Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-15-2010, 10:02 PM   #1
New Member




Join Date: Jan 2010
Location: Dubai
Posts: 1
teleconvertors

Hi,

I have a Sigma DC 75-300 f4/5.6 AF lens and I would like to know if there is a 1.4 or better teleconvertor that I can use with it and my K20D body and still retain auto focus.

01-15-2010, 10:11 PM   #2
Ole
Administrator
Ole's Avatar

Join Date: Sep 2006
Location: Copenhagen, Denmark
Photos: Gallery | Albums
Posts: 3,881
Tamron-F AF Teleconverter - 1.4X Pz-AF MC4

It is a very decent 1.4x converter, supports screw-drive autofocus.
01-16-2010, 03:59 AM   #3
Site Supporter
Rense's Avatar

Join Date: Dec 2008
Location: Zetten - The Netherlands
Photos: Gallery | Albums
Posts: 8,822
Hi John, welcome to these forums!
Probably you should have asked your question in the right section?
01-16-2010, 01:39 PM   #4
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,695
Welcome to the forum John - do be weary of where you post as it matters for archiving purposes.
The Tamron 1.4x TC is probably your best option, but will make AF function painstakingly slow and difficult in anything other then optimal lighting conditions, not to mention causing further image quality degradation to that of your existing consumer lens.

01-16-2010, 01:48 PM   #5
Inactive Account




Join Date: Mar 2007
Photos: Gallery
Posts: 3,675
QuoteOriginally posted by Rense Quote
Hi John, welcome to these forums!
Probably you should have asked your question in the right section?
moved to lens discussion forum...
01-16-2010, 02:21 PM   #6
Inactive Account




Join Date: Sep 2009
Location: West Sussex UK
Posts: 235
QuoteOriginally posted by Ole Quote
Tamron-F AF Teleconverter - 1.4X Pz-AF MC4

It is a very decent 1.4x converter, supports screw-drive autofocus.
I to have the Tammy and it "supports" both screwdriver and SDM/HSM focus. When I say "supports" I mean that it might focus one in four times on a reasonably bright stationery subject. Then there is the loss of IQ.

TCs are not great.
01-16-2010, 02:52 PM   #7
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
do you need AF supported

note that while a 1.4x TC will probably AF at the short end, it probably won't at the long end

at 300mm when you add the 1.4x you will have 450mm F8. Most AF only works to F6.7.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
k-mount, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Regarding optimal F Stop and Teleconvertors Tonto Pentax SLR Lens Discussion 5 05-15-2010 06:07 AM
Bigma Owners & Teleconvertors daacon Pentax SLR Lens Discussion 17 09-21-2007 06:22 PM



All times are GMT -7. The time now is 10:02 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top