alt Hacker News> While people have an image frame rate of around 15-20 images per second to make moving pictures appear seamless,
This is just...wrong? Human vision is much fast and more sensitive than we give it credit for. e.g. Humans can discern PWM frequencies up to many thousands of Hz. https://www.youtube.com/watch?v=Sb_7uN7sfTw
Replies
NO YOU ARE!
> make moving pictures appear seamless
True enough.
NTSC is 30fps, while PAL is 25fps.
The overwhelming majority of people were happy enough to spend, what, billions on screens and displays capable of displaying motion picture in those formats.
That there is evidence that most(?) people are able to sense high frequency PWM signals doesn’t make the claim that 15 to 20 frames per second is sufficient to make moving pictures appear seamless.
I’ve walked in to rooms where the LED lighting looks fine to me, and the person I was with has stopped, said “nope” and turned around and walked out, because to them the PWM driver LED lighting makes the room look illuminated by night club strobe lighting.
That doesn’t invalidate my experience.
Badly phrased but not wrong, this is the minimum frame rate for humans to perceive motion as supposed to a slide show of images.
The maximum frame rate we can perceive is much higher, for regular video it's probably somewhere around 400-800.
The discussion on flicker fusion frequency (FFF) and human vs. canine perception is fascinating. When building systems that synchronize with human physiology, like the metabolic digital twins I'm currently developing, we often find that 'perceived' seamlessness is highly variable based on cognitive load and environmental light.
While 24-30fps might suffice for basic motion, the biological impact of refresh rates on eye strain (especially for neurodivergent users) is a real engineering challenge. This is why I've been pushing for WCAG 2.1 AAA standards in my latest project; it’s not just about 'seeing' the image, but about minimizing the neurological stress of the interaction itself.