As someone who takes photos as a hobby, I keep finding ways to improve, and watching videos about photography is a good way to do that. I certainly learned a lot this way. However, last night I have stumbled upon something I've never imagined, and it's disturbingly bad for photography learners, so I decided to share this here so that people who read this will take note.
At the first glance, the title is rather clickbaiting, which I usually don't have much problem because pretty much every big channel does that. This time though, they definitely piqued my curiostity. After watching for a bit, the video above struck me as a typical professionally filmed show, which is fine. However, it quickly moved to a VPN sponsor, which is already a warning sign.
The main problem began when the guy started explaining the f-numbers. He claimed that a lot of people overcomplicated the focal length, but here it's him who is overcomplicating the aperture scale while leaving out the most critical piece of information: the √2 number. Instead of saying each other number is double of another and confusing people even further, you could just use this system:
Base f-number: f/1
1*√2 = 1.4
1*√2*√2 = 2
1*√2*√2*√2 = 2.8
1*√2*√2*√2*√2 = 4
I didn't invent this. This has existed for decades and should be the gold standard when explaining f-numbers. For clearer technical terms, you can refer to this link.
The guy didn't explain the one/third f-numbers either, so you can extend the above formula further to get them (although it's faster to just memorize them):
2^(1/6) = 1.1
2^(2/6) = 1.2
2^(3/6) = 1.4
2^(4/6) = 1.6
2^(5/6) = 1.8
2^(6/6) = 2
2^(7/6) = 2.2
2^(8/6) = 2.5
2^(9/6) = 2.8
Now that we are done with f-number, let's move onto focal length. First off, the guy was mixing focal length with magnification. You don't really change magnification while zooming. If that was the case, then telephoto lenses would have been the best for macro, while in reality they are a poor choice for close-up photography (even kit lenses are much better at that). What changes when you zoom is the angle of view on the subject (which is often described in the lens' specs and most people just overlook that), and you get the same effect by moving back and forth. Zooming just makes it easier since it reduces the need of moving to get the desired field of view.
Later, the guy was trying to debunk the "myth" of changing focal length changes the perspective. The setup might seem convincing for newbies, and from the upvote ratio, I see a lot of gullible people right there. What he was doing is that he was mixing and swapping concepts to trick you into thinking he is right. Well, technically he was right about moving changes the perspective, but so do cropping and zooming. They are just different ways of changing the perspective. Zooming in just allows you to get the illusion of background moving closer to your subject without sacrificing the image quality. You can achieve the same effect by using a shorter focal length and cropping later, but you lose so much resolution that it's not worth it. Compressing/expanding with a telephoto/wide angle lens isn't a myth. It's just a way to change the perspective with maximum level of details made possible with the use of such lenses.
I stopped watching the video right after this part because at this point the guy was already full of shit. I advise you to stay away from them in case you stumble upon them on Youtube. There are lots of better channels to learn from. This channel does nothing but ruining your perception of photography in the long run.