1.4x TC and focus speed?

[sharky]

I'm currently shooting with a 10D plus 70-200 f4, and am thinking of getting a 1.4TC for an airshow in a couple of weeks. I remember reading somewhere that using the 1.4x on this lens will slow the focus speed, and as you can imagine that wouldn't be a good thing with a fast moving subject. So for those who have this combo, what have your experiences been re. focus speed?

[defordphoto]

It'll be nominal. If it's a bright day, you may not even notice.

[IainB]

In connection with the 1.4TC, I see B&H have both the Kenko and the Canon, but the prices are $100 apart. Which brand is preferable?

[CyberDyneSystems]

Why Canon of course ;)

Really though, the design and engineering of the optics for the Canon TC's is specific to certain Canon lenses,. and they will work better together as a matched design than using a 3rd parties TC would.

However, the extent to which this will effect your images is hard to quantify.

[IainB]

I thought as much! I am awaiting my 70-200 F4 L and from what is said about the 1.4x I am reaching for the plastic...
Thanks CyberdyneSystems.

[ijohnson]

I have the 1.4x with the 70-200 2.8l. I am not sure what the scientific test people say but I can't tell the difference. Optically it is VERY hard to tell the difference. Focus-wise it is equally as hard.

Don't worry about it.

I hear worse things about the 2x though, especially with the 70-200 f4.

[Persian-Rice]

I have my friends 70-200 f/2.8 on loan for the weekend. I just picked up my 1.4x.
I know the 1.4x is a popular item so look for a very detailed review in a few days.

Just for the time being, the focusing is not that differnt. I tried using a differnt focus point and it actually worked, but it hunts like a bitch, I dont plan on messing up his lens or my lens when I get reimbursed for it, so i wont use differnt points alot. I think this only applies to the 2.8 non IS though.