Digital Looks Good On CRT, Bad On LCD

[Randy 0]

As our customers slowly move from VGA CRT computer monitors to LCD, the number of complaints is increasing. Many are replacing the LCD simply because it frees up desk space not because the CRT is bad.

 

Their digital recorder looked good with the old CRT but terrible with the new LCD. Has anyone found a brand of LCD that will reproduce video worth a darn?

 

I started blaming the DVR until I viewed the same DVR from another office using a CRT instead of LCD.

 

Randy

[rory 0]

Depends on the LCD .. first it has to be in its Native Resolution ...

so youd want to get a LCD that specs as (depending on the DVR) 1024x768 or 1280x1024 .. anything other than Native generally can be pretty bad. Need to also look at the Contrast Ratio.

 

For example this should be a good one ..

ViewSonic VA903b / 19" / 8ms / 700:1 / SXGA 1280 x 1024 / Black / LCD Monitor

 

And this one should be great (another $80 extra though)

Viewsonic VP930B / 19" / 8ms / SXGA / 1280x1024 / 1000:1 Contrast Ratio / Black / LCD Monitor

 

I havent used either but plan to at some point. I am using a Viewsonic 19" Widescreen right now with a Geo Card though and it is great. However the Native Resolution is 1400x900 so no good as a Clients LCD .. as the DVR is in a smaller window .. but its still sweet.

 

Ofcourse either way, right now, a CRT will still produce a better image .. but with a decent LCD you should be able to get away with a decent image.

 

Also, the higher you go with resolution,. the lower the camera's video quality gets, as you are blowing it up more, since it is processing the camera's video in either 640x480 or 720x480 for example .. depending on the DVR and its settings .. and the camera also can make a difference. . a 350TVL camera ..well thats being blown up from 400 some pixels to 1000 or 1200 .. so that all compiled together only aggrevates the situation. .

 

PS. Im not an LCD expert bTW, just talking from what ive used (or seen in use/tested) so far which doesnt compare to what ive used or tested with DVRs and cameras.

[spyguy 0]

I've been using LCDs exclusively for a while now.

 

The only complaint I have that wasn't already addressed is that burn-in seems to occur much faster.

 

One customer went big with a few 52" LCD screens to display Geo CenterV2. The screen shot was really a sight to be seen...I think we got 42 cams per monitor. The drawback came when a month into use we decided to also utilize a few of the auxiliary input channels on the monitors....only to find 42 nice little windows burned into the back ground of the screens.

[kensplace 0]

LCD's can suffer from image persistance, but usually when a problem like that occurs you can eliminate it by either turning of the display for a long time, or displaying a totally white background (or a exact opposite image of what was causing the problem). If displaying a white image turn the brightness down to extend life of the backlight and leave it on for a long time.

 

LCD's should not normally suffer from burn in faster than a crt, but I have not used any of the big screen ones, maybe they suffer from it bad. (actually, its not burn in like on a crt, as it does not actually burn, they just get a memory effect that can usually be reversed by doing the above)

 

There may be a bit in the manual for the lcd about it, but its often buried deep in some never read area.

[osity 0]

We sell lots of LCD's in my line of work and contrast ratio on LCD's has gone all the way up to 1400:1 on some brands.

 

Your retina can resolve a contrast ratio of around 100:1 at any given moment and 1,000,000:1 after about 30 minutes. So i wonder how importand this number really is if you occasionally view your footage 10 minutes at a time. Sounds like you would have to spend hours staring at the screen to utilize all that contrast ratio

 

Strange that even by using the DVI option on LCD's hence keeping the signal in Digital format, the quality is worse than an analog CRT.

 

 

I read here that there are CCTV CRT's? What are the main differences between a regular CRT and a CCTV CRT?

[rory 0]

Hi osity,

 

Depends, if it is a TV CRT that is much lower res, like 250-350TVL, while CCTV CRTs can be anywhere from 500TVL to 1000TVL .. much more crisp image overall. There are low res ones also, but mostly those are the OEM ones. I cant give you any tech reasons why, just from using all of them they are much higher quality for live video.

 

As to PC CRT's and CCTV CRT's, I cant give you the technical on that either, but it really depends if the DVR has VGA or Composite Outputs. The CCTV CRT is much better quality (Crisp) than the PC CRT, but only when using a Composite Input (Eg. DSP) from the DVR.

 

Actually anyone installing CCTV should have at least one CCTV Monitor, this being a CRT CCTV Monitor .. even if it is only a 9" BW Monitor .. the 9" BW Monitors are typically 1000TVL and provide great quality for focusing of cameras, in fact I would not trust the focusing of cameras to anything but a CCTV Monitor (unless one is using something like FMSystems Camera Master).

 

Overall though, analogue, even on a simple TV, will be higher quality (to our eyes) from a composite input, than that on a PC CRT or LCD from a PC based DVR system ... if composite is put on a PC (VGA) Monitor though .. the quality is normally horrible.

[osity 0]

Hmm.... im a tad confused. A Regular TV will look better to our eyes than a PC monitor? I though the high resolution on a PC monitor would made it a great choice. Perhaps there is a difference between resolution and TVL

 

 

I have a PC based DVR system (w/ nv5000 card). Which display do you suggest for viewing and focusing? (brand or link to a couple please)

The video card has a VGA connector.

 

Neat topic!

[rory 0]

Well the best way is to just take a camera that is pluggd into the current PC DVR and put it into a TV .. a 13" TV would be much better than say a 19" TV for example, and a decent brand CCTV Monitor will blow all of them away .. ive used Samsung and GE (Kalatel) Monitors in the past.

 

I dont know the tech behind it, but a PC CRT cant touch a CCTV CRT BUT that is for composite. ..

 

As to the nv5000 card, Im not familiar with it but I believe it is an Avermedia Card, either way the DVR and the cameras are really not related as far as initial setup goes.. the cameras should be focused and set up seperately, preferably at your location and only installed/adjusted at the clients location. But that can differ from job to job.

 

But cameras "should" be focused with a CCTV CRT for optimum quality.

 

If it is a PC DVR then an LCD is nice, and thats all we sell for those, its not the best quality .. but its that or the PC CRT ... and well the size of a CRT, and then who wants to buy a PC CRT these days ... well actually who wants to buy ANY CRT these days .. however if the card has a DSP output then you can also use a CCTV CRT Monitor for better quality ..

 

Example:

[osity 0]

Yes it's avermedia. http://www.aver.com/products/nv5000spec.pdf

 

So ideally I should have my computer hooked up to an LCD just for PC usage purposes and and the composite on the DVR card going to a CCTV CRT for surveillance monitoring?

[501 0]

I have to agree. I went to an old customers site to do and install and was so impressed with the system we had put in for them 3 years before because it was quite old, but the quality was perfect. Then I realized, it was the old monitor. Very weird that it would look better then a new 19 inch LCD.

[rory 0]

Yes it's avermedia. http://www.aver.com/products/nv5000spec.pdf

 

So ideally I should have my computer hooked up to an LCD just for PC usage purposes and and the composite on the DVR card going to a CCTV CRT for surveillance monitoring?

 

Yes, if live image quality is what you are after ..

Generally, unless the client specifies, we use an LCD these days, due to the size of the CCTV CRT. But ultimately the CCTV CRT will produce the best image with CCTV cameras.

[osity 0]

I saw my first cctv crt yesterday actually. It was "capture" brand.

It was huge, and by that I mean that it looked like a mini fridge and not like a regular CRT monitor.

 

The images were very jittery. (like an incorrect refresh rate setting) I was not impressed by that at all. Is that jitternetss expected from a cctv crt?

[rory 0]

no, dont know what that was .. bad connections or cables or power probably..

plus those are OEM so monitors wont neccassarily even be high resolution. Could be a difference of a few hundred $$ also in price from a name brand.

[CollinR 0]

You can also just try a regular old TV, I never buy real CCTV monitors anymore.

[osity 0]

Regular old TV vs. a computer monitor? You would choose the tv??

[CollinR 0]

It all depends on the install, if they need local control obviously they get a computer monitor. If they want a monitor (or second, or third...) say behind the cash register unless they already have a "CCTV monitor" they get a SD TV. I can't justify the cost difference between the two, that display will never be used for identification or review so it doesn't need to be anything special. As was mentioned 330, 350, 380, 420 and 470 line cameras look better on 330-480 line TVs then they do all blown up on HD displays like computer monitors.

[osity 0]

It seems strange that it would look better on a regular TV as opposed to a computer monitor which can be adjusted to any resolution you want (i.e 800x600, 1280x1024)