"w4jle" W4JLE(remove this to wrote in
:

Refresh rate. Your used to seeing a 60 Hz refresh rate (actually two
alternating frames at 30 Hz) on your home TV.

If you go to Europe, you go nuts for the first few days getting used
to the flicker as they use a 50Hz refresh rate.

What a half correct and half junk science answer!

Yes here in the UK we have a refresh rate of 50Hz on our PAL standard
sets compared to 60Hz on NTSC standard TVs but I can't think why it would
drive you nuts? If that's the case, you should be going mad constantly
when looking at PC monitors, EPOS displays and ATM machines as most have
different refresh rates from 47Hz upwards!

The reason is correct as at the top - refresh rate or more a sync problem
- when a computer monitor is 'filmed' but the camera used is not
'synced' to monitor's refresh rate, you see the monitor at one rate being
filmed at another - hence a mismatch.

Really the camera operator should lock the scan rate of the camera to the
refresh rate of the monitor, then both are at the same rate and you get a
steady image with no flicker!

Simple as that and now pretty much a feature on most professional video
cameras.

Brian.

On 8 Jan 2004 18:44:20 GMT, Brian Potter wrote:
- when a computer monitor is 'filmed' but the camera used is not
'synced' to monitor's refresh rate, you see the monitor at one rate being
filmed at another - hence a mismatch.

Actually, the correct term is "beat."

73's
Richard Clark, KB7QHC

It drives me nuts, because at the 25 Hz frame rate I can see the flicker.
After a few days in Merry Ole', I get used to it and don't notice it.

Every trip back to England requires a day or so to get my brain to ignore
the flicker. The other monitors you refereed to do indeed have 47 Hz refresh
rates, but they are non-interlaced video.


"Brian Potter" wrote in message
...
"w4jle" W4JLE(remove this to wrote in
:


Yes here in the UK we have a refresh rate of 50Hz on our PAL standard
sets compared to 60Hz on NTSC standard TVs but I can't think why it would
drive you nuts? If that's the case, you should be going mad constantly
when looking at PC monitors, EPOS displays and ATM machines as most have
different refresh rates from 47Hz upwards!

and the persistence (?) of the tube will play a part in perceived flicker !!

Nick