Luminous Landscape Forum

Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: NicholasDown on September 16, 2009, 09:29:47 am

Title: Effect of EF x2 Extender on Autofocus
Post by: NicholasDown on September 16, 2009, 09:29:47 am

This is probably covered somewhere else, but can't seem to find the solution.
I'm hiring a Canon 70-200mm L f4 to use on a Canon 5D mk 2. When I add a Canon x2 extender which I've also hired, I lose auto-focus. Have I missed something, or do I just accept the need for manual focus?

Title: Effect of EF x2 Extender on Autofocus
Post by: francois on September 16, 2009, 09:36:36 am

Quote from: NicholasDown

This is probably covered somewhere else, but can't seem to find the solution.
I'm hiring a Canon 70-200mm L f4 to use on a Canon 5D mk 2. When I add a Canon x2 extender which I've also hired, I lose auto-focus. Have I missed something, or do I just accept the need for manual focus?

Canon bodies (except EOS-1) can only autofocus with lenses that are f/5.6 or faster. Your 70-200 f/4 becomes a f/8 lens when you add the 2x extender. This is mentionned somewhere in the manual. If you had a EOS-1, autofocus would be possible but only with the center AF point.

Title: Effect of EF x2 Extender on Autofocus
Post by: Tim Gray on September 16, 2009, 09:48:27 am

There is a kludgy workaround by taping over a couple of contact pins that allow the camera to TRY to autofocus, but it's hit or miss.  

Google canon autofocus tape pins

Title: Effect of EF x2 Extender on Autofocus
Post by: francois on September 16, 2009, 10:31:01 am

Quote from: Tim Gray

There is a kludgy workaround by taping over a couple of contact pins that allow the camera to TRY to autofocus, but it's hit or miss.  

Google canon autofocus tape pins

Fred Miranda has an article: http://www.fredmiranda.com/TipsPage/ (http://www.fredmiranda.com/TipsPage/)

Title: Effect of EF x2 Extender on Autofocus
Post by: NicholasDown on September 16, 2009, 11:13:48 am

Thanks to all for the info on this. Now it rings a bell about being in the manual...somewhere.
I will stick to manual focus.