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16:9 widescreen mode: Myth, magic or both

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tjruberg
16:9 widescreen mode: Myth, magic or both
on Jan 12, 2003 at 7:10:48 am

I'm kind of new to DV but I'm trying to nail down the truth about DV camcorders 16:9 or widescreen mode. I have a Sony TRV310. The articles I've read around the WEB indicate consumer level DV camcorders DO NOT record in true 16:9 format. It has been explained like this:

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From: http://www.tfdvd.com/public/158.cfm

"Shooting 16:9

When you are recording to a digital format like Digi-Beta, D-9 or the different flavors of DV, you are never recording images more than 720 pixels wide. Even wide-screen images will always be contained in 720 by 480 pixels for NTSC or 720 by 576 for PAL at maximum, so it's a good idea to squeeze 16:9 images to anamorphic ratios or you'd limit the vertical resolution to 405 pixels only (432 in PAL), calculated as square pixels without any squeezing. Anamorphic squeezing can be done in real-time by camera electronics today, and the unsqueezing will be done by circuits in the player or display as well.

Since this is not an expensive feature any more, many DV-Camcorders offer the option to shoot wide-screen these days. But until recently only professional high-end cameras offered true 16:9 CCD-chips and appropriate lenses. The 'cheapest' one used to be the GY-DV700W from JVC at more than 10,000 U$ or next the Sony DSR-500WSP for around 20,000 U$ (both prices body only!).

Such a camera will use more CCD-pixels to expose a true wide-screen image and later squeeze them horizontally (and down sample too, see my last article). Now the DVCAM-version of Sony's TRV-950, called DSR-PDX10, is using the advantage of it's higher resolution chips (originally meant for megapixel stills) by reading more pixels in 16:9 to record a wider image at wide screen settings. Any other consumer camcorder or even 'prosumer' model will expose the same area on the chip horizontally as in 4:3 and crop the image at top and bottom to a 16:9 ratio. The resulting image will by scaled anamorphic to full DV-size by the camera circuits before it's recorded to tape. Such an image will show less image resolution vertically and you don't gain any wider horizontal viewing angle as compared to shooting 4:3.

Sony camcorders will at least show you an undistorted 16:9 image in their viewfinder. Canon's prosumer models are displaying the squeezed anamorphic image in their viewfinders, making it very hard to judge image composition. The newer XL-1S or the GL-2 (called XM-2 in Europe) are offering 16:9 guides.

But with any such camcorder you may as well decide to shoot in regular 4:3 while observing a 16:9 framing to crop and scale the footage as anamorphic later in post. The actual amount of information will be just the same, and you could even decide to generate two versions – wide screen and 4 by 3. BTW, even if the GL-2 / XM-2 has 1.7 megapixel stills capability; it's not using any higher resolution of chip for wide screen video."

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and this:

From: http://www.farnfilm.com/widescreen.html

"Consumer DV camcorders are only capable of shooting in standard 4:3 ratio. When shooting in what’s called "16:9 mode”, the units perform a process of cropping the image top-and-bottom (so discarding approximately a fifth of the information) and expanding it to fit the screen by duplicating lines using a cheap DVE.

In effect, instead of recording more horizontal information, they duplicate vertical lines - which is why, when playing back a recording on a normal television set, people look tall and thin: the image has been artificially stretched.

So this "16:9 mode" may look like widescreen, but it only achieves this by using a cheap trick."

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However, When I switch between normal and 16:9 on my Sony TRV310 I do in fact record more width. The top and bottom are cropped slightly but I am recording a wider view.

At this point I understand that True 16:9 would have more width without a loss of height. But none of the articles seem to indicate that a DV camcorder should be doing what my Sony is doing (actually recording more width).

Do I need to see a doctor?






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