Yes, one of the areas I liked so much about this Lens was the ability to set the Camera @ f/4, Zoom out to 400, engage the 1.4x Converter, immediately goes to 560 @ f/5.6, then Back Button Focus on the subject, and start to follow the Animal back towards yourself, once the Animal fills the frame at 560, flip the converter out, immediately back to 400 @ f/4, don't touch a thing and the Focus stays locked on, then Zoom all the way back to 200.
Didn't I read somewhere here on CR that this is exactly not what you are "supposed" to do with this lens? I will search for it later, but I remember that someone had been told by Canon (not sure if CPS or not) that you should not change the converter while in use. A CR member did then come back and say it had worked fine for him, but I do recall that this was something discussed about the lens.
It might be worth ringing CPS about just to check what they say.
I will try to find the canonrumors post on it tomorrow.
Truly amazing pictures as always, btw.
Wow, I have been away for a few weeks, work, lots to catch up on. Just a quick reply re-Precautions for using the Internal Extender. Before I pre-ordered this lens, I did a lot of research on it...and a special thanks to EMl58, for all the additional information...much appreciated!!
There is a section in the manual...pages 16-17, that discusses the use of the Internal Extender. It was also mentioned in an article from TDP...Canon EF 200-400mm f/4 L IS USM Extender 1.4x Lens Review
Excerpt for article
"Canon does not advise shifting the extender into place until IS turns off and all memory card writing ceases. The Canon rep I talked to strongly advised against doing this and suggested that a service visit may be required of a lens that has been used in this way. Apparently electronics are at the root of the potential problem."
Now the question is: does this apply to the 1DX?
BTW...awesome pictures everyone!!!
I guess I should explain, does this apply to the 1DX? In the manual it states, "The internal extender installed in this lens can only be used under certain conditions depending on the type of EOS camera used".