that the adapter can work its magic.

Some caveats for autofocus function: only K-mount lenses with bare metal mounts are supported, i.e. all of the Pentax pre-autofocus K-mount lenses, but also any third-party lens with bare metal on the mount -- some lenses with black painted or plastic mounts will not work (it must short the contacts). And so screw-mounts are not officially supported, even though you could mount them with an adapter ring. HOWEVER, all these other non-supported lenses can in-fact be made to work if you put some foil tape around their mount so they short the contacts. So you can actually use it with Takumars, etc (with genuine m42 Pentax adapter) with a little extra effort to fool it into thinking it is a bayonet mount. (I do find that using the m42 adapter on the TC seems less secure that using it on the body for some reason, so if you have a big heavy screw-mount telephoto you'd like to use, be careful if using it on a tripod -- it the m42 adapter pops out, lens or body could end up on the ground.)

And be aware that slow lenses won't work very well for autofocus (will hunt) on anything but bright sunny days because you lose some light just using the adapter. Which brings us to the usual limitations of any teleconverter: you lose a stop just using the thing, and in order to get reasonable sharpness you should stop down the base lens 1-2 stops (preferably 2) from its maximum aperture. 'A' lenses are fully supported so you can control aperture via the body. If you use a lens that already has autofocus, the focusing will still happen in the adapter and not in the lens -- you must manually set it to infinity or ballpark focus like any other lens you would use with it.

Comes with generic front and rear caps -- nothing else.

Please see details re: shipping, etc below pics.

Are you the original owner of the item being sold?

Are you selling or trading this item?

Item Condition (Key)

Shipping Destinations

Shipping Charge
$11 for USA (inquire for elsewhere)

Shipping Services
USPS Priority Mail + insurance

Accepted Payment Types

Return Policy & Additional Details
U.S. destinations preferred, but will ship most places. Shipping address MUST MATCH address on PayPal account. If you happen to be local to Denver, you may avoid shipping charge and pick up in-person and pay cash if you wish.

Please send me a private message if interested in the item!

01-03-2012, 12:44 AM   #2
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