400mm L 5.6 and TC 1.4

Will I loose autofocus with the TC on the 400mm with a 30D slr?

Yes, you will loose AF. And the viewfinder will be terribly dark. Dark enough as it is at f5.6 IMO

Yes, AF is lost unless you cheat by inserting a Mk I extension tube or tape the approriate pins. The AF achieved by cheating works but only in good light with good contrast in the subject - even then it may hunt for focus.

I tried both methods and found that the EF 12mm Mk I extension tube worked better for me than taping the pins of the TC. But, of course, the focus range is limited to about 9.5 to 44 feet which is good for small bird photography.

Also by cheating in these ways, the actual focal length and aperture are not recorded in the EXIF data.

Check the TC FAQ at the top of this forum for additional info. https://photography-on-the.net/forum/showthre​ad.php?t=41922

There are some teleconverters that are "non-reporting" that will retain autofocus function on the 400 f/5.6L with a 20D/30D/300D/350D/400D camera. Tamron and Kenko are two companies that have something that will work, but they are not their most expensive TC's. In fact, they are they cheaper ones, but they work pretty well with the 400 f/5.6L. I was so impressed with the Kenko 1.5x (4 element) model, that I left it on almost an entire vacation last summer. Cost all of $86.

Here's a couple from that trip:

HTTP response: 404 | MIME changed to 'text/html' | Byte size: ZERO

HTTP response: 404 | MIME changed to 'text/html' | Byte size: ZERO

HTTP response: 404 | MIME changed to 'text/html' | Byte size: ZERO

There are ways around it, something to do with tape

if you use the canon TC there is the "tape trick" just run a search for it. also as mentioed above somewhere the cheaper Tamron and Kenko non-pro Tcs allow AF.

OK, here is a question. If you loose AF with the use of a TC on these faster long lenses, why not just buy the less expensive manual focus longer lenses? Or does that not come out cheaper?

superdiver wrote in post #3172975
OK, here is a question. If you loose AF with the use of a TC on these faster long lenses, why not just buy the less expensive manual focus longer lenses? Or does that not come out cheaper?

well if you end up been to long with the tc for a shot you can take it off and have AF very fast AF i might add .
Rob

Do you lose autofocus because it "can't" autofocus mechanically, or because it "won't" autofocus due to not enough light?

Mike

mikemdd wrote in post #3173136
Do you lose autofocus because it "can't" autofocus mechanically, or because it "won't" autofocus due to not enough light?

Mike

AS far as i know its the fact that other than the 1series camera's they are not made to AF below f5.6 i.e f8 f11.
Rob