do crt's have response times?

[w00t]

do crt's have response times? if yes than what?

 

[fierydemise]

CRTs have Hz rates, 80Hz is good for most some can handle 75Hz

 

[w00t]

dont lcd's have Hz too? the higher Hz is better correct? 96Hz good?

edit: i also noticed they have vertical refresh rates and Hz is horizontal refresh rate.

 

[fierydemise]

No LCDs don't have Hz rates, 96Hz is very good, don't bother with vertical refresh rates, just worry about the Hz rate being faster then 80Hz and you'll be fine

 

[Cheesetogo]

LCD's don't have refresh rates like crts. CRTs refresh at whatever their Hz is, but lcds refresh only when somthing chnges. FOr instance, the lcd does not refresh if it's just seeing the desktop and no movement, but a crt refreshes reguarless. (I think that's right)

 

[w00t]

if i have a higher Hz will i be able to see my frames per second i heard somthing like if u have a higher one you can actually see all the frames better than if u have a low Hz.

 

[fierydemise]

Hz rate has nothing to do with fps they do not corrolate in anyway (sorry if that wasn't the answer to your question I didn't quite understand it)

 

[Dr X]

I think you should spend some time on this site, because I dont know if you're quite grasping how it all works.

 

[corkyg]

Agree! Sim-listically, cathode ray tubes use electron guns to scan a beam of electrons on a coated glass surface (the tube). Liquid Crystal Displays currently use thin film technology to illuminate staring pixels embedded in the film.

CRT's refresh by means of the next scan - LCDs respond by the rate at which pixels can be turned on and off.

So, think LCDs stare, and CRT's scan.

 

[ViRGE]

Originally posted by: fierydemise
Hz rate has nothing to do with fps they do not corrolate in anyway (sorry if that wasn't the answer to your question I didn't quite understand it)

This is not correct. If your video card is set to synchronize frames with the screen refreshes(so-called vertical sync, aka Vsync), then your frame rate can never be higher than the refresh rate. Performance can even often end up being degraded if the video card can't render frames as fast as the monitor refreshes, since the video card needs to push the new frame to the front-buffer before it can start rendering another one, but the front-buffer can only be changed between screen refreshes.(ex: You have a frame ready 1/10th of the way in to a screen refresh, you must now wait for the other 9/10ths of that refresh to occur before you can show the new frame and render another).

As for the OP's original question, it's sort of loaded. CRT's work via phosphors, which only maintain their lit state for a very brief period of time before fading, at which point a new refresh takes place to re-excite the phosphors. In this sense, there is a response time, in that it takes (1000ms divided by the refresh rate) milliseconds to change a pixel, but there's not actually anything happening between refreshes, the pixel can just suddenly change colors on the next refresh. LCD's on the other hand have a true response time, where the crystals must be twisted to generate a new color, and this is a continuous operation that takes time.

The advantage here for CRT's is that because phosphors(and by extension pixels) can be changed immediately on a refresh cycle, everything changes uniformly. LCD pixel response time on the other hand varies depending on what color you're coming from and going to, so in any given frame some pixels will change faster than others. There's also the whole deal with the pixels on the LCD being between desired colors for a very short period of time, instead of a CRT always being the desired color.

 

[mordantmonkey]

Originally posted by: fierydemise
Hz rate has nothing to do with fps they do not corrolate in anyway (sorry if that wasn't the answer to your question I didn't quite understand it)

not exactly. tearing can occur if your refresh rate is alot lower than your FPS. a lot of people don't notice this, and even if you do it is usually pretty minor, unless there is a huge difference.
edit: damn beat me to it

 

[fierydemise]

Sorry about being misleading, what I was trying to say is that the response time of an LCD doesn't corrolate to the Hz rate of a CRT, thats like comparing apples to oranges.

 

[wchou]

Originally posted by: fierydemise
CRTs have Hz rates, 80Hz is good for most some can handle 75Hz

there is no such thing as 80hz but theire is 60, 70,72,75,85 and 100

 

[w00t]

Originally posted by: wchou

Originally posted by: fierydemise
CRTs have Hz rates, 80Hz is good for most some can handle 75Hz

there is no such thing as 80hz but theire is 60, 70,72,75,85 and 100

k

 

[knothead34]

i still think response time is important. for games at least better then 24ms i believe is the general rule.

 

[cubby1223]

For the sake of rough comparison, 25ms = 1/40 of a second, or saying a 25ms LCD pixel runs at max 40Hz.

 

[w00t]

this is what is up from what i read if ur Hz is how many times ur crt refresh's a second.

example: 85Hz = screen refresh's 85 times per second.

 

[Dr X]

hertz ( P ) Pronunciation Key (hûrts)
n. pl. hertz Abbr. Hz

A unit of frequency equal to one cycle per second


cubby1223 - your 'rough comparison' is so insanely wrong and irrelevant it's not funny. Response time and refresh rates CANNOT be compared between CRT's and LCD's. They're two completely different technologies.

 

[w00t]

if the human eye can only see 30 frames than why do we need 100fps and 80Hz? just thinking about it the human eye must be able to see more than 30.

edit: its like in games set ur max fps to 30 than put it to 100 u will see a diff.

 

[0roo0roo]

go read howstuffworks.com for crt and lcd.

 

[Dr X]

The human eye doesnt work like a computer game - that "your eye can see up to 30 fps" is just a mssive load of crap. Do some research on it, I'm sure you'll be surprised. A movie at the cinema only displays at 24fps, and it's perfectly smooth to the eye.

 

[0roo0roo]

Originally posted by: Dr X
The human eye doesnt work like a computer game - that "your eye can see up to 30 fps" is just a mssive load of crap. Do some research on it, I'm sure you'll be surprised. A movie at the cinema only displays at 24fps, and it's perfectly smooth to the eye.

you are so wrong.

http://amo.net/nt/02-21-01fps.html

film only works because of motion blur and the persistent image of a super bright image on your retina in a dark theater. motion blur does not work in games where objects are in precise locations. freeze a film frame of motion and you get a mess. games are rendered crisp frame after frame. you don't control the film camera either, if you did..at 24 fps, movement would not be precise or enjoyable. rotating 180deg in a second at 24fps is 7.5deg jump per frame, no precision. and thats being generous with the time.

 

[kobymu]

Originally posted by: Dr X
The human eye doesnt work like a computer game - that "your eye can see up to 30 fps" is just a mssive load of crap. Do some research on it, I'm sure you'll be surprised. A movie at the cinema only displays at 24fps, and it's perfectly smooth to the eye.

Quoting myself from a previous thread:

Originally posted by: kobymu
it is not as simple as that. there is a big difference in how the brain analys the visual input between still image and motion. most peple can distinguish up to 25 diffrent images pe second (ie a 1 minute video clip in which every frame is a complatly difference from one another), however in motion the brain does not process all the visual information that it receive and it can go as high as ~150 "fps" in low complexity scenes (ie a video clip of black ball in motion on white backround, the brain will only process the information of the black ball and some of the white background, and more specifically the immedate white background aroud the black ball).
i read somewhere about an experiment that prove the above statment. and one of it's conclusion is that because "in the jungle" it is very impotent to notice movment for survival, our brain evolved in such a way that it specialise in distinguishing movment (as in opposed to distinguishing the differences between two different images), "it knows" what information to process and what information not to process.

and like all other homen capabilities it can differ from one to another to some extent.
ie the 25/150 cap limit is not absolute.

 

[imported_miahallen]

www.tomshardwareguide.com wrote an article on this exact subject this past September, and they measured what they qualified as the Latency of a CRT, it was 860us (that's u=micro), which is equal to 0.86ms compared to the very best LCD they had on hand for the test rated at 20ms. It's quite a difference...

"In the absence of other standards, we use rise time from 10% to 90%. For my part, and despite the low opinion one might have of this standard, it is a valid measurement. Rise time from 10% to 90% is used successfully everywhere for characterizing electronic components. Also, the pixels of a TFT are above all first-order systems, and I have never observed oscillation or even overshoot. Consequently, rise time from 10% to 90% appears seems to be quite a valid measurement.

We observe, for example, for the CRT:

Rise Time:
A measured rise time of 35 µs - that is, a response that's about 400 times faster than that of an average TFT. Of course it is a delicate matter to speak of rise time for a CRT, since once the beam has passed over the pixel, the latter begins to fade progressively. Thus a permanent state, and consequently a rise time, can't really be defined.
If you look at the previous graph more closely, you can even detect the illumination of the successive pixels. The distance between two pixels works out to the horizontal refresh rate confirmed by the monitor's own OSD.

Fall Time:
We use the same method here as for rise time. In fact, the human eye is more sensitive to fall time than to rise time. A white object that leaves a "trail" will be more inconvenient than a white object that takes time to illuminate when moving. Based on our observations, certain manufacturers don't hesitate to "pre-load" their pixels at a lower value before any color change. By doing this, they reduce fall time, but to the detriment of rise time.
On our CRT, the fall time, in fact, corresponds to the display's remanence.

Here we measure 825 µs, which remains beyond the capabilities of the best TFT panels. All we have to do is add the rise time and the fall time to obtain the latency time:
Tl = Tf + Tr = 860 µs"

 

[Dr X]

Originally posted by: 0roo0roo

Originally posted by: Dr X
The human eye doesnt work like a computer game - that "your eye can see up to 30 fps" is just a mssive load of crap. Do some research on it, I'm sure you'll be surprised. A movie at the cinema only displays at 24fps, and it's perfectly smooth to the eye.

you are so wrong.

http://amo.net/nt/02-21-01fps.html

Did you actually read that article? It supports what I've said - the human eye DOES NOT WORK LIKE A COMPUTER GAME. We dont see 'frames per second', because there are so many factors involved. The human eye doesn't "refresh" 30 times a second.

If you're in a well lit room, and the lights flickered off for 1/20th of a second, would you notice it? Yes. What if they flickered off for 1/200th of a second? Most people wouldn't. If you're in a light room, and a light quickly flashes for 1/20th of a second, would you notice? Yes, and same for 1/100th, and even 1/200th or higher. Hang on, what if you're in a well lit room, where the lights were spontaneously flickering off for 1/200th of a second constantly. You probably wouldn't specifically notice, but the room wouldn't feel 'right'.

Do some research, mate, and I think you'll find it's not as simple as saying 'our eyes can see up to 30fps'.