[COULDBE2]

I have searched around on this forum to find out if my Tamron 1.4 converter will work on one of my screw mount lens. In one tread it was stated that a auto converter wouldn't work with a manual lens. I did connect the two and nothing happen on my K20. No functions and the shutter wouldn't fire. I was trying to extent the focal range of several of my manual lens without an additional purchase. Just double checking the info I read.
Mike

[Adam]

It should work, but you need to set the 'allow aperture setting other than A' custom function in your camera's menu.

[COULDBE2]

Thanks for the reply, I will try again.
Mike

[mikeSF]

i am borrowing a Tamron F 1.4 TC and am using it exclusively with my M42 manual tele lenses. Yes, it works just fine if your aperture ring is enabled.

[Lowell Goudge]

the problem is that the term auto had different meanings in the past.

With M42 lenses, it meant the aperture automatically stopped down when pressing the shutter, but the lens was wide open for focusing.

With the origonal K mount, and the latest M42 mounts for the spotmatic F and ES II , auto also meant open aperture metering.

There are lots of teleconverters and extension tubes that are advertised as "Auto" that provide open aperture focusing and metering for these lenses.

with KA mount lenses, a new meaning of auto was added, this was the "A" position, for automatic aperture but this was different than just allowing open aperture metering and focusing, this allowed the camera body to control the aperture directly (not just open / closed but stop down to precise positions) and allowed shutter priority and hyper program modes on the pentax cameras.

now there is "auto" focus also.

[Marc Sabatella]

It's possibl that when someone said your auto tc "wouldn't work" with a manual lens, they meant, it wouldn't provide automation. That much is certainly true. But I've used auto tc's on manual lenses with no problems, and can't really imagine how one could possibly design a tc that *wouldn't* work with manual lenses (and yet somehow worked with other lenses).