[opendtv] Re: News: Your Next HD Buy May Be a Still Camera

  • From: "John Willkie" <johnwillkie@xxxxxxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Fri, 3 Oct 2008 13:06:54 -0700

Boy, I needed this comic relief today.

Let me see, as I remember it, the "excellent quality available with
professional (were there non-professional 35 mm movie cameras in the 1930s?)
movie cameras" was adopted by still cameras (I think Leica started that
trend)."

The only part of this that passes the smell test is that Leica's M1 was the
first camera to use 35 mm stock, at least to the best of my memory, but I
wasn't alive in the 1930's, and my father had yet to graduate from high
school.

But, the formats were different.  Film stock in movie cameras (and
projectors) travel from top to bottom.  The film gate is wider than higher,
and was fixed at 18x24 mm.  This is called the "academy" frame.

Film stock in still cameras travel laterally.  And, the film gate is wider
than higher, so it has a different orientation than do the movie cameras.
It doesn't have the same aspect ratio, nor the same size as film: 24 x 36
mm.  

Both take advantage of the fact that there is more than 24 mm between the
sprocket holes.

I also need to note that "early" Olympus 35 mm "half-frame" still cameras
did use 18x24 image size, but -- as anyone who has ever used these cameras
knows -- had a lower apparent quality than standard 35 mm images.  In many
cases, you actually needed to use an Olympus enlarger to get equivalent
sized images, because enlarger lenses are complementary to camera lenses.

You see, the lenses in the cameras are quite different.  A "normal" lens for
a film image is defined as the square root of the sum of the square of both
image axes.  So, for 24x36mm, that's 43.26 mm, commonly 50 or 55 mm.

For 18x24, the value is 19.28 mm, commonly 18 mm.

So, a "normal" lens for 18x24 put that is imaging a 24x36 frame provides a
wide-angle image of about 0.44 or so mag.  When you put a normal lens for
24x36 on an 18x24 frame, it amounts to a telephoto lens, with a mag of 2.29

I could go into "zones" and "edge diffraction", but one either knows this
stuff, or doesn't.

However, it's also funny to talk about 35mm "quality" on celluloid stock in
the 1930s.  The film grain was so big, particularly using the developing
chemicals of the era, that you could practically dine on it!

This is not exhaustive of my knowledge of the subject, Bert.  I can talk
about 8mm, Super 8, Super 16, Super 35, even the widescreen and "large
format" film.

All of this was known to me in the summer of my seventh grade year; more
than 40 years ago.

I guess this something else that reverends know via divine intervention, or
are taught in their engineering courses at the seminary.

Personally, I can't wait until a 66x66mm imager is made that can natively
record digital images at 60 fps progressive.  Last I heard, we weren't quite
there yet, but things are getting closer.  The largest digital backs these
days cost upwards of $12,000.  Cameras and lenses are extra.

John Willkie, who notes again that off-handedly, to make him appear more
knowledgeable than he really is, bert has gone deeply into territory that he
knows next to nothing about.


-----Mensaje original-----
De: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] En
nombre de Manfredi, Albert E
Enviado el: Friday, October 03, 2008 12:34 PM
Para: opendtv@xxxxxxxxxxxxx
Asunto: [opendtv] Re: News: Your Next HD Buy May Be a Still Camera

Craig Birkmaier wrote:

> In recent years, while watching the rapid growth of the digital
> still camera market and the "feature creep" that has allowed
> these cameras to capture short video clips, I have put forth
> the proposition that the path to consumer/prosumer HD image
> acquisition would come from the digital still camera market,
> rather than from the traditional video camcorder manufacturers.
> The key to this is simple - solid state memory. As the capacity
> of flash memory cards has grown the ability to capture useful
> length clips of video has become an attractive feature of these
> cameras.
>
> Now Canon is blurring the lines between still imaging and HD
> image acquisition with what the pundits are calling "a
> disruptive technology," the EOS 5D Mark II digital still camera.
> I'd just call it inevitable...

I'd call it sort of repetition of history, more than anything
disruptive. The difference being, now this very good video camera will
be available to the masses too.

In the 1930s, the excellent quality available with professional 35mm
movie cameras was adopted by still cameras (I think Leica started that
trend). Now the reverse is happening, where the excellent quality
available with digital still cameras, in large part due to the
relatively big lens and big sensor, is finding its way to movie cameras.

The common denominator being that relatively big lenses and large image
area provide for good quality images, both moving and still.

Bert
 
 
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