Just a not too technical question/comment. (Please not too technical answers :). I've seen several posts addressing the size of the current ccd sensors and comparing them to the film size for 35mm and APS, etc. Since the sensor size is smaller than the 35mm film size the equivalent lens performance is such that a normal 35mm lens (50mm) becomes telephoto, etc. Yet the smaller the ccd size/larger pixel count, etc is pushing the state of the art. Wouldn't a larger sensor be somewhat easier to deal with along with giving the mfr the option to use the existing lens technology. Since you could use the center portion of the lens/picture, many of the less than optimum effects such as vignetting, distortion seen around the edge of current pictures might be reduced. A true cynic might suspect that changing lenses and mounts, etc, will result in new sales of "systems" to compare/compete/replace existing (and "obsolete") products. I'd sure like to use my existing Minolta equipment (lenses, flashes, etc.). I'm not a "pro" and have neither the cash flow nor write-offs to fully replace so much of my gear.

-- Craig Gillette (cgillette@thegrid.net), November 22, 1999

Answers

I had a hard time following your question. It sounds like you're asking why they don't use bigger CCD's, and expressing a desire to use your existing 35mm lenses.

1) bigger CCD's cost more

2) bigger CCD's require bigger, heavier, (and probably much more expensive) lenses to get the same focal length. Ever wonder why mavica is the only camera with really high zoom? Because they're the only camera using smaller than half inch CCD. Okay, they got a nice 5x zoom on the 505 with a half inch CCD, but that lens is huge for a digicam. Likewise the Oly 2500 uses a 2/3 inch CCD, and requires a lot bigger glass to get the same zoom. The canon pro 70 also uses a bigger CCD. 3) Marketing wise, digicam makers figure they can milk the 35mm SLR crowd for lots of extra money for the privelege of using their old l

-- benoit (foo@bar.com), November 22, 1999.

I had a hard time following your question. It sounds like you're asking why they don't use bigger CCD's, and expressing a desire to use your existing 35mm lenses.

1) bigger CCD's cost more

2) bigger CCD's require bigger, heavier, (and probably much more expensive) lenses to get the same focal length. Ever wonder why mavica is the only camera with really high zoom? Because they're the only camera using smaller than half inch CCD. Okay, they got a nice 5x zoom on the 505 with a half inch CCD, but that lens is huge for a digicam. Likewise the Oly 2500 uses a 2/3 inch CCD, and requires a lot bigger glass to get the same zoom. The canon pro 70 also uses a bigger CCD -- it has a big lens but still doens't quite get to 3x zoom. 3) Marketing wise, digicam makers figure they can milk the 35mm SLR crowd for lots of extra money for the privelege of using their old

-- benoit (foo@bar.com), November 22, 1999.

oops, dunno what happened here, never done that before. Read the second reply insead of the first. :

-- benoit (foo@bar.com), November 22, 1999.

Despite manufacturers calling their CCD arrays 2/3 inch or 1/2 inch, in reality the sensor area is only about 8mm by 6mm, nearer 1/3 inch if truth be told. The rest of the chip is taken up by the multiplexing circuitry. This means that each pixel is about 5 microns (.005mm) across, and the size of individual Red, Green and Blue sensors is approaching the diffraction limit for optical resolution. Any future substantial increase in the number of pixels will simply have to use a larger sensor area.

Current economics would seem to dictate that it is cheaper to fit very high resolution lenses than to make bigger silicon. Hence at present we're stuck with 3:1 zooms with ridiculously short focal lengths.

I'm sure that all this will change in the near future, CCDs will get cheaper to make in larger sizes, and the price of precision optical components will continue to rise. Don't throw away those old 35mm lenses just yet!

-- Pete Andrews (p.l.andrews@bham.ac.uk), November 23, 1999.

I think the problem you all have is you have just been looking at the wrong cameras. Now take a Kodak DCS620, for example, it is made from a Nikon F5 and the digital stuff added by Kodak. Thus standard Nikon lenses can be used.

The picture taking CCD is 22.5x15.2 mm which is still 60% smaller than 35 mm film. There is two more lcds, one for viewing and one for status. This is a really nice digital camera and is only $16,000 list price. (sixteen thousand us dollars) Last time I wrote about this camera, they thought the price was an error. It is nice to know that better technology is available, but just too expensive for most of us.

This info came from Digital Camera magazine. It does have some very interesting articles.

-- Dave Clark (daveclark@mail.com), November 23, 1999.

That was basically my concern, there is a huge pool of highly developed and effective lenses in the top manufacturer's lines. The 35mm camera system bodies support significantly more photographic flexibility. It seems to me if the current sensors are close to diffraction limitation in their resolution, then going up in size, that is closer to the 35mm image size, is the way to go. But what we are getting at this point is a choice between a system that for most of us would be a down payment on a house or a glorified point and shoot that requires a significant concurrent investment in accesories (memory cards, readers, computer storage, etc,. The Oly 2500 is a case in point, it seems well ahead in the digital environment but it's roughly equivalent to existng Oly point and shoots that are easily $1000 less. I can buy a lot of film and developing for that $1000. I've got my first two rolls in for PhotoCD. For most of us non-pro's (not in business) the more we could carry-over exisitng equipment, the faster we could move over. Guess I'm going to have to be frustrated for a while.

-- Craig Gillette (cgillette@thegrid.net), November 25, 1999.

Exactly. I think everyone is frustrated by this problem. I want to use my existing lenses, plus no digital camera I've seen has the closeup capabilities of the cheapest SLR with a macro lens. The large CCD arrays necessary (like the Kodak 1300 series) are several thousand dollars just for the chip. Now you need the camera and support circuitry to go with it. Because of the large size, you also need high capacity storage and can expect slower downloads than a smaller CCD. If nothing else, the quality of images produced by these arrays is stunning. Kodak has the specs for their various arrays on their web site. Though not for general purpose photographic use, you might find images made by astronomical cameras that use these arrays interesting. Try www.fli-cam.com.

-- Conrad Hoffman (choffman@rpa.net), November 25, 1999.

Certainly, it is a problem. For those of us on non-professional budgets, the quality of digital cameras is currently very limited compared to film, and we know that what we buy now will be superceded, in quality terms, next year.

With improved manufacturing, CCDs will get more pixels/mm, and physically larger. It is a slow but fairly continuous process.

Perhaps one day, I'll be able to afford a 35mm-quality digicam. Then I'll just have to save up for a 5x4-quality model... In the meantime, of course, digital does offer other, different, benefits.

-- Alan Gibson (Alan.Gibson@technologist.com), November 26, 1999.