"Eric" <[EMAIL PROTECTED]> wrote/replied to:
I currently have a 100-400L and a Canon 2x extender and was wondering if it was only canon extenders that you lost auto focus on, or all lenses slower than 2.8 regardless of the extender used.
For what its worth, I use this combo on an EOS 3
thanks
Eric
EOS 3 and 1V will focus up to f8, other EOS cameras lose autofocus at f5.6. Unfortunately, you will be at f11 at the long end, and almost there at the short end.
I also use the 2X with that lens and I don't mind manually focusing one bit. I would imagine focus would be quite slow even if it did work at the short end. The compactness and light weight of this combo more than makes up for lack of auto focus.
By the way, the shots I've made with this combo have been excellent. I have the latest model EF2X II.
3rd party extenders that don't report the aperture correctly will focus somewhat one some EOS cameras, but it's slow and cumbersome. I used to use the Kenko MC7 2X on my 75-300 and with EOS 10 I could auto focus in the lower half of the range at least. But it wasn't worth using, I just manually focused it. And the quality of it was so poor, it wasn't really an option for serious shooting.
Strangely, the MC7 did a 'decent' job with the 75-300, but I tested it on my 85/1.8 and it was crap. I guess extenders are designed for longer focal length lenses.
Jim Davis
I have the 1.4x and 2x (earlier versions) and the 100-400 with an EOS3; the 1.4x works well in AF mode on the 100-400 and also produces noticeably higher quality than the 2x.
As far as converter/lens combos, unless they are designed for one another, it's a bit of a crap shoot. Years ago I used to have a Nikon 180/2.8 with a Vivitar Macro Converter, which was the best lens/2x converter combo I have ever used; much better than using the Nikon 2x converter. On the other hand, a Nikon 400 with a Nikon 1.4x converter was the best lens/1.4x combination I have used. It's hard to predict; you just have to try things out.
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