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View Full Version : 100 - 400L IS USM AF HELP

BRASH
06-09-2007, 23:41
I have an EF 100 - 400L IS USM lens and 1.4 Mk II TC, which when fitted, knocks out the lenses auto focus. I knew this was the case when I bought them but I've heard there is a way to 'tape the contacts,' so the AF works. Does anybody know how this is done and which of the contacts need to be taped.
scraggs
07-09-2007, 05:28
Not sure if it's the same for the Canon but on the Kenko its the 3 farthest pins on the left.
Matt
07-09-2007, 05:35
Have a look at the contacts on your lens and TC.
You'll notice one of them has three extra contacts to the other.
The extra three are the ones to tape.

HTH
badgerbaiter
07-09-2007, 07:09
http://www.fencecheck.com/forums/index.php/topic,1183.0.html
BRASH
07-09-2007, 09:43
Perfect. Pins taped and AF working. Cheers for the tips.

:clap:
dsb
07-09-2007, 10:14
What is the reason behind stopping the auto focus? there must be a reason to it.
IanC_UK
07-09-2007, 18:42
What is the reason behind stopping the auto focus? there must be a reason to it.

With the TC fitted the max aperture of the lens drops to F8 non 1 series bodies will only AF to F5.6 the 1 series will AF to F8 its a limitation in the Bodies AF system.
Byker28i
07-09-2007, 19:20
Very useful having just obtained one of these lenses.

Strange one has to do this as Canon list the 1.4 and 2x convertors as compatible with this lens.