Any news about the SDM TC?

vinzer · 02-19-2009, 04:37 PM

Just thought that maybe someone here might have heard of a couple more details regarding this one. Basically, I'm interested to know if it has the same AF magic as the previous Pentax F 1.7x TC, in that it makes non-AF lenses, well, AF. Being a fairly new Pentax user, I kinda missed the boat when those were still available, and while there's one seller on eBay who has that, it's sitting at a price that's above my credit limit *sigh*.

If this new TC can do the same feat, then I'd rather just buy it locally when it comes out, where I can pay for it in straight cash. I'm not sure how long it'll take for my card company to raise my credit limit.

mattdm · 02-19-2009, 05:59 PM

No news about anything. Be patient.

nixcamic · 02-19-2009, 09:34 PM

From the pictures of it would seem the glass element doesn't really have enough space to move the distance required to focus. My guess is that it's just a teleconverter with SDM electrical contacts. It could also have a SDM micromotor in it to power screwdrive lenses, but that wouldn't make sense.

Ishpuini · 02-20-2009, 01:09 AM

It looks very much like the Tamron 1.4x does. So it will probably be similar in functionality. It certainly will not replace the F1.7x, that was a unique case.

I'm hoping it won't simply be a rebranded Tamron 1.4x. That one does have the powerzoom contacts and as such allows the camera to recognise an SDM lens and provide power to the lens to use its SDM system. However, even if the lens tries to focus, the camera never achieves focus lock with a SDM lens on a powerzoom enable TC. I suppose there's more than just powerzoom contacts to it, and I'm hoping they get that sorted out. I'm hoping the postponing of the DA*60-250/4 might be related to its being tuned to the TC and vice versa... I have found that the FA*300/4.5 still has enough light to focus with the 1.4x so the DA*60-250 being a f/4 shouldn't be a problem at all. A well matched 1.4x TC would make the DA*60-250/4 a very desirable lens, possibly even drawing back part of the crowd that got another telezoom after giving up on the long wait...

Wim

*palmor* · 02-20-2009, 06:15 AM

Originally Posted by Ishpuini

However, even if the lens tries to focus, the camera never achieves focus lock with a SDM lens on a powerzoom enable TC.

Wim

That probably shouldn't be a blanket statement. There are people out there shooting their DA* with both that Tamy 1.4x and the Kenko 1.5x TCs without any problems. What does seem strange is that some people (like you) are having issues with SDM and some of the same exact TCs that do work for other people. There is someone else here that has the same problem you mentioned with the same exact TC I have.

I have the Kenko 1.5x TC and it works flawlessly with the DA*300. So much that if this new Pentax TC isn't weather sealed I probably won't buy it.

John

thibs · 02-20-2009, 06:44 AM

Originally Posted by palmor

That probably shouldn't be a blanket statement. There are people out there shooting their DA* with both that Tamy 1.4x and the Kenko 1.5x TCs without any problems. What does seem strange is that some people (like you) are having issues with SDM and some of the same exact TCs that do work for other people. There is someone else here that has the same problem you mentioned with the same exact TC I have.

I have the Kenko 1.5x TC and it works flawlessly with the DA*300. So much that if this new Pentax TC isn't weather sealed I probably won't buy it.

John

AFAIK TCs with SDM contacts do not work well. TCs without SDM contacts do work fine.

vinzer · 02-20-2009, 07:52 AM

Well, I'll just assume for now that it won't have the 1.7x magic, then. Thanks for the replies, guys. I hope there's more to it than just a plain-jane TC, though.

thibs · 02-20-2009, 11:26 AM

Originally Posted by vinzer

Well, I'll just assume for now that it won't have the 1.7x magic, then. Thanks for the replies, guys. I hope there's more to it than just a plain-jane TC, though.

Yes plain TC.
By the way, the 1.7x isn't called rear converter (Pentax usual terms for TCs) but AF adapter. The roadmap specificaly says "Rear converter".

*palmor* · 02-20-2009, 12:37 PM

Originally Posted by thibs

AFAIK TCs with SDM contacts do not work well. TCs without SDM contacts do work fine.

I have the Kenko with the SDM contacts (or power zoom contacts) and it works flawlessly with the SDM of my DA*300.

philbaum · 02-20-2009, 09:46 PM

Originally Posted by Ishpuini

I'm hoping it won't simply be a rebranded Tamron 1.4x. That one does have the powerzoom contacts and as such allows the camera to recognise an SDM lens and provide power to the lens to use its SDM system. However, even if the lens tries to focus, the camera never achieves focus lock with a SDM lens on a powerzoom enable TC.
Wim

I get consistent focus locks with the Tamron 1.4x and the DA300 F4 lens. It does need a bit more light than just the DA300 lens alone, though :-)

thibs · 02-21-2009, 05:27 AM

Originally Posted by palmor

I have the Kenko with the SDM contacts (or power zoom contacts) and it works flawlessly with the SDM of my DA*300.

Originally Posted by philbaum

I get consistent focus locks with the Tamron 1.4x and the DA300 F4 lens. It does need a bit more light than just the DA300 lens alone, though :-)

Very interesting. So there's something else at play then.

Ishpuini · 02-21-2009, 09:38 AM

Originally Posted by thibs

Very interesting. So there's something else at play then.

Indeed... I tried a copy of the DA*55 on my TC and I had the same problem again... I wonder... could it be the TC, or is my "early production" K20D at fault? Although my K10D had the same problem... Probably my Tamron TC then... I think I'll try out the new TC before buying it when it becomes available just to make sure...

Wim