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FORUMS Canon Cameras, Lenses & Accessories Canon EF and EF-S Lenses
Thread started 24 Feb 2012 (Friday) 15:28
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Auto focus with teleconverter.

 
blakeG!
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I'm about to pick up a 100-400 and would like to get a 2x teleconverter to use for longer shots. Do teleconverters support autofocus and IS? If so, which brands do? I have a 7D if that makes any difference.
Thanks in advance!

Feb 24, 2012 15:28

-Blake
EOS 7D
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Snydremark
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IS, yes; you'll lose AF with a 2x on the 100-400, as that will drop your max aperture to f/11.

I had ok results with the 2x MkIII TC + 100-400, when I was testing out the 2x with my 70-200; but the 'Pump' was manual focus only with it. So I couldn't justify keeping it when it didn't work for anything on the 70-200.

Feb 24, 2012 15:34

- Eric S.: My Birds/Wildlifeexternal link (7D MkII, 7D, 40D, Canon 10-22 f/3.5-4.5, Canon 24-105L f/4 IS, Canon 70-200L f/2.8 IS MkII, Canon 100-400L f/4.5-5.6 IS, Canon 100mm f/2.8 Macro, Tamron 18-270 DiII PZD, 580EX II)
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watt100
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blakeG! wrote in post #13960399external link
I'm about to pick up a 100-400 and would like to get a 2x teleconverter to use for longer shots. Do teleconverters support autofocus and IS? If so, which brands do? I have a 7D if that makes any difference.
Thanks in advance!


Do a search, the Kenko Pro 300 DGX 1.4x teleconverter works on the 100-400 with autofocus and IS

Feb 24, 2012 15:42



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Wallace ­ River
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You will lose autofocus on this lens with any Canon extender, on anything but a 1D camera. A 1.4 will make the f5.6 into f8 and a 2X will be f11. You lose one and two f-stops respectively with the TC's. There is a way to fool the camera and make it try to autofocus by putting scotch tape over certain electrical contacts (I tried it) but it's unreliable and still realllllly slllooowww to focus except in real bright sunlight. Not worth it.

Feb 24, 2012 15:44

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blakeG!
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So you lose autofocus with the 2x. if I were to get a 1.4 tele, I would keep autofocus and IS?

Feb 24, 2012 15:50

-Blake
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pol024
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on a 7d yes

Feb 24, 2012 15:52



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Snydremark
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blakeG! wrote in post #13960574external link
So you lose autofocus with the 2x. if I were to get a 1.4 tele, I would keep autofocus and IS?

Maybe. Some of the 1.4s won't report the focal length change to the camera and AF will remain on; however, it still may slow down and/or be inaccurate enough to not be worth it.

All you can do is try and see how you like the results.

[EDIT: PS; don't get the Canon 1.4. The Kenkos tend to give better results in that range of TC]

Feb 24, 2012 15:54

- Eric S.: My Birds/Wildlifeexternal link (7D MkII, 7D, 40D, Canon 10-22 f/3.5-4.5, Canon 24-105L f/4 IS, Canon 70-200L f/2.8 IS MkII, Canon 100-400L f/4.5-5.6 IS, Canon 100mm f/2.8 Macro, Tamron 18-270 DiII PZD, 580EX II)
"The easiest way to improve your photos is to adjust the loose nut between the shutter release and the ground."

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blakeG!
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Snydremark wrote in post #13960598external link
Maybe. Some of the 1.4s won't report the focal length change to the camera and AF will remain on; however, it still may slow down and/or be inaccurate enough to not be worth it.

All you can do is try and see how you like the results.

[EDIT: PS; don't get the Canon 1.4. The Kenkos tend to give better results in that range of TC]

I plan on getting a kenko. Along with kenko extension tubes for my macro work :)

Feb 24, 2012 16:12

-Blake
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Canon 100mm F 2.8 Macro, Canon 400mm 5.6L, Tokina 11-16mm 2.8, Canon 28-135,Canon 430exii

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fredrikb81
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Don't bother with the extender on a 100-400 lens unless you plan on using it with manual focus. You will only be disappointed if you expect ANY AF capabilities.

Feb 24, 2012 18:11 as a reply to blakeG!'s post 1 hour earlier.



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blakeG!
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fredrikb81 wrote in post #13961333external link
Don't bother with the extender on a 100-400 lens unless you plan on using it with manual focus. You will only be disappointed if you expect ANY AF capabilities.

I will mostly be using it for moon and bird shots. With birds that far away, I should be able to use live view to focus pretty spot on.

Feb 25, 2012 02:45

-Blake
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Canon 100mm F 2.8 Macro, Canon 400mm 5.6L, Tokina 11-16mm 2.8, Canon 28-135,Canon 430exii

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Invertalon
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When I used a 1.4x TC with the 400 f/5.6 when I had it (taped pins) AF was terrible. But it still was nice to have the reach, and just pre-set the focus via live-view... For birding and such.

Feb 25, 2012 10:12

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amfoto1
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Don't expect great image quality with a teleconverter on a zoom. With a few exceptions (such as the Canon 70-200/2.8 IS Mark II with the Canon 2X Mark III), teleconverters work best with prime lenses.

A 1.4X "costs" one stop of light and a 2X "costs" two stops. So an f5.6 lens with a 1.4X added "becomes" an f8 lens. And a 2X on the same lens makes it an f11 lens. Technically, Canon cameras other than the 1D series are not supposed to be able to auto focus with less than f5.6 lens. You might still be able to manually focus, but your viewfinder will be dimmer too.

There are some tricks to try to get the lens to try to auto focus with a teleconverter. Use a third party TC that doesn't "report" to the camera. With TCs that report, you can tape up a couple of the electronic contacts so the camera doesn't know it's there. There are illustrations how to do this here on POTN and elsewhere on the Internet. Do a search if interested. Either way, the EXIF will only show the lens, not the lens + TC focal length.

However, "tricking" the camera will give reduced AF performance. It will be slower and it will hunt more... might fail more in lower light or lower contrast situations.

And adding the optics of a TC always costs some image quality. Less with a weaker TC (1.4X) than with stronger ones (2X). It can be very little loss with more ideal lens/TC combos... or a lot with less ideal combinations. In general, the 100-400 is not a very good zoom to use with teleconverters. But some people make it work adequately for their purposes.

Have you considered simply getting a longer lens, instead? For example, the Sigma 150-500mm lens alone might serve better than a 100-400 with a 1.4X. The Sigma also costs about $500 less.

Feb 25, 2012 11:38

Alan Myers
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troutfisher
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Personally having tried the combination of a 7D+100/400+Kenko 1.4TC (with the pins taped ) in good light I would not bother just stick to the lens +camera.
The 7D +100/400 is quite croppable, one of the benefits of 18MP.
This is about 70 yards away from my house and while there is not much feather detail I would not expect it at that distance.

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BTW I tried it with the TC and had to MF hand holding so all the shots were OOF.

if you want to read up on pin taping this http://www.michaelfurt​man.com/taping_the_pin​s.htm (external link) gives lots of info.
Like amfoto1 says if you need longer than 400mm try a longer lens
Feb 25, 2012 11:52

Chris
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Fiddlefingers
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AF will work in LiveView with any combination of lens + extender e.g. 400mm f5.6 plus 2x extender. It's very slow, but useable for stationary or slow moving objects. Best to focus just past the subject as the af always seems to go from far focus to close and back again until it finds focus. Therefore, it takes much less time to lock on if you firstly focus just past the subject.

Feb 25, 2012 13:08

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blakeG!
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Thank you for all the input everyone. Greatly appreciated. I'm guessing a tele would have a lot better IQ with a prime. Such as the 400 5.6. Decisions decisions...

Feb 25, 2012 13:50

-Blake
EOS 7D
Canon 100mm F 2.8 Macro, Canon 400mm 5.6L, Tokina 11-16mm 2.8, Canon 28-135,Canon 430exii

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