[davidmanze]

No worries. I do well believe that this is an excellent lens ... which is why I have a hard time to believe that it is inferior to the G2.

Just because of diffraction alone, f/4 should be better than f/6.3 on the G2 assuming that the lens is well centered.

 

These zoom lenses are darn good, yes, but at least I can see a difference in quality when it comes to the rendition of fine details within very white or very dark structures (like feathers). The word "micro-contrast" is a bit overused but it is exactly that (which is high resolution in conjunction with high contrast).

The sample images of the Sigma 150-600mm C are undoubtedly sharp but that micro-contrast is missing (at 50mp).

Sometimes there is a big difference between theory and practice?

 

   Tele-zooms are a prime example of that!

 

   I'm certain that the 50Mps sensor is for perfect situations that don't correlate with my tele-experiences!