Hi fellow Zuiks
Earlier I wrote:
"Just suppose a set of lenses are all capable of clearly transmitting 45
lines/pairs (black & white, for example) per millimetre of film width, and a set
of photographs was taken with superlative care..
So, for the SAME subject, a 35 mm camera system would get on the
negative 45 x 35 = 1575 line pairs (ideally) on the longest side.
A medium format camera with 6 x 9 cm negative (this is the big end of the
medium format range) would get on the negative 45 x 90 = 4050 line pairs
for the same subject.
A 4x5 inch camera would get 45 x 125 = 5625 line pairs on the negative for
this subject."
I didn't really finish the discussion and bring it to its conclusion.
I should have added and will now, that if one uses a Technorama Camera,
with a 6 x 17 cm negative, it would get at least 45 x 170 = 7650 line-pairs on
the long side of the negative.
The conclusion I want to bring this to is that the crunch comes when you
want to print the shot for viewing and have to decide how much to enlarge the
image.
Suppose, for arguments sake, you decide that at least the detail of
equivalent to 15 line-pairs/mm are required on the print. That fewer will not
yield an acceptable impression of sharpness.
On the basis of the illustrative calculations above, the following would be the
maximum long-side prints you could make.
35 mm, 1575/15 = 105 mm
6x9cm, 4050/15 = 269mm
4x5 inches, 5625/15 = 375mm
6 x 17cm, 7650/15 = 510mm.
Naturally, lens quality affects all of this, but I think I have the argument
right,
although people may adjust the actual line-pair numbers to match common
reality, based on their better experience than mine.
Brian
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