1.6 crop IQ tests don't look as sharp compared to full frame, why?

ttbek wrote:

Myrgjorf wrote:

Pones wrote:

Hi Guys

I recently purchased a 200-400 2nd hand and was toying with the idea of getting a 7D mark ii as a trial to see if I achieved better results with crop camera and no extender as opposed to full frame 1Dx with extender. Also extra reach of 1.6 would be handy. 560mm FOV. v 640mm FOV. I would struggled on low light days I am sure with regard to noise. Shooting AFL Football mainly.

the 7Dii looks so bad here

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=764&Camera=963&Sample=0&FLI=5&API=1&LensComp=764&CameraComp=453&SampleComp=0&FLIComp=4&APIComp=0

It does seem like the 7Dii is sharper than the extender enguaged on full frame

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=764&Camera=453&Sample=0&FLI=5&API=1&LensComp=764&CameraComp=963&SampleComp=0&FLIComp=4&APIComp=0

Anyone have experience they arte willing to share? Thanks in advance!

The build-in x1.4 in the 200-400 is very good so I prefer 200-400 @400 + built-in x1.4 + 1DX mk ii over the 200-400 + 7D mk ii. Adding an external canon x1.4 mk iii takes an IQ hit so I prefer 200-400 @400 + build-in x1.4 + 7D mk ii over the 200-400 @ 400 + built-in x1.4 + external x1.4 mk ii + 1 DX mk ii.

I haven't done any scientific tests though, just informal experience.

Well... DXO does, don't know why no one wants to accept it even though it almost always lines up with real world results as well, which this is yet another case of.

They measure the PMP of the 200-400 with 1.4x on the 1DX II at 13 PMP, and of the 200-400 without the 1.4x engaged at 11 PMP on the 7DII.

Your second scenario they have not measured, but I'm not sure that the external one is that different of a hit than the internal one (e.g. the internal one brings the PMP down from 18 to 13 on the 1DX II).

Of course the adapters can impact other aberrations in different ways, whereas using the smaller sensor will do so as a predictable magnification.

If I can't bring both the 1DX mk ii and the 7D mk ii with the 200-400 I bring the 7D mk ii for birding in good light and the 1DX mk ii for all other situations. I have got many good shots with the 7D mk ii but the 1DX mk ii is better: better IQ, faster AF, more reliable AF. And faster. I am not much into sports so I can't comment on football.

For my usage colors and contrast are often more important than resolution. And I find that the external x1.4 impacts colors and contrast negatively. Thanks for the numbers though.