[jval43]

Try birding at 500mm or more. Pixel soup (pun intended) vs crisp details from the R5 with 100-500, even at f7.1 or higher. No comparison.

Even at 105mm f4 the difference is night and day. Portrait mode is good enough for casual use, but the real thing still looks better.

[jorlow]

Sure, it's weaker in telephoto. (I rarely shoot beyond 85mm.) Fwiw I never use portrait mode -- too artificial. The main lens still gets pretty nice shallow DOF tho