768H x 494V; How can the TVL spec vary so much?

[videobruce 0]

I know it's called marketing, but exactly how can a 768H x 494V (effective) chip have different resolution specs, especially from the same manufacture??

 

I see specs from 460 to 550 TVL from the same 1/3" 768x494 spec. This includes from the same manufactur(s).

[phred 0]

Tolerances for chip design are so stringent that a production run of the

same CCDs will give a range of qualities.

 

Similar thing happens with CPUs, some will get hotter than others when

tested so are given a different speed rating.

[videobruce 0]

Tolerances are one thing, but doesn't explain a swing from 450 to as high as 600. A few percentage maybe, but not 10%. The resolution is usually directed related to price.

[survtech 0]

The higher numbers are usually for cameras with Pixim chips. These chips have slightly higher resolution than standard chips. Also beware of quoted specs. The maximum resolution for NTSC color is typically 520 to 540 TVL. I don't believe that an analog color camera is capable of better than that. But some manufacturers using day/night technology spec their camera resolutions in the B/W mode, which can produce 600 TVL resolution.

[phred 0]

Price difference can be more than 100%.

Look at the price of intel Conroe CPUs – same core processor, some can run fast and some not so fast.

There is a wide range of price/quality for CCDs

Other factor in camera price is the performance of the processing chips inside the camera.

 

If this was not the case then all cameras would be equal.

 

Also survtech is right about Pixim, they are giving Sony a bit of a bashing at the high res. end of the market

[rory 0]

Most high res BW cameras are 570-600TVL ... or at least capable of that.

Day/Night is the same, just once they add the chroma to the image it decreases in quality. These are typically Sony CCD Chips.

 

From what ive seen Pixem is typically Cmos with less low light sensitivity.

[videobruce 0]

Most high res BW cameras are 570-600TVL

I was only refering to color.

[videobruce 0]

I received a reply from NUVICO regarding specs on two PTZ cameras. The cheaper (newer) one had a higher TVL than the more expensive.

Their response is here;

 

Dear Bruce,

Z18 PTZ is 480 TV Lines. It's not the CCD in PTZ that determines the TV

Lines in PTZ Cameras. There are more mechanisms involved. It is the actual

zoom module itsef.

In abstract, the PTZ10 is the latest zoom module in the market to serve

various needs where 18 optical zoom is not necessary. Bottom line, PTZ10 is

using the latest zoom module technology. Therefore, it has the capability

to display the TV lines at 550.

 

Sincerely,

Mike Kim

Technical Sales Manager

NUVICO