It's time for 29/30fps to die the death it has long deserved

On 30/05/2014 17:26, Sandman wrote:
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It is, there are gross differences in the sensitivity.

E.g.

http://webvision.med.utah.edu/imageswv/KallTemp7.jpg

from:


http://webvision.med.utah.edu/book/part-viii-gabac-receptors/temporal-resolution/

 

The unit, not the man, is fairly recent.

The unit was proposed in 1930 by the IEC, but it did not become standard
until 1960 when it was adopted as an SI unit by the CGPM.

Practically all textbooks and technical journals published before
1960 used c/s or cycles per second instead of Hz or hertz. Most
changed during the 1960s, although I wouldn't be too surprised to see
the old style in something printed as late as the 1970s.

(Nowadays it marks someone as very old fashioned in the same way
that using "mikey mike" for micro-microfarad or using mho instead
of siemens do.)

Sure they can. A cycle length of one millisecond is the same thing
as a cycle rate of one kilohertz which in turn is the same thing
as a rate of 360 000 degrees per second, or two thousand pi radians
per second or 60 000 revolutions per minute. You can express it any
way that suits your purpose. It might sound strange to say that
your record player spins at .55 Hz or has a cycle length of 1.8
seconds, but they can be perfectly sensible ways of putting it
in some contexts.

Peter.

 

On 30/05/2014 21:55, Alan Browne wrote:
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The other characteristic of CRT displays was the phosphor persistence,
and a long-persistence phosphor would reduce flicker. The persistence
could be chosen to match the application.

Agreed on update rate. I would have thought that the problem with some
modern vision systems was the lag caused by digital processing - that's
certainly been one objection to electronic viewfinders. I've recently
moved to a camera with an EVF, but not yet needed to take any action
photos. Too early for me to make a judgement.

 

No, I think 1850 is "relatively recent", and not "recent" when refering to the history of electricity and its units.

which went through to the sixties.

yep sorry but you should also have known

 

Uh, that chart actually confirms what I wrote. It shows where the test
subjects could see flicker in different light situations. As you can see,
no one could detect flicker over 50Hz at any light situation, and since all
CRT flicker is at 50Hz or over, your eyes would never detect it, regardless
of light situation.

 

On 03/06/2014 08:52, Sandman wrote:
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Your statement: "Your eye wouldn't be more or less suspectible to
noticing CRT flicker depending on enviromental lighting either." was
incorrect, unless you add the 50 Hz caveat.

Even then, that's just one example. Flicker has been reported on 60 Hz
displays as well, and likely on higher frequencies too. Fortunately, or
not, LCD displays have different characteristics.

 

That's implicit in the "CRT" part, which all are 50Hz or more.

By whom and when?

 

Good q. Of course considering the whole chain of equipment and processes
you can get flicker in the output from a 200Hz OLED...

 

Many moons ago, Lanier was one of the leading publishers of their
proprietary word processing system. When they came out with a newer
model, (which you had to buy to get continuing support,) I "upgraded."
The CRT screen flickered under fluorescent lighting, to a point where it
was unusable. I replaced it with an IBM as WordPerfect. Neither my IBM,
not Apple II monitors flickered. Your explanation was the likely
reason. That Lanier screw-up also saved me a lot of money. The Lanier
system cost about ten grand. IBM, with WP, considerably less. .

 

PAL is 50Hz, NTSC is 60Hz

The frame has no relevancy on the topic of flicker. NTSC is 60Hz, which is
far over the human's eye's capability to detect flicker.

As I said - 50Hz fields per second is far sufficient to avoid any detection
of flicker for the human eye.

No, only the refresh rate will be seen as flicker if it is low enough.

The flicker fusion threshold is 16Hz, and both PAL and NTSC far exceeds
this.

It is true, as should be noted here though, that our peripheral vision is
more likely to detect flicker, and back in the day, the CRT displays with
high refresh rates was born from the need when people started using large
computer monitors that were standing close to their eyes, so their
peripheral vision could detect a very slight flicker. That's when you
started seeing 100Hz and 120Hz monitors - and later, TV's - even though you
didn't really need it for a TV since no parts of it were ever in your
peripheral vision.