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#1
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Flicker is worse when the screen occupies a greater fraction of your vision. This is simply because peripheral vision is more sensitive to movement (and hence flicker) than central vision. 60Hz may look OK when watching TV from a reasonable distance but it's horrible when close up to a computer monitor.
For interlaced pictures there is an additional 25Hz or 30Hz flicker which is hard to describe but very obvious on 625 or 525. When I was a kid, the 50Hz large area flicker and 25Hz interlace flicker didn't bother me at all. That's how it was and most of us in Europe were used to it. In my late 20s (c1985) I got a job where I was investigating flicker on displays so I had to train myself to see it. Ordinary TV looked flickery then. We had an experimental rig that could show pictures with various scan rates and 2:1 or 1:1 interlace. 50Hz without interlace was pleasant. 100Hz interlaced wasn't too bad but 100Hz without interlace was lovely. It was also at the limit of the kit we were using so picture quality suffered in other ways. When I left that job I gradually became less sensitive to flicker again. At the Broadcast Engineering Museum we have built an all-CRT gallery (control room in US parlance) so many of the monitors are inevitably in peripheral vision. They flicker horribly. |
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#2
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Very interesting your experience with it.
Funny... in the past, tech people worried about quality of movement/displacement of objects on display and choose/set 2ms or near it for CRT phosphours formula persistence. Times flies, and S/H (sample and hold) displays such as LCD and all variants (CCFL-backed, LED-backed etc) come in. The market flooded with these marvels but it seems only I are worrying about the horrible motion rendering of it (but all people loved the absence of flicker). No manufacturer are at least concerned with it at least in the beginning. Then: https://blurbusters.com/blur-busters...mple-and-hold/ I discovered that I'm not alone: the nature of these displays really havocs the manner that we perceive motion (blur), and then makers have spent some years in pursuit of things for mitigation it (such as flickering the back light). I prefer flicker. Less processing power needed for same motion perception (1000Hz capable video board? $$$$$). But is a headache for eg. typing a text for the Videokarma... this is the field where LCD reigns supreme due to S/H mode of working (and the individual addressable pixels). Just in case, I don't believe we see with a 1000Hz frame rate biologically speaking, but I imagine that the motion/scan rate interacting with our own "scan" (variable for the peripheral vision, as you said), so the 1000Hz is for nulling any interaction. Proof of it is the difficult to see ficker on an 120Hz CRT. Besides other motion issues as explained in the link. LATE EDIT: I'm maintaining some CRT monitors and the test UFO is very clear against regular LCD displays. Amazing to see. No blur in the UFO! Is possible to see it with full detail at scrolling, even at 60Hz frame rate. The CRT holds up. Only OLED with flickering can truly enters into this territory. EDIT 2: I have a LG OLED TV that strobes the entire display once. Is horrible. Is usable only with 120Hz sources. Is different than a CRT monitor, due to the manner that CRT flickers (following the scan, not entire display once), even close watching the CRT monitor and hence seeing with some peripheral vision. Is good to save some dinosaurs to see the "real" new tech and what are really capable. Naturally, for very slow movements, the S/H displays will not show artifacts. Conclusion is the big size of newer TV's imposes automatically the nned of consider the peripheral vision and a eye-friendly reduction of blur.
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So many projects, so little time... Last edited by Alex KL-1; 07-09-2025 at 07:02 AM. |
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