Originally posted by col.hutchins Hi all, I am new to this forum. I just picked up a 70-200 f2.8 Tamron. I'll eventually pick up a modern teleconverter that allows auto focus and transmits all the info from the lens to the camera.
But for the moment I happen to have a very old 2X APX Teleplus MC4 teleconverter kicking around so I threw that on to see how it works and surprisingly it is not too bad when used with the stop down metering green button like you would a manual vintage lens.
The one problem is I have no idea what aperture I am on. Can anyone help with this? I believe if I set the aperture when the lens is on without the teleconverter then turn the camera off and throw the converter and lens on, then turn it back on, the lens should have the same aperture as when I set it without the teleconverter?
Does anyone know if this is true, or if there is another sneak around? Surely someone out there has played around with old teleconverters on digital dslrs? Although I couldn't find anything on this out there in webland.
Any help would be greatly appreciated.
Cheers guys & girls.
I'm an enthusiastic user of 2x converters and I also have a Tamron 90-300mm with no aperture ring (amongst others), but I don't ever remember using a lens with no aperture ring with a 2x converter !
- goes away, grabs lens and converters then returns to computer -
Sorry, no results of any real help ... my Sigma EX 2x converter (with a/f and 7 contacts) simply won't fit on the Tamron lens. The Teleplus MC7 2x, with 6 contacts but m/f only, won't allow control of the aperture at all on my K-5 or my K-70. The Tamron SP 'F System' 2x with no contacts at all allows the K-5 (but not the K-70) to close the aperture with no indication of to what setting.
So, all in all, it would appear one needs a full-function 2x to get any control at all and then make sure it mechanically fits the lens before parting with money
Good luck