I don't claim to be able to tell the precise frequency just by looking at it, but I can absolutely see the flicker even with a fairly new lamp. Actually 100Hz stands out quite a bit more as it's not what I'm used to. When I visited the UK I found the lower frequency to be quite prominently visible in all types of discharge lamps. After I'd been there a few days it was less noticeable but the first night it was like whoa, flickery! The brain is able to tune it out to some degree, but when it's suddenly a different frequency than you've seen your whole life it's very visible. Lighting is something that has been a strong interest of mine my whole life so lights are something I've always paid attention to wherever I am.
Oh I am sure that a small part of people are more susceptible to the frequency as others.
For instance with DLP projectors the images are seperated in different primary colors and projected sequentially over a mirror device and a rotating colorwheel.
Some people don't see it while others go crazy with headaches.
All I am saying is that with fluo which was developed before WW2 there were relatively little complaints, whole generations grew up with them in schools and workplaces.
It helps that the plasma and phosphors kind of buffer the lightstream so the flicker is medium to low compared to Leds that are notorioys for fast on/off response.
So yes best is to dim leds with current and not pwm also for emc purposes.
It's one thing to ask professional related questions in a forum, it's quite another to ask them at every turn, relying entirely on the forum in order to do one's job.
I agree. I initially thought that Treez was a beginner but reading previous posts from other users and seeing in his profile he is 39 that sheds a different light on the matter.