extenders (doubler for us old folks)

[MMStar]

I have a 5d Mark ll and am interested in an extender (doubler for us old folks) and is it true thatthere are compatability issues? There are only certain brands and / or  models that I can use w/ this camera?

[cicopo]

The most common name for them now seems to be Teleconverters (TC's). This is the best source of info I know about them.

http://photography-on-the.net/forum/showthread.php?t=457299

Make sure you understand the effect using a TC has on the AF system.

[ebiggs1]

My advice is avoid them but if you have to, the Canon 1.4 is the best. But you need to see the lens' it is compatible with and works best with.