October 26, 2014, 03:55:39 AM

Author Topic: 1Dx and f/8 AF: it works.  (Read 2216 times)

Childeric

  • Guest
1Dx and f/8 AF: it works.
« on: July 12, 2012, 11:03:18 AM »
I have just tried the following combination on my production 1Dx :

Canon EF 70-200 f/2,8 II IS + Canon extender x2 III + Kenko extender x1,4 pro 300.

With these attached, AF works well, just a bit slow, with the central sensor. But exposure is wrong, roughly 2 IL overexposed.

It also works with the Canon extender x2 II.
« Last Edit: July 12, 2012, 03:25:50 PM by Childeric »

canon rumors FORUM

1Dx and f/8 AF: it works.
« on: July 12, 2012, 11:03:18 AM »

Mt Spokane Photography

  • EF 50mm F 0.7 IS
  • *********
  • Posts: 8896
    • View Profile
Re: 1Dx and f/8 AF
« Reply #1 on: July 12, 2012, 11:35:30 AM »
Without taping the pins??

neuroanatomist

  • CR GEEK
  • ********
  • Posts: 14758
    • View Profile
Re: 1Dx and f/8 AF
« Reply #2 on: July 12, 2012, 12:22:28 PM »
Without taping the pins??

With the non-reporting Kenko behind the Canon 2x, that makes sense. The same Kenko 1.4x allows AF on f/4.x-5.6 zooms.
EOS 1D X, EOS M, and lots of lenses
______________________________
Flickr | TDP Profile/Gear List

Childeric

  • Guest
Re: 1Dx and f/8 AF
« Reply #3 on: July 12, 2012, 01:14:30 PM »
Yes, without taping the pins.

Childeric

  • Guest
Re: 1Dx and f/8 AF
« Reply #4 on: July 12, 2012, 03:23:04 PM »
AF also works on the same 1Dx with the same Kenko x1,4 attached to the 70-300 f4,5-5,6 DO, at all focal lenghts.

Same issue with exposure however.

Childeric

  • Guest
Re: 1Dx and f/8 AF: it works.
« Reply #5 on: July 12, 2012, 05:24:12 PM »
From what I collect from various forums, my version of the Kenko x1,4 is reporting. And by the way, aperture as shown on the 1Dx display is the right one (minimum is f/8). Therefore, I am puzzled why exposure is wrong by more than 2 IL. Anybody would have an explanation ?
« Last Edit: July 12, 2012, 05:59:38 PM by Childeric »

Childeric

  • Guest
Re: 1Dx and f/8 AF: it works.
« Reply #6 on: July 13, 2012, 05:25:37 PM »
After more testing, it seems that it is overexposed by 5/3 IL (1,67).

Even odder...

canon rumors FORUM

Re: 1Dx and f/8 AF: it works.
« Reply #6 on: July 13, 2012, 05:25:37 PM »

Mt Spokane Photography

  • EF 50mm F 0.7 IS
  • *********
  • Posts: 8896
    • View Profile
Re: 1Dx and f/8 AF: it works.
« Reply #7 on: July 13, 2012, 10:20:46 PM »
I tested my 5D MK III with 2 TC's, and it worked with a 70-200mm f/2.8 but slowly.  Other lenses ranged from not at all to unreliable AF.  I also found AF to be inaccurate.  The in focus light flashed and the shutter opened, but images had varying degrees of AF accuracy.
I decided it could not be trusted except on the 70-200mm f/2.8, and with 2 TC's stacked on it, IQ was far from what I'd want with a huge investment.
Also note that when you stack TC's, only the one closest to the camera reports, with Canon TC's, it reports the wrong aperture and focal lenght.
« Last Edit: July 13, 2012, 10:23:38 PM by Mt Spokane Photography »

canon rumors FORUM

Re: 1Dx and f/8 AF: it works.
« Reply #7 on: July 13, 2012, 10:20:46 PM »