Canon Teleconverters Question

[Shakarpix]

Hi All,
  I've been a lurking for a while and finally registered a few weeks ago. I love the site and Forum.

I had a question about Canon TC's. I was pretty sure that I read somewhere on the Forum where someone said that the version II TC's can be stacked directly on each other, but the newest, version III TC's can't. Is that true? What about stacking a version II to a version III?

Thanks!

[neuroanatomist]

Not sure about III + III, but I just stacked a 1.4x III behind a 2x II, and they were physically compatible.

[Random Orbits]

III + III does not stack, I just tried it.  The 1.4x III portion that you would put into the 2x III is too long.

[bkorcel]

You can stack a 2X II and 2X III but not two III's.  The IQ loss is significant.  Better than not getting the shot but from a practical standpoint you are better off just cropping using a 2XIII only.

I personally think most of the loss is due to the 2XII.

I've heard of people using two IIIs with an extension tube in between but again you wont get an infinity focus...only good for closer up work.  I haven't tried that but I will and see how it works out.

[Harv]

I was able to stack my two Mark II TCs okay but my two Mark III TCs do not stack.

[Mt Spokane Photography]

a 1.4X II will stack to a 2XII, the 1.4X must be on the camera side.  I don't know if any other combination works.
I have a Kenko 1.4X on order to try with my 5D MK III for focus at f/8, and I'll be seeing how it stacks.  I also got a older 2X TC, which is likely a Sigma or Kenko but branded Quantaray, its actually ok, but does not allow AF at f/8 with my bodies, they just can't find focus.

[Basti187]

a 1.4X II will stack to a 2XII, the 1.4X must be on the camera side.  I don't know if any other combination works.
I have a Kenko 1.4X on order to try with my 5D MK III for focus at f/8, and I'll be seeing how it stacks.  I also got a older 2X TC, which is likely a Sigma or Kenko but branded Quantaray, its actually ok, but does not allow AF at f/8 with my bodies, they just can't find focus.

which kenko 1.4x are you getting? I was thinking of ordering the Pro 300 1.4X DGX as I read somewhere it will focus at f/8 on the 5dm3

[stolpe]

which kenko 1.4x are you getting? I was thinking of ordering the Pro 300 1.4X DGX as I read somewhere it will focus at f/8 on the 5dm3

I think that only worked on a 1Dx, not on a 5D Mark III. Correct me if I'm wrong.

/ Stolpe

[jthomson]

which kenko 1.4x are you getting? I was thinking of ordering the Pro 300 1.4X DGX as I read somewhere it will focus at f/8 on the 5dm3

I think that only worked on a 1Dx, not on a 5D Mark III. Correct me if I'm wrong.

/ Stolpe

Art Morris reported that the Kenko worked at f8  with an 800mm f5.6L on a 1DX but not on a 5D3

http://www.birdphotographers.net/forums/showthread.php/102647-1DX-Canon-800mm-f-5-6L-IS-Kenko-Teleplus-PRO-300-DGX-1-4x-AF-Teleconverter

[Shakarpix]

Thanks for the answers everyone! I appreciate it!

[dariusz]

See quote from digital picture. The most interesting part for me is that AF is working at f8 on 5D Mark II body with  Kenko on 400mm 5.6 L lens

http://www.the-digital-picture.com/News/News-Post.aspx?News=3022

Autofocusing at f/8 with Select Third-Party Extenders
 Thursday, September 13, 2012
Many people were unhappy that the Canon EOS 1D X could not auotofocus at maximum apertures of f/8 like previous 1-series bodies. We received a few reports that the Canon EOS 1D X can autofocus at f/8 using the Kenko Teleplus PRO 300 DGX 1.4x AF Teleconverter (Aurthur Morris posted on the subject recently) and we decided to run a few small tests to confirm.
 
We tested a "blue dot" (current) version of the 1.4x Kenko Extender with the Canon EF 400mm f/5.6 L USM Lens using center focus and various camera bodies focused on static subjects. Here are our subjective results:
 
Autofocus Performance

Canon EOS 1D X: AF worked and was fast with almost no hunting. However, metering was consistently off by +1 stop.
Canon EOS 5D Mark III: AF worked and was fast with almost no hunting. Metering worked as expected.
Canon EOS 5D Mark II: AF worked and was reasonably fast with a little hunting. Metering worked as expected.
Canon EOS 7D: AF worked, but the camera had a hard time locking focus. Metering worked as expected.
Canon EOS Rebel T4i / 650D: AF worked with a little hunting. Metering worked as expected.
Please note that we did not test with moving subjects and did not test image quality; results may vary depending on your situation. Other third-party extenders may work similarly.
 
Update: The EOS 1D X was originally tested with version 1.0.2 firmware. I updated the firmware version 1.0.6 and retested. Performance remains as reported above. Also interesting is that all 1D X focus points remain active (though periphery AF point use results in more hunting).

Posted to: Canon News
DateTime: 9/13/2012 1:01:49 PM CT

[neuroanatomist]

FWIW, reportedly the Kenko Teleplus PRO 300 DGX 2x AF Teleconverter allows AF at f/8 on the 1D X using the 600/4 II lens (2 stops EC required), and reportedly also works for f/8 AF on the 5DIII.

Unfortunately, unlike the Kenko 1.4x, the optics of the Kenko 2x suck, meaning the resulting in-focus image turns out to be a soft pile of mushy, well, you get the idea. 

[bkorcel]

So I just tested the canon 2XIII stacked with the canon 1.4xIII using an extension tube in between on my 300mm 2.8L.  12mm tube did not offer enough clearance to stack them but was successful using the 25mm tube.  In camera AF did not work, manual focus worked, so did Live View AF.  However as expected it would not infinity focus.  I got maybe 25-30ft before reaching the stop.  for those interested in close up high magnification shots this may be an option while still using the canon high quality III extenders stacked.

You can stack a 2X II and 2X III but not two III's.  The IQ loss is significant.  Better than not getting the shot but from a practical standpoint you are better off just cropping using a 2XIII only.

I personally think most of the loss is due to the 2XII.

I've heard of people using two IIIs with an extension tube in between but again you wont get an infinity focus...only good for closer up work.  I haven't tried that but I will and see how it works out.