If youâve spent any time online searching for a used car, youâve probably seen ads for manufacturer-backed certified pre-owned (CPO) programs offered through dealerships. While you may be tempted to avoid heading to the dealerâcars for sale by private owners can be found all over Craigslist and other third-party sitesâa CPO vehicle can be a good choice for some buyers.
In the context of a CCTV camera TVL (TV Lines) refers to the horizontal resolution (the maximum number of vertical lines the camera can resolve) of the CCTV camera. TV Lines are the standard measure of an analog TV's Resolution. Rather than represent discrete locations on a grid, as Pixels in a digital Frame do, TV Lines indicate the maximum number of identifiable changes that can be produced along a single (horizontal) Scanline of an analog TV.
We suggested that the external flash be set to the TTL mode. The TTL (i.e. , T hrough T he L ens) mode means that the camera will measure the output of external flash and stop the flash once illumination is sufficient.This is the easiest mode of using external flashes.However, do keep in mind that the Coolpix 990 is not true TTL cameras in terms of flash control. It measures flash illumination with a flash sensor next to the on-camera lens as shown below. As a result, what this sensor sees is usually not what the lens sees.his is the easiest mode of using external flashes. However, do keep in mind that the Coolpix 990 is not true TTL cameras in terms of flash control. It measures flash illumination with a flash sensor next to the on-camera lens as shown below.