Re: What is APS?

[P3D Michael Kersenbrock <michaelk@xxxxxxxxxxx>]

> The camera/imager combination you're talking about only has, at best,
> about one third the resolution of 35mm film.  The imaging chip isn't
> quite the size of a 35mm film frame, and number of pixels is "only"
> around 6 million (that's about 2500 by 2500 if it were square).
> Pretty impressive, but I've read that film captures the equivalent
> of anywhere from 4000 to 8000 "pixels" in the same space.

A third the resolution of 35mm film isn't too bad.  Won't hold up
to a Dr T. viewer?  How about for projection only?  I don't recall
having film-grain problems in projected views.

Again, if resolution needs to be improved by only a factor of three
in the next 10~15 years, that seems to be a very doable goal in
concideration of the last 10~15 years of progress.

> It's called a "thermionic heat pump".  But these things suck power.

That's the device's generic name, I was trying to think of the more
technical name. Named after a fellow, think it starts with 'J'.  Whatever... :-)

> Those coolers typically plug into your car battery through the
> cigar lighter socket.  You want to put a car battery into your camera?
> I admit it might make it feel more like a Realist...  Oh, and don't
> forget to turn it on an hour before you want to shoot.

I think cooling a chip of a couple grams of mass would take a little
less power than cooling a half-cubic-yard cooler.  It might do it in
less an hour as well.

> 
> >One also can just make the imaging chip bigger instead.
> 
> finer you make the grain, the slower the film.  It still takes a
> certain number of incident photons to record an image.  Those pesky
> laws of physics again.

There usually are way around it.  I won't suggest that I know anything
about which I'm talking (except for the electronics part) but aren't
there techniques that are essentially optical amplifiers that "multiply"
incident photon counts into higher counts?  I vaguely recall that the
CCD imagers that my previous company manufactured (Tektronix) did something
like that.  Don't recall exactly.... 

> Why is medium-format superior to 35mm?  It uses the same film, with
> the same intrinsic resolution.  It just uses more of it.  The analogy
> with a digital imager is more pixels, not larger ones.  But now the
> problem becomes one of yield.  The larger you make your chip, the harder
> it is to get one that is 100% functional.  That drives up the cost.

How does chip processing costs now compare with 1980?  I expect the trend
to continue such that 15 years from now, current processing will be
thought to be rather crude and expensive.

> worse than that, and I'm probably being generous.  The technology will
> have to improve by a factor of 2-3 times JUST TO CATCH UP TO 35mm
> FILM, let alone surpass it.  This kind of improvement is not a matter

Do you think catching up with 35mm film to be inadequate and that digital
cameras are unacceptable until they are significantly better?  Won't
auto-window-adjustment auto-masking auto-other-things be a sufficiently significant
improvement over current manual methods to be worthwhile?

> of successive refinement; some real breakthroughs are needed.  The sad
> part is that if people are willing to settle for what's available now,
> we'll never get there.

Don't know about you, but I think I could stand a better stereo photography
system than I'm using now.

> 
> 	-Greg
> 
> 

Mike K.


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