These are both consumer level lenses. I had heard quotes that the RF 16 mm "would end up in every photographers bag." At 165 g and $299, you can see the appeal. But, as I pointed out in the thread of what's missing in the RF lineup, looking at the MTF chart left me underwhelmed.

But, Bryan just posted his initial take on IQ, and it has me thinking about this lens again. What is surprising is that it is actually comparatively good at f/2.8-f/4. What is disappointing is that it never really improves by f/8. Quick examples, but compared to the RF 15-35 f/2.8 at f/2.8, the EF 16-35 f/4 (my current UWA) at f/4. But then looking at f/8.

Really good for $299 and 165 g. Perhaps good enough to be a lightweight alterative to the zooms which weigh in at 540 g to 840 g. I get the market, it is a near perfect vlogging lens. I do not vlog, use this focal length for landscapes, but I've never been disappointed with the IQ out of my EF 16-35 f/4 at f/4....

I am adding the RF 100-400 as a placeholder for now. I am seeing some people pick it up as well as a lightweight alternative and so far, seem to be liking it. I'll be curious how it tests.