April 27, 2015, 10:35:03 PM

Author Topic: 600EX-RT AF Light Assist  (Read 6327 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 | 24-70L II | 17-40L | 70-300L | 135L | TS-E 24L II | 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.
Too often we lose sight of the fact that photography is about capturing light, if we have the ability to take control of that light then we grow exponentially as photographers. More often than not the image is not about lens speed, sensor size, MP's or AF, it is about the light.

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 | 24-70L II | 17-40L | 70-300L | 135L | TS-E 24L II | 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 »