Over the past week or so as I've watched this video being posted and shared with comments like "Zack nails it" or "Zack finally settles the crop debate"... etc. etc. I've been very tempted to post a rant here and there... not because the overriding message that APS-C sensors are very good or that the Fuji cameras are very good... the fact is they are very good and produce exceptional image quality. Part of what bothers me is the factually incorrect analysis and his generalized statement that the difference between APS-C and FF is "negligible" when the fact is that there is a measurable difference between the two. For a well lit scene with only a few stops of dynamic range an iPhone has excellent image quality, otherwise it kinda sucks. Zack's video is way oversimplified... it's a sliver of a conditionally true statement and therefore pretty much useless. The other part that bother's me is his use of extended comparison... by putting even larger and even smaller objects beside the two you are actually comparing makes them look relatively similar in size and we humans are generally bad at absolute comparisons... we are much better at relative comparisons so what we "see" is that the APS-C and FF look about the same when compared to the really big and the really small. But that is scientifically invalid method of analysis. The visual distortion does not change the fact that the FF sensor is 2.5X larger than the APS-C and has significant and measurable differences in a number of performance parameters. Sure, under certain conditions the differences may not be within the ability of a human being to see it or any particular person may not care... but so what, not seeing or not caring does not change the physics and the facts. But taking those specific cases and uses that as evidence to make a general conclusion is faulty logic. That might not be Zack's fault per se... he is not a physicist or sensor technology expert. On the other hand, the guy is making money off blogging, teaching, writing, and possibly from sponsorship by Fuji. He is purposely entering the "sensor size debate" with a "humorous and endearing sensor size doesn't matter" video in order to get people to watch his video... it's a tried and true trick of marketing... tell people what they want to hear and in a way they can relate to it and they will buy what you be selling... in droves. And what is Zack selling... video views, blog posts, teaching, and Fuji cameras. I'm not buying. Except that I did because I watched the video and wrote this post. Arghhhhh.