Could I use a TC and get AF with the Sigma 70-200mm F2.8 EX DG OS HSM?


Snootchies

Link Posted 22/03/2013 - 09:37
Having just reserved myself a Sigma 70-200mm F2.8 EX DG OS HSM which I'm very much looking forward to using, I've just been curious about whether there are any 1.4x or 2x TCs out there I could use with it and retain AF. Sigma's own compatibility chart seems to suggest there is nothing in Sigmas own TC line-up which could work.

Thought I'd ask and see if anyone knows more here.
Bob

My website (Hadfield Photography)

Pentax Gallery Artist page:link

Flickr Photostream: link

Snootchies

Link Posted 22/03/2013 - 10:31
Big fat no then.

Fair enough, at least I know. Thanks Strumstrum.
Bob

My website (Hadfield Photography)

Pentax Gallery Artist page:link

Flickr Photostream: link

jeallen01

Link Posted 22/03/2013 - 12:20

AFAIK, this is only true for Sigma's own TCs- but that TCs from Kenko and so on WILL autofocus with the Sigma HSM zooms.

BTW, in my experience (and of others, I understand) 1.4x TCs work OK, but don't expect the 2.0x TC's to be very quick to autofocus with these lenses.

John
K-3 II, K-3 and a K-70 from SRS (having now relegated the K-30 with the Hacked K-50 f/w to being a backup body) , & some Sigma and Pentax lenses (and a lot of old 35mm gear!)

Snootchies

Link Posted 22/03/2013 - 13:05
Seriously? Kenko one's will be ok?
Bob

My website (Hadfield Photography)

Pentax Gallery Artist page:link

Flickr Photostream: link

timothyw

Link Posted 22/03/2013 - 13:17
Nope, only those with the 'pz' designation and the powerzoom electrical contacts (which the HSM focusing uses)

These tend to be a bit rare and highly prized as Pentax only made powerzoom lenses for a relatively brief time in the 90s.

Here's a mini-review someone has put up:
http://www.clubsnap.com/forums/showthread.php?p=6475663

You can see the electrical contacts required on the left hand side of this picture:
http://i53.tinypic.com/2it0j8l.jpg
they're the 2 golden pins sticking up, inside the main metal ring.

jeallen01

Link Posted 22/03/2013 - 18:34
timothyw wrote:
Nope, only those with the 'pz' designation and the powerzoom electrical contacts (which the HSM focusing uses)

These tend to be a bit rare and highly prized as Pentax only made powerzoom lenses for a relatively brief time in the 90s.

Here's a mini-review someone has put up:
http://www.clubsnap.com/forums/showthread.php?p=6475663

You can see the electrical contacts required on the left hand side of this picture:
http://i53.tinypic.com/2it0j8l.jpg
they're the 2 golden pins sticking up, inside the main metal ring.

I stand corrected because my Kenko 1.4x IS a "pz" version and I thought most of them are that too. BTW, I never knew what the "pz" designation meant until now, and how it came to be - thanks!

However, it should be noted that most of us with the 55-300 Pentax have found that this is one lens that the Kenko does not work with very well. OTOH, the Kenko does seem to work at least moderately well with the 18-135mm Pentax and the autofocus does work with that combination - so it's still a handy thing to take on holiday.

Also since I have older, non-HSM 700-200 F2.8 and 100-300 F4 Sigmas and the Sigma 1.4x TC, I have not tried the Kenko with those (or not to a very great extent anyway)
K-3 II, K-3 and a K-70 from SRS (having now relegated the K-30 with the Hacked K-50 f/w to being a backup body) , & some Sigma and Pentax lenses (and a lot of old 35mm gear!)

Algernon

Link Posted 22/03/2013 - 21:04
The Jessop or Teleplus 1.7x's have all the contacts and work
well with the Sigma 150-500mm, which is the only Sigma lens
I have. It also works brilliantly with the Pentax 55-300mm.

I also have the rare Tamron 1.4x which doesn't give very good images
with the Pentax 55-300mm but works with the DA*300mm f/4 and probably
the Sigma 150-500mm.

See this thread.

-
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Last Edited by Algernon on 22/03/2013 - 21:06

bhairavp

Link Posted 23/03/2013 - 14:09
The Pentax 1.7X AF Adapter will work as well.

Snootchies

Link Posted 23/03/2013 - 14:12
Thanks guys - food for thought!
Bob

My website (Hadfield Photography)

Pentax Gallery Artist page:link

Flickr Photostream: link

SteveEveritt

Link Posted 23/03/2013 - 20:19
Look out for a Kenko 1.5x SHQ it works a treat with HSM/SDM
My Flickr link

"Life is what happens to you while you're busy making other plans" (John Lennon)
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