There are several ways to get wide screen and they differ per camera, so some research has to be done on a per camera basis, but here are the basics: (and the whole good, better, best thing is my opinion only and not really shared by the industry) I will try to limit the discussion to only SD as HD is native 16:9 and therefore quite straightforward.
First, a couple of basics for those who don’t know…. DV video, whether it is 4×3 or 16×9 uses the same pixel count, that being 720×480 (or in some cases 720×486 the difference is not material to this discussion) You will notice that this is neither 4×3 or 16×9, but something in the middle. The difference is in what they call “pixel aspect” in the digital world. For 4×3 each pixel is narrower then it is tall. the width is roughly .9 the size of the height. For 16×9 the width is roughtly 1.25 the height or wider then the height by a sizable margin. This means when you are looking at a 4:3 perfect circle in a native 720×480 square pixal image the circle looks “fat”. If you are looking at a 16:9 image in 720×480 then the circle looks really thin.
Now, how do you go about getting the altered images on tape? there are sevearl ways.
The best IMHO is to get a camera with a 16×9 “native” image block. You will have to do some research here to find out if it is really native or if the camera manufacturer is playing games with thier definitions. A native image block will capture all the data then squeeze it into the anamorphic (squeezed) format required to store it on tape. What you DON’T want is a camrea that is takeing LESS then 480 lines of resolution top to bottom. You don’t want them cheeting your vertical resolution to make a 16×9 image. When you are shooting 4:3 with this camera you are likely going to not be using the outer pixels of the image block but this SHOULD be okay. You need less horizontal pixels for a 4×3 image then for a 16×9 image.
A second, very good way (and in some ways more fool proof) is to use an optical device on the front of the lens to opticaly squeeze the picture the correct amount to image it on a standard 4:3 sensor. I like this method because it is so foolproof and you 100 percent sure of what the camera is doing. but technicly it is not as good as having an image sensor with a wider pickup.
The last way to get a 16×9 image out of a camera I have already alluded to, and that is by playing games with the pixel count. IE you take a normal 4×3 sensor and lop off some pixes top or bottom to get what you want. I don’t like this because it does cost you resolution. If you are going to do this you might as well shoot full screen 4:3, protecting for the top and bottom, and just mask it in post. You are doing the same thing in the camera and you gain some options by doing it in post instead.
Now, in most of these systems the 16×9 image gets stored on tape as a “full frame” 720×480″ picture. The objects in the frame are just skinneyer then they should be. Some camera systems store the 16×9 as “letterboxed” IE a black band on top and bottom with the picture looking normal. YOU DON’T WANT THIS. You are giving away resolution with this system. You always want to create the letterbox later in the process, when you actualy need it. You never want to store it on tape that way.
Hope this helps at least a little. If anyone has other thoughts or corections to this please hop in.
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