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Canon 70-200mm F/4L and Teleconverters?

simwra 12 64 England
21 Jan 2009 11:01PM
I've had a search and can't find an answer, is it true the using a 1.4x TC will cause that lens' AF not to work?

Coleslaw 16 13.4k 28 Wales
21 Jan 2009 11:03PM
It works on my 40d.
strawman 17 22.2k 16 United Kingdom
21 Jan 2009 11:03PM
To my knowledge it works. A friend has a 30D and uses a 1.4 xTC on his 70-200 F4 IS. I think f5.6 is the slowest lens most canons will AF with (except the 1 series)
simwra 12 64 England
21 Jan 2009 11:15PM
Phew, that's good to know. Thanks a million.
21 Jan 2009 11:41PM
A friend from mine have a 70-200 mm canon lens. We put my 2x converter on and the lens was still working with AF.

Overread 13 4.1k 19 England
21 Jan 2009 11:59PM
was that the f2.8 version or an f4?
the f2.8 will still AF with a 2*TC whilst the f4 should not auto focus with a canon 2*TC - a 3rd party or taped pins on a TC might trick the camera into allowing AF, but from a few reports pushing AF beyond f5.6 tends to give some very mixed results; though generally its for brighter conditions (which is about the only time you will get good results with a 2*TC on the zoom lens anyway)
22 Jan 2009 12:03AM
Upps, to late for me reading... it was a f2.8 and not a f4.



steve_p 16 1.2k England
22 Jan 2009 4:36PM
I have the Kenko 1.4 teleconverer the AF works fine with my 70-200 F4 non IS.
geoffash26 17 2.5k United Kingdom
22 Jan 2009 5:15PM
It may well still work but the speed at which it focuses will be slower and it may also hunt in low light or on low contrast subjects
simwra 12 64 England
22 Jan 2009 7:13PM
Geoff, I don't mind if it's not 100% but if it turns out i need that little extra reach then at least its an option Smile
chris.maddock 20 3.7k United Kingdom
22 Jan 2009 7:28PM
My 70-200/f4 focussed perfectly with a Canon 1.4x extender. It "may" have been a little slower than without the extender, but not such that I could tell any real difference.

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