Archived posting to the Leica Users Group, 2001/03/18

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Subject: Re: [Leica] Digital Downsides
From: Stanislaw Stawowy <watteau@email.com>
Date: Sun, 18 Mar 2001 12:50:45 -0500 (EST)

Thank you, Steve! It is a interesting article, indeed.

I made some math for myself, maybe someone will find
it interesting:

1. One "digital pixel" is made from at least 3 pixels,
usually 4 (R+G+B+additional gray).
2. Typical film, exposed by typical advanced photographer,
exhibits at least 80 lpmm.
3. At 24x36 mm our young photographer can record
24x80 = 2000 points vertically and 36x80 = 3000 points
horizontally, giving average 6 000 000 points.
4. To record image with similar resolution, digital camera
needs 4 x 6 000 000 = 24 000 000 pixels. So we need a 24
megapixel monster.
5. To store that image in 32 bit color (True Color),
we need 6 000 000 x 4 (there is 8 bits in byte) , e.g.
24 MB.
6. Assuming we are using JPEG compression and image has
an average level of detail, we still need about 6-8
megabytes per image.

Not enough? Now let's try other example:
A.)
My Summitar (at f/5.6) photos needs 6000x4000 pixels
scans to at least average number of details and
tonality from my original photo (on APX 100).
It gives about 100 MB image, about 24 MB JPEG
compressed.

B.)
My Rodenstock MF photos needs at least 8000x10000 pixels
scan do record all details from film. Typical scan is
about 400 MB. Or 150 MB JPEG compressed.

Where to store it? How should I act when my baterries
dry out? How will moisture affect my camera operation?
How should I make photos in Winter, at -10 - -20 degrees
Celsius?

Yours very sceptical
- -------------------
St.


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