What is Upper Field & Lower Field?
 

Hi guys,

I would lke to learn the difference between upper field & lower field please.

I am sure that there are a lot of people like myself who have no idea as what they are the purpose for it. Which one you choose and when (i.e) for SD & HDV and ....


Thanks in advance
Matthew

http://en.wikipedia.org/wiki/Field_(video)

A field is half of a frame, formed by taking every other line horizontally. The upper field is the half that starts comprises the odd lines, starting from the first. The lower field is the half that comprises the even lines, starting from the second.

Upper and lower refer to interlaced video. On NTSC TVs, each frame is drawn 60 times a second on the screen. The photon guns draw every other line (upper, or odd) then go back and do the others (lower or even.) It does this because our power cycles at 60 Hz. If you want to take a still from a video with a lot of motion, you need to deinterlace it. Otherwise you will see jaggy lines where there was a lot of motion. These lines are the two fields. If you are playing your video on a regular SD TV, you don't have to do anything. If you are playing back primarily on a computer, you might want to deinterlace to avoid these jaggy lines.

Edward, that is a great explanation on the subject and I now understand it better. Thanks.