Originally Posted by WhyFi

Ah, okay. Keep in mind that the speed advantage isn't necessarily as big as you think it might be, 'specially compared to the wide end. You've got a two stop advantage in terms of aperture, but you can probably make up at least one stop or more via shutter speed (following the loose 1/equiv FL rule of thumb), even factoring in the IBIS, so it really comes back to whether or not the FoV is what you want given the subject. But yeah, no reason not to pocket the 50.