DA 300 + TC

That was me Mike-P

It was when I was looking for a tamron that would work with SDM and I saw that on the SRS website they had the particular lettering that works, but having called them they confirmed that the stock they had was of the new version and that image was an old one.

Sorry Cedric, I guess you will have to continue your search.

Thanks Amin & Mike, I have e mailed Chris at SRS. I guess I am rather hopeful but from Mikes comment things are not looking great. Maybe I will get some camo kit and get closer he he.

Cedric

The PZ (sdm) contacts, the two golden ones in the mount must be working, the SDM signal goes over that.

The camera gets information from the lens, so the lens tells the camera that it has SDM, then your camera wouldn't use the screw-drive it normally use but use the SDM only.
If you put on SDM lens on your camera you of course want to use that instead of the screw and using both shouldn't be smart so it logical only the SDM works then.

I've been runing with the thought of breaking the contact that gives the info of the lens to the camera but you've the problem that the Camera doens't do anything since it needs to read it's an AF lens.
Blocking the info contact wouldn't work.

Meter the PZ contacts and let us know what they do.
Since it says it's a PZ TC it should work with SDM so really strange...

I'm not sure you are correct with this statement. I have tried the DA*300 on a Kenko 1.5x with no operational SDM contacts but the Camera still knew it was an SDM lens so would not focus using the screw drive

Hi Stefan, the two gold contacts inside the converter are fine. There is continuity from one side of the converter to the other. The screw drive from the camera also does not work through the converter so maybe the signal from the lens is working ok. This is a bit of a mystery.

Cedric

I have just spotted what may be an issue with the converter. Looking at the lens mounting flange with the lens release lever at the six o clock position the third connector pin is flush with the face of the flange. I am hoping this is a Eueka moment. Will now set too it with my toolkit.

Cedric

Well that didn`t take very long, I removed the lens mounting flange and the insulator block for the contacts. Now I don`t know if this is a manufacturing fault or a deliberate way of having the third connector in place but not actually in use for the version that I have. The end of the pin has a flattened profile unlike all of the others which are domed. This has the effect of reducing it`s height by about half a millimetre and therefore not making a connection to the lens. If anyone has this converter I would apreciate it if you would view the pin heights and let me know if the third pin from the release lever is lower than the others.

Thanks

Cedric

You might be right but it surly delivers delivers the needed power.

There is also a normall contact that reads out the lens information and in that is the info what the lens can do.
You've 3 different option and reactions.

1 - No info about AF readed/recieved by camera from the lens - Camera thinks it's on old lens without focus system so doesn't try to focus at all.

2 - camera gets info it's an normall AF lens - Camera use the screw drive to focus

3 - camera gets info it's an SDM lens - camera use the two golden contacts (old PZ contacs) to power and move the focus.

(it's a bit more complex then this but it's the general idea)

The camera will always meter the focus and you'll get focus conformation with all of them since the focus metering is done in camera with all lenses.

Here are the contacts of the K-F mount link
The K-AF mount has one extra contact for digital information link

Here is also from the K-A mount... don't know how usefull that is and if it is used by the K-AF2 crippled mount link

My curiosity was aroused by this thread. I dug out my Tamron 1.4x Pz-AF MC4 teleconvertor and fitted it to my 50-135 (the only lens I have with SDM). The autofocus worked fine.

Duncan

Had a reply from SRS and it seems, oddly that some of the older Kenko and Tamron work fine with SDM. Wierd!

Cedric

Would you be interested in selling it?

Well Cedric you have had me looking at my old Bower MC 2X Pz/AF and thats the same. Have to get my Avo 8 out of retirement!

Yup, that's the version I have and its the only one that consistantly works with SDM.

Do you know why, it doesn't seem different then other TC with PZ contacts.
Have you ever compared it with other TCs Mike, would be interested to know your findings.

Not sure Stefan, it just seems to work as long as you get this model. There is quite a long thread on Pentaxforums about Teleconverters and SDM, out of them all the Tamron is the only one that seems to work consistantly.

EDIT: LUCKY I NOTICED THAT SPELLING MISTAKE BEFORE MY 10 MINUTES EXPIRED