So I saw rd95 post this video this morning about questioning the practical differences between cheap and expensive photography lenses. Unsurprisingly, he couldn't tell the difference, and neither could the "pros" in their video. Having spent several years as professional product photographer using a wide variety of lenses, from cheap kits to primes, my experience doesn't necessarily match their conclusions. Granted, technical product photography is much closer to "shooting a focus chart" than shooting some art film, or a cinéma vérité documentary or especially your kid's birthday party, but when you need to get 30 megapixels of toothbrush every millimeter of lost focus is a reduction in final resolution and every chromatic aberration is going to take at least (if you're lucky) a few more minutes in post to fix, the differences in lenses become more apparent.
Like the guy near the end says, the quality of the lens only become apparent under the most extreme circumstances; when your aperture is wide open or completely stopped down will the differences focal quality and range, and color accuracy be most apparent. Furthermore, in a day and age where we like to apply chintzy Instagram filters on our pictures to give them some kind of historicity, shooting with anything more than the most basic lens is laughable. Also, traditional film is much less forgiving than digital since you have so much freedom in a digital post environment to change and fix things.
The idea that we can all sit here and see some sort of obvious difference between the lenses over a youtube video is rather silly; sure you can pretend that using a 4k camera and watching the results on a 1080p TV is somehow "exercising" the lens, but it's really not. 1080p is the equivalent of 2 megapixels, and 4k cameras shoot at a little over 8 megapixels, while a good medium format DLSR will shoot with 50 megapixels and large format film can be scanned at 100-200 megapixels. Truth be told, the differences are usually only obvious when seen under a loupe, and when shooting under extreme conditions or with technical limitations. What that means is, yes, you get diminishing returns for increasing investments in your glass, and for 99% of consumer applications, and even 95% of professional applications, low to mid grade lenses are more than adequate.
Ultimately, people like to compare brand names as a measure of their self-worth and it's fun to think about what you're capable of instead of what you're likely to actually do, and those are the people who are most irrationally draw to expensive lenses as a form of conspicuous consumption. The real secret here is to buy a good quality used lenses (from a reputable dealer, of course). Unlike camera body/sensor technology, lens technology has changed minimally over the years. You can get a much better bang for your buck from a place like keh.com than you ever will shopping new.
In conclusion, it's like putting two thousand dollars worth of racing tires on my Accord, driving down to the store and remarking "Gee, these fancy tires don't feel any different than my old Michelins!" when in reality, not only do you need to be on a track to see the difference, you also need a particular caliber of car, skill of driver, and maybe even a skid-pad and lateral-g accelerometer to fully see the difference.
I disagree with your conclusions.
If all you have is an Accord, and all you aspire to do is drive down to the store, old Michelins will do fine. The issue with the video is that Freddie Wong is arguing that the only driving IN THE WORLD is "Accords going to the store" because that's all he knows how to do. On the other hand, I ride one of these:
...and I can tell whether the rear tire is at 32 PSI or 35 PSI based on how it behaves in 5th gear at 70mph leaned over into a turn tight enough that I have to hug my toes to the engine case so they don't scrape the pavement. I'm not a race car driver either, but I know what tires do.
Freddie Wong's mentality is "I have a car therefore I am a race car driver." It's a common refrain amongst the Youtube Crew: "I have sixty million views, no one taught me how to do anything, therefore I'm a fuckin' genius." You then surround yourself with sycophants who will reinforce your genius because the guy who actually knows how to get a cool effect from racking focus into the sun on a Cooke prime? Yeah, he's the guy you yelled at for slowing you down because "it's only a Youtube video."
High quality tools differ from low quality tools by one important aspect: the good shit won't let you down at the edge of the envelope. A set of Primos will rack focus smoothly regardless of how shitty your follow focus is. They will not flare unless you really push them, and then when you push them the flare will be beautiful. Their chroma won't smear, everything will be orthogonal and they will be tack-sharp from edge to edge. Yes, a 50mm Zeiss at 1.8 in the middle of the day focused on infinity will look very similar to a 50mm Canon at 1.8 in the middle of the day. But smart people don't shoot like that. It looks boring as fuck. These are the things that aren't of concern if you're basically documenting The Cinnamon Challenge in your kitchen but if you actually want someone to pay you for your work you probably ought to be doing more than documenting what's there.
There are people who don't know what they're doing that do it all goddamn day. They have opinions, and you can listen to them. If your ultimate aspiration is a frame like this:
Then you can take the opinion of the guy who framed that. If you, say, aspire to something better...
...then you'd best assume there's more to learn.
After all, Freddie, if it really doesn't matter, why aren't you shooting zooms like you used to?