I initially thought "Every Frame Perfect" meant a strict avoidance of any jank or stutter in motion, which I'm fully on-board for but as a film, video and 3D technologist, you're spot on calling out motion blur and similar temporal artifacts. In motion, they not only look 'most correct' to the human visual system, they are the most interpretable.

Adding the correct blur to motion makes it appear clearer but seen as a still, it's obviously not clearer. The nuance is correct motion blur appears clearer while guaranteeing it's as clear as the human visual system can perceive moving details at that speed, so no perceptual detail is actually lost. It's a method that objectively improves perception which only works in motion. If frozen, the method breaks. Thus, evaluating motion blurred stills for clarity or interpretability is incorrect.

The rest of the article focuses on details of proper implementation while missing the opportunity to question whether some of these animations should exist at all. IMHO, motion can be a valuable affordance in limited doses but it's reached a point of overuse and, in some cases, outright abuse of the user's visual field and cognitive load. Designers (and their PMs) see it as a badge of 'Refined Modern UX' but it's devolved into a trendy gimmick aping good design without being good design.

I think you are taking it a step too far. First of all, unlike film, we are not recording reality in any way, every pixel that appears on screen is there because we put it there. I'd argue a closer parallel is a cartoon. And something like cartoon inbetweening is not an example of imperfect frames. These are in fact, perfect and even carefully crafted frames.

It's one thing if the frame halfway through an animation looks a bit "funny", but is still completely logically correct. It is another if the intermediate state of the animation legitimately doesn't make any sense and is just the result of not really caring about what actually goes on during the animation. In that case I'd almost rather just not have the animation at all, or just have a simpler one.

The final "zoom animation from Preview app" also illustrates the inverse. Every frame looks perfect in isolation, just like the author wants. It's only when you see it in motion that you notice the issue.

I like this comment. The idea that animations should be able to be picked apart frame by frame and always be coherent doesn't make much sense, because the user will never actually do that.

I do like the point the article makes about using ui fidelity as a proxy for software quality, and agree that they pointed out some bad animations. But, I think you hit the nail on the head .. frame by frame coherence isn't the best yardstick for measuring animation "goodness".

I think it’s pretty telling that with the YouTube example, I legitimately couldn’t figure out what he could have a problem with until he slowed it down. The overall effect worked and gave the impression that it was aiming for. The fact that you can get out your calipers and find flaws in a paused animation is not compelling in the least to me. I don’t think looking at your animations in slow motion is a bad exercise — it may reveal unintentional things — but I don’t buy that animations need to “make sense” when paused in the middle any more than a 250ms snippet of audio clipped out of the middle of a word needs to make sense.

What do you think the premise of the article is? The article is pretty narrowly speaking of "app" UI and your comment is a "well actually" that some videos intentionally introduce noise or temporary discomfort for an emotional or artistic effect. On the same basis, comments like yours would defend screen shake if it was added to desktop and mobile apps on every user input.