September 02, 2014, 06:55:02 AM

Author Topic: 600EX-RT AF Light Assist  (Read 4379 times)

JRS

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Re: 600EX-RT AF Light Assist
« Reply #15 on: September 26, 2013, 02:04:14 PM »
Yes, except the 15mm fisheye that is f/2.8.

I was thinking of the 8-15mm Fisheye zoom, sorry.  I'll post results...

Did you try with your 70-300L?
Canon 5D3 | 24-105L | 17-40L | 70-300L | 135L | TS-E 24L II | 50 1.4 | 15 2.8 Fisheye | 270EXII | 600EX-RT (x2) | ST-E3-RT

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Re: 600EX-RT AF Light Assist
« Reply #15 on: September 26, 2013, 02:04:14 PM »

neuroanatomist

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Re: 600EX-RT AF Light Assist
« Reply #16 on: September 26, 2013, 05:45:08 PM »
Did you try with your 70-300L?

Just now.  Turns out there's nothing wrong with your 600EX-RT (or at least if there is, the same thing is 'wrong' with the three of them that I have).

I tried again with the 24-70/2.8L II, and the center point gives the thin vertical AF assist.  The 70-300mm f/4-5.6L IS gives the full AF assist array even with the center point selected.

So...I tried it with a variety of lenses, and this is what I found with the center point selected (selecting a point away from the center column always gives the full AF assist array):

  • EF 16-35mm f/2.8L II - thin vertical AF assist line
  • EF 24-70mm f/2.8L II - thin vertical AF assist line
  • EF 28-300mm f/3.5-5.6L IS - full AF array
  • EF 70-200mm f/2.8L IS II - thin vertical AF assist line
  • EF 70-200mm f/2.8L IS II + 1.4xIII - full AF array
  • EF 70-200mm f/2.8L IS II + 2xIII - full AF array
  • EF 70-300mm f/4-5.6L IS - full AF array
  • EF 100-400mm f/4.5-5.6L IS - full AF array
  • EF 85mm f/1.2L II - thin vertical AF assist line
  • EF 100mm f/2.8L Macro IS - full AF array
  • EF 135mm f/2L - thin vertical AF assist line
  • EF 600mm f/4L IS II - full AF array (part of which is blocked by the lens ;) )

You found that your 50/1.4 gives the thin vertical line, whereas your 15mm f/2.8 fisheye and 24-105L give the full array, and likewise, my 100mm f/2.8L Macro also gives the full array, while other f/2.8 and faster lenses give the thin vertical line.

Taken together, that suggests that with the 5DIII or 1D X and the 600EX-RT flash, the determining factor is which AF 'group' the lens is in.  Only Group A lenses give the thin vertical AF assist line with the center point selected, whereas Group B and slower lenses give the full array (the 15/2.8 Fisheye is in Group B, the 100/2.8L IS and f/4 lenses are in Group C, etc.).
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privatebydesign

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Re: 600EX-RT AF Light Assist
« Reply #17 on: September 26, 2013, 06:34:28 PM »
Just for the fullness of the thread.

I get different light patterns on the 600EX-RT AF assist with center AF point only with my pre 2012 1Ds MkIII's too.
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JRS

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Re: 600EX-RT AF Light Assist
« Reply #18 on: September 26, 2013, 07:16:59 PM »
Just now.  Turns out there's nothing wrong with your 600EX-RT (or at least if there is, the same thing is 'wrong' with the three of them that I have).

I tried again with the 24-70/2.8L II, and the center point gives the thin vertical AF assist.  The 70-300mm f/4-5.6L IS gives the full AF assist array even with the center point selected.

So...I tried it with a variety of lenses, and this is what I found with the center point selected (selecting a point away from the center column always gives the full AF assist array):

  • EF 16-35mm f/2.8L II - thin vertical AF assist line
  • EF 24-70mm f/2.8L II - thin vertical AF assist line
  • EF 28-300mm f/3.5-5.6L IS - full AF array
  • EF 70-200mm f/2.8L IS II - thin vertical AF assist line
  • EF 70-200mm f/2.8L IS II + 1.4xIII - full AF array
  • EF 70-200mm f/2.8L IS II + 2xIII - full AF array
  • EF 70-300mm f/4-5.6L IS - full AF array
  • EF 100-400mm f/4.5-5.6L IS - full AF array
  • EF 85mm f/1.2L II - thin vertical AF assist line
  • EF 100mm f/2.8L Macro IS - full AF array
  • EF 135mm f/2L - thin vertical AF assist line
  • EF 600mm f/4L IS II - full AF array (part of which is blocked by the lens ;) )

You found that your 50/1.4 gives the thin vertical line, whereas your 15mm f/2.8 fisheye and 24-105L give the full array, and likewise, my 100mm f/2.8L Macro also gives the full array, while other f/2.8 and faster lenses give the thin vertical line.

Taken together, that suggests that with the 5DIII or 1D X and the 600EX-RT flash, the determining factor is which AF 'group' the lens is in.  Only Group A lenses give the thin vertical AF assist line with the center point selected, whereas Group B and slower lenses give the full array (the 15/2.8 Fisheye is in Group B, the 100/2.8L IS and f/4 lenses are in Group C, etc.).

Neuro,
Thank you for your time testing all those lenses!

Good to know that there's nothing wrong with my flash :)

And very interesting that only group A lens have the AF vertical beam, don't know why it is not on the manual.
Canon 5D3 | 24-105L | 17-40L | 70-300L | 135L | TS-E 24L II | 50 1.4 | 15 2.8 Fisheye | 270EXII | 600EX-RT (x2) | ST-E3-RT

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Re: 600EX-RT AF Light Assist
« Reply #18 on: September 26, 2013, 07:16:59 PM »