Image Quality: LED & LCD vs. CRT

[hazim 0]

Dear all.

 

I used to install CCTV systems. Nowadays I'm installing 700TVL CCD Sony Effio-2 cameras which gives high resolution image. These cameras for example gives excellent image on the old CRT monitors/TVs, but worse image on LCDs and LEDs. I noted that big LED and LCD screens require using VGA or HDMI inputs rather than RCA for high resolution image. So I bought good DVRs with HDMI output to get the best possible image. After trying HDMI, I still see the CRT image is much better.

I made a quick search on the net and noticed that there is special screens for CCTV, but anyway it's hard to get such screens in my area. Is there a specific LCD/LED brand that is able to give a really high resolution image for CCTV?

Note that I tried changing the output resolution for the DVR and didn't get any real difference.

 

This is the DVR that I'm using:

http://www.icatchinc.com/eng/pt_spec.php?id=20120928003

 

Regards,

Hazim

[StanLee2066 0]

Dear all.

 

I used to install CCTV systems. Nowadays I'm installing 700TVL CCD Sony Effio-2 cameras which gives high resolution image. These cameras for example gives excellent image on the old CRT monitors/TVs, but worse image on LCDs and LEDs. I noted that big LED and LCD screens require using VGA or HDMI inputs rather than RCA for high resolution image. So I bought good DVRs with HDMI output to get the best possible image. After trying HDMI, I still see the CRT image is much better.

I made a quick search on the net and noticed that there is special screens for CCTV, but anyway it's hard to get such screens in my area. Is there a specific LCD/LED brand that is able to give a really high resolution image for CCTV?

Note that I tried changing the output resolution for the DVR and didn't get any real difference.

 

This is the DVR that I'm using:

http://www.icatchinc.com/eng/pt_spec.php?id=20120928003

 

 

What size screens (CRT vs LCD) are you comparing? What is the output of the camera - is it standard NTSC (480i) using composite?

[hazim 0]

I mean any CRT TV size. 32" and bigger LCD/LED. The camera is analog 700TVL, it has BNC output. The system is PAL bot NTSC.

The idea is that any good camera gives good and clear image on CRTs while worse image on LCDs and LEDs, even when using VGA and HDMI output from DVR to the screen.

[survtech 0]

There are better quality LED/LCD CCTV monitors. Check out Orion Images and ViewZ.

[StanLee2066 0]

I mean any CRT TV size. 32" and bigger LCD/LED. The camera is analog 700TVL, it has BNC output. The system is PAL bot NTSC.

The idea is that any good camera gives good and clear image on CRTs while worse image on LCDs and LEDs, even when using VGA and HDMI output from DVR to the screen.

 

The reason I asked about monitor sizes, is because I've experienced many situations where users watch media on a 21" CRT, then are disappointed when the picture looks worst on a 32" or higher LCD/LED. it just won't look as sharp and clear. That's completely normal and what you might expect hooking up the cameras directly to the TVs. If you are comparing with identical TV sizes, then you shouldn't notice much of a difference unless you are using a really old LCD (original LCD TVs had growing pains, especially when it came to contrast).

 

There are exceptions. Many DVD players for example are capable of up-converting an SD signal to a higher level (HD) when using HDMI. It's not as nice as an original source HD signal, but does make a noticeable difference.

 

The question is, does your DVR up-convert the digitized PAL (576p) to a higher resolution before sending the signal to HDMI? If not, it could also explain why you see no difference in picture quality. Although just occurred to me that the higher analogue resolution of these cameras (compared to regular CCTV) when digitized by DVR and sent to LCD/LED should actually help with the general larger display size of these monitors. Could it be this feature is turned off in the camera? It can probably be disabled so an image could be sent directly to a regular analogue PAL CRT.

[hazim 0]

It's not an "old" LCD, it's an LED screen that have HDMI input which mean it's not old for sure. It's hard to find Orion and ViewZ screens around here. Thanks StanLee2066 for your help, but I'm wondering if the problem is because I used Cat-6E cable (2 cables, each for four cameras) along with 350m passive video baluns. The distance isn't big at all, say 20m for the first cable and 40m for the second cable. I used UTP to reduce cables. Here is info about the balun I used.

 

I should have tried connecting a camera to the DVR directly and see the result, but didn't. I'm far form the installation place. When I go there I'll try it.

 

Regards,

Hazim

[hazim 0]

I checked the system today and tried a similar camera to the ones installed, I connected it directly to the composite input of the screen and got a very good result. I connected one of te installed cameras via CAT-6 directly to the screen and get that same bad result that I'm facing. In conclusion, sending video via UTP + baluns makes some distortion to the video signal which will affect the image quality, while coaxial cable doesn't make distortion.

[icamera 0]

I had problems with Baluns also. They work well on a test bench, not so much when there are sources of interference.

 

I ran some Cat6e drops under vinyl siding horizontally for a distance of about 35 meters. The distortion and rolling image was terrible. My small 7 inch test monitor showed a great picture. The larger TV monitors in the premises all showed varied degrees of rolling image and distortion on image. Replaced with RG59 siamese, problem gone.

 

Cat 6 drops left in place for future upgrade path to IP.

 

 

I checked the system today and tried a similar camera to the ones installed, I connected it directly to the composite input of the screen and got a very good result. I connected one of te installed cameras via CAT-6 directly to the screen and get that same bad result that I'm facing. In conclusion, sending video via UTP + baluns makes some distortion to the video signal which will affect the image quality, while coaxial cable doesn't make distortion.