On Sun, 17 Aug 2003 10:37:24 GMT, chibitul <ch1b1tul@eudoramail.com>
wrote:
700x digital is 70x the optical. Still, that works out to about a
13x10 pixel image or so. Which is rather useless, unless you find a
fuzzy pixelated image useful as an effect.
However, the digital zoom has more useful potential as the cameral
resolution rises. a 1.2M pixel camera can run double optical
resolution (20x for a 10x lens) and lose no pixels of resolution. It
*will* have to give up either some digital image stabilization or
light gathering (no longer using two to four CCD pixels per pixel of
video), but the image is nearly as sharp as the non-digital-zoom
version.
You can bump this up another factor of 2 -- 40x on a 10x lens) --
with that many CCD pixels, and still be within VCD or maybe VHS
quality of resolution. Depending on the final output target, this can
be useful. If nothing else, it helps you frame a distant shot by
allowing you to see the center area of the shot better.
Well, no, you can't really zoom on the PC later beyond the frame
size. Whereas a good digital zoom exploits some of the extra
resolution on the CCD, giving you some real increase in detail up
close, without losing "pixels". It isn't free -- the extra pixels are
otherwise used for something else -- but it is still better than
interpolating pixels which weren't captured in the first place.
Still -- most camcorders have digital zoom disabled by default.
Most of us never bother to turn it on, because it is far better to
simply move in closer for the shot than to use it, all things being
equal.
Some camcorders offer a two-level digital zoom. The higher quality
level limits the zoom range, striving to keep it no worse than 1 CDD
pixel per image pixel. For 1 megapixel range CCDs, this is only 2:1,
but it is about as good (and more convenient) as using an external 2:1
lens adapter. The other level is the push the pixels until you can't
tell what it is range, the 700x or whatever. This lower range digital
zoom stops you from going into the professionally and esthetically
unusable range of the process.
--
*-__Jeffery Jones__________| *Starfire* |____________________-*
** Muskego WI Access Channel 14/25 <http://www.execpc.com/~jeffsj/mach7/>
*Starfire Design Studio* <http://www.starfiredesign.com/>
