Canon 200-400 f/4 reviewed by "Chasseur d'Images"

Started Jun 20, 2013 | Discussions thread
qianp2k Forum Pro • Posts: 10,350
Re: Canon 200-400 f/4 reviewed by "Chasseur d'Images"

Steve Balcombe wrote:

Oldvic wrote:

Thanks for quote. Just want to be clear that in above sentence - external 1.4x TC is better or worse than internal 1.4x TC? It doesn’t make sense if external TC actually is better.

That's what I can conclude from the graphs: at f/32, the external converter gives better results than the internal one; at other apertures, there's no difference.

At f/32 diffraction will totally dominate. Any difference which is not seen at larger apertures is just a blip - a statistical fluke or a bad measurement.

Agreed f/32 doesn't make sense to me that only happen if you shoot at high ISO such as 400 with very slow shutter such as 1/60.

Just as a general comment, it's hard to imagine that the internal TC would be any better than the 1.4x MkIII which is stunningly good on the MkII big whites. The point of the internal TC isn't better IQ, it's instant (and weatherproof) availability.

That part I actually hard to imagine other way around. I thought internal TC reduces gap, and internal TC lens elements probably are part of entire lens structure, that moves in and out dynamically. External TC is not part of original lens system in comparison and there is wider gap between two lens elements' groups.

If internal TC indeed has no difference to external TC, then I'd not spend extra $4K just for integrity if Canon offered two versions, one with TC and one without TC. Adding/removing TC is not that difficult and you can do pretty quickly.

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