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Originally Posted by
Dick Applebaum 
First, your overall response to the question is very good. What many fail to realize is that for a revolution to mean anything (historically) it [mostly] requires for the
revolution to be successful, No?
I have intermingled some comments and questions where appropriate.
Can you elaborate on this? I have a Panny hdc-sd1 that has 12x Optical Zoom and beaucoups Digital Zoom.
Mostly, I use the cam to capture the grandkids soccer games and I usually sit at midfield -- so the action is up to 50 yds away. The 2-5x Optical is fine for most cases, so I seldom use the digital... there are times tho, where I want to zoom on the face or legs of a player-- goalkeep, free kick, corner kick, etc.
Are you saying that this new iPhone camera system has the possibility of equalling a 5x optical zoom? If so, that's big... really big!
Generally, cameras and camcorders have a certain amount of resolution that customers expect to be their quality level at all times. When using optical zoom, assuming that zoom to be of good quality, that expectation is realized.
But when moving to digital zoom, which I call digital cropping, that's no longer true. If you have a camera with a resolution sensor that you bought because of that resolution, AND you use that resolution correctly, then you will notice a big drop in quality when using digital zoom. Of course, because it removes the outer pixels when zooming. The more you zoom, the fewer pixels are left for the picture.
If you're going to use the still images from a phone for let's say, Facebook, then the digital zoom will be great. Those pictures are of low quality and resolution, so you won't see the difference. But if you want to make an 8 x 10 print, that's different. There will be problems when you zoom out too much.
Camcorders are different. The amount of resolution you get is what the sensor offers, usually. Some camcorders do have higher rez sensors, but you can't use them that way for reasons I won't get into now. But what normally happens is that as soon as you activate the digital zoom, you're going below the resolution of the format. So if you have, say, a 720p camcorder, you will have a 1280 x 720 sensor (likely, you won't. The 720 will be there, but you may have 1024 x 720 at the sensor.).
Now, because your resolution is what the format needs, when you digitally zoom in, you're removing those needed pixels. So you move down in quality from the very beginning. You may end up with 480 x 270 or so, possibly even lower. This results in a pixelated image. Very unpleasant.
But a camera with a higher resolution sensor should have pixels to spare. So when you use that digital zoom, you're still within the proper resolution for the format, unless the digital zoom moves past the point where you're at the minimum.
If the sensor is pretty small, and has poor noise and dynamic range, as phone sensors do, IF, and I say if, because it isn't always true, the manufacturer properly binns the pixels at the low end of the zoom, at 1x, then you could get great noise and dynamic range. If they don't do it properly, then you won't. Pixel binning is a technique where the extra pixels are averaged together and the noise can be removed to a certain extent, and dynamic range increased. It's sort of a reverse interpolation. In other words, you're interpolating the image to a lower res output. Some manufacturers just add the pixels together without doing any work to work the noise out, so there's little benefit.
When you begin to zoom out, there are fewer pixels to binn together, so noise increases. This isn't too much of a problem with video as opposed to stills, because we don't notice noise as much with moving images as we do with static ones.
Because of that, this video camera COULD have a very good image because of the backlit sensor, which has better sensitivity and less noise from the start. That is, if Apple is doing it all right, including the software in the phone.
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Ahh... the VHS- BetaMax wars. My Dad was an audiophile. Hie built his own Hi-Fis, Speakers (Stuff like base-crossover circuitry, folded horns- small night-stand-size devices where the sound emerged at the back and bottom from an internal folded-horn then used the walls and ceiling of the corners of the room to complete the effect. He could make a candy dish jump off a marble coffee table on the other side of the room. Anyway, we would argue, and he would prove to me (audibly, and visually on an oscilloscope) that BetaMax was vastly superior..
Audio was my business for a number of years when I was a partner in a pro audio manufacturing firm, so I understand that bit pretty well.
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But, AIR, the thing that won the war was the early formats were limited to 1 hr BetaMax vs 2 hr VHS... You could program your VCR to tape a 1-2 hr movie on TV with VHS. You had to be there [to switch tapes] with Beta! Convenience trumped quality!
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Well, Beta did well for several years. Sony fixed the early problems vs. VHS. But the smaller cassette size limited the amount of tape that would fit inside. So they lost the consumer war, but came out with Betacam, which dominated the pro video area until digital replaced it.
Listen to the sounds of your destination instead of "Humpty Dance" for god's sake! 
