auto focus issues

[urrybr]

Has canon fixed the auto focus issues with the 1.4x and 2.0x tele converters??

[cicopo]

Since you're question lacks a lot of needed information to fully understand it I'll assume you want to know whether you can use either TC and retain good AF charistics. The answer is that in order to retain GOOD AF you need a fast lens & a pro body but even then you may be limited. The AF systems used require enough light to pass through the lens & if used the TC to still be strong enough to accurately detect the distance between the camera & target. The design limits are well known if you do your homework & I doubt there will be any changes in the near future with the possible exception of a firmware upgrade that will allow the 5D3 to AF at f8. Based on how long it's taking for that firmware to be released it's not an easy task.

[urrybr]

My camera body is the 5D MkII.  When the telephoto (600mm) is placed on the camera, the af works.  However when I put the 1.4x multiplier on the af does not.  I have discovered a work around, though.  I put tape over three of the contacts of the multiplier.  Then af works, albeit not really well.

[Tim]

Hi Urrybr,

The opposite should occur with the regards to the auto focus.  It may depend on which version of the 600mm lens do you are using? 

[cicopo]

From what I've read the best compromise is to use just the single center AF point whether using taped pins or not but you're still at the mercy of getting enough light through the lens for the AF to try & adjust the lens to match the distance to the target.. 

[hsbn]

What is your 600mm Lens? It will not focus on your 5DMII camera if it is F8 or slower with the extender. It's not an issue.