Re: [Leica] [Partly Relevant] The Economical Leica and Future Film

["Patrick G. Sobalvarro" <pgs@sobalvarro.org>]

Noel H. Charchuk wrote:
> 
> John raises a good point about 35 mm film stock for movies, if we ever do
> go digital for still photography, movies will probably still be shot on 35
> mm for a long time yet, because the storage required for a movie would be
> massive if it were to be done digitally.

It may be the case that 35mm film will not disappear for an
extra-special long time, but it won't be because the movie industry is
supporting it to avoid the cost of digital storage for movies.  Let's do
a little arithmetic here:

2.5 hours * 3,600 seconds/hour * 24 frames/second = 216,000 frames in a
movie.

35mm movie film is what we would call half-frame, so each frame is good
for at most 2K x 3K pixels (this is a generous estimate).  Assume we
record 48 bits/pixel, or 16 bits/color channel.

216,000 frames * 6,000,000 pixels/frame * 48 bits/pixel * 1 byte/8 bits
= 7,776,000 megabytes.

MPEG II compression rates are typically about 10 to 1, giving us 778
gigabytes for the whole movie.  At today's consumer prices (what you get
if you walk down to your consumer electronics store and buy an 8GB
disk), disks cost about US$40/gigabyte, for a cost of about US$31,000
for storing a movie at quite high resolution.

Obviously for the entire movie's shooting you would need at least ten
times that amount of storage, but even if it were 100 times it would be
a small cost compared to that of making a feature film, and disk storage
costs have in recent years followed an exponential decay curve,
decreasing by a factor of two every 18 months or so.

So it would be possible to build the equipment to do this sort of thing
right now, except that development costs would be large and the
potential market small.  Still, the parts cost is small enough that I
would guess that within ten years most feature movies will be shot
digitally.

- -Patrick