40D, 400mm 5.6 lenses and 1.4x converters...

Started Sep 12, 2007 | Discussions thread
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Keith Reeder Veteran Member • Posts: 3,725
40D, 400mm 5.6 lenses and 1.4x converters...

Hi all,

I use the Kenko Pro 300 1.4x on my 30D/100-400mm IS (pins taped) and the results are very good indeed - AF is fast and reliable (in decent light not that much different to the combo without the TC) and the images I get are very satisfying for my humble needs.

Sadly, with the 40D the TC is a non-starter: AF will not lock on to even well-lit, high contrast subjects - it just hunts back and forth with no hint that it will ever acquire focus.

I've tried every AF mode, CFn III (I think) and even taking the tape off (well, you never know) to no avail.

Without the TC and the 40D/100-400 combination is brilliant though, so I can live without the extra reach for now - it was always just a free bonus anyway.

Manual focus isn't really an option.

The question is: what are other folks' experience of the 40D and either of the Canon 400mm 5.6 lenses with a 1.4x TC?

I'm particularly interested to know if anyone has tried with the Canon TC, because if the solution is as simple as buying an on-brand TC, that's fine.

Any comments gladly received.

Romy? You out there?


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