LCD screen movement ?

berengar

Do LCD TV's have problems with movement ?

Are CRT TV's better at showing movement ? Not like its losing frames,
but maybe things 'blur' more when they move in LCDs, or maybe its just me.

Laguna

What you're seeing is the result of a lower refresh rate than a CRT T.V, "Response time" to be precise. The lower a response time (measure in milliseconds) an LCD TV has, the less trails/blurs you'll see, a 4ms or 8ms LCD TV is good, but as your trails and blurring seems to be very noticeable, your screen must have a refresh rate of 16ms or 25ms. There's nothing you can do to fix it I'm afraid, it's an inherent part of LCD technology ..

berengar

Hmmm, it's not so annoying, how do i find out the refresh rate
?
ive looked online at the tech specs but theres nothing, its a sony and
i hear sony are pretty secretive

Laguna

Secretive?, nah, the refresh rate of your T.V should be no big secret, it should be in the manual or on the product page on the site, are you sure it didn't specify something like refresh rate 25ms or something?. To be honest, if it's noticeable visually, it's got to be in excess of 16ms..

berengar

i found another site that says 50hz ?
http://audiovisual.kelkoo.co.uk/b/a/ps_14080399/100311823.html

i presume this is the same refresh rate ?

Laguna

No, the 50hz has nothing to do with the millisecond refresh rate of the screen, for example, my TV displays at up to 100hz and has a refresh rate of 8ms, they're two different things altogether.

berengar

So whats the 50hz then ?

Laguna

It's the display setting for the T.V., it's the European standard as opposed to the American standard which is 60Hz, it's sort of hard to explain really, it's to do with the frequency of the wavelength of how it displays the signal (or input, in the case of the T.V, the DVD or TV channe)l you're watching. Most TV's here (and yours I'd vouch), can display the superior 60Hz and some even upto 100Hz.

berengar

does it have much effect on picture quality ?

ZENER

PAL Video signals use a 50Hz field rate. This means it displays 50 fields interlaced to display 25 frames per second. NTSC displays 60 fields (30 frames) each second in America.

LCD panels are capable of these 50 or 60 frames (Hz) displays. The problem is that as each field is displayed on the screen it takes a finite period of time for that image to dissappear completely. If you were to flash 1 frame onto the screen at its normal rate - 20ms - it will take (for a 25ms LCD) 25ms for the image to disappear. If you now display a series of images in quick succession each image takes 25ms to fade out. this is what causes the motion blur on slow (>20ms) LCD panels. Once the image has faded before the next one arrives then you shouldn't notice any blur hence display speeds of <20 ms are required for 50Hz PAL pictures.

Theres another problem here though. Most LCD screens use a scan doubler which increases the refresh rate or frame rate to 100 Hz. This means 100 pictures per second being displayed. For each image to fade out before the next arrives the screen must have a response time of <10mS.

The motto is you get what you pay for. Those seemingly cheap screens in AHRRGUUS probably have response times in excess of 20mS. This is also why 2 seemingly identical screens - say 32" - may be displayed side by sisde but have a price difference that leaves you scratching your head, now you know why - faster screens cost more !!

ZEN

berengar

Cheers for that, you dont know by any chance (or where i could find out)
the response time for this one the Sony KLV-23HR3 :

http://www.sony.co.uk/view/ShowProduct.action?product=KLV-23HR3&site=odw_en_GB&pageType=Overview&category=TVP+LCD+TV

Its not in my manual and ive looked on the net and all i can find is that
its got a 50hz refresh rate ? does that mean that its 20ms response ?

ZENER

A few sites suggest that other similar models such as: KLV-S23A10

KLV-S23A10
23 inch BRAVIA LCD, Generation 7 Panel, Resolution - 1366 x 768 - WXGA , Contrast Ratio- 1000: 1 ( S 23 - 800: 1), Viewing Angle - 178 deg, Response Time - 8 ms , Brightness - 480cd/m2 ( S23 - 500cd/m2), Wega Gate, Light Sensor, PC Input

Although other sites quote 10mS for this screen. Nothing specific on your model though. The best thing to do is to go and demo the screen at a Sony center or store. There are still some older 640 x 480 (with perhaps slower response times ?!) models from Sony doing the rounds so be careful what you buy.

The refresh rate or frame rate are independent of the response times for a particular LCD panel and aren't really related in any way other than as described above.

ZEN

berengar

cheers, Also heard that even though it has WEGA written on it and the
manual, it doesnt actually use the WEGA engine ?
surely this is illegal ? false advertising ?

ZENER

If you search the 'net you'll find that Wega and Wega Engines appear to be 2 different things. Wega is a brand applied to certain models or a family of equipment supplied by Sony that have a similar look or presentation while Wega Engine is in addition to this and enhances the technology within the Wega range. It seems you need to look for Wega Engine to avail of the enhanced features/performance of the Wega range.

Maybe someone more in the know with Sony gear can clarify this. My explanation is based on two seperate searched in Google - Wega and Wega Engine, each yielded different results from Sonys' sites.

ZEN

berengar

Sony got back to me and told me it has a response time of 10ms ?

I couldn´t believe it and demoed a few others at 8ms and I could
still notice some drag, maybe im being way to nitpicky, but CRTs do they have a response time of virtually 0ms ?

Snake Plisken

I have to say I'm worried, about buying LCD/Plasma with low (50hertz) refresh rates, I've a bit of dodgy right eye that for some strange reason can pick up the flicker on a Monitor or TV display at 50 hertz, thats why my main set is a Panasonic 100hertz and my CRT montitor is set to 85 hertz. I will probably buy a Samsung 32" R61 for the bedroom and see how I get on with that before investing in a replacement screen for the sitting room.

Rgds

Snake