A scientific approach to proving whether man landed on the moon - photogrammetric rectification

Brad Guth wrote:

Bob Monaghan recently had this to say:
http://groups.google.com/group/rec.p...bbe950330f1dd4
Film Film Dmax Contrast [n.b. 4096:1 is 12 stops]
Vericolor 5072 (neg-pos) 3.9 D 8000:1
Kodachrome 25 3.8 D 6300:1
Kodachrome 64 3.7 D 5000:1
Ektachrome 64 3.7 D 5000:1
Ektachrome 100GX 3.8 D 6300:1
Ektachrome 100plus EPP 3.8 D 6300:1
Fuji Velvia 50 RVP 3.8 D 6300:1
Fuji Velvia 100 RVP100F 3.8 D 6300:1
Fujichrome EI 100 3.6 D 4000:1

in short, lots of us work with films which have 12 or more
stops of dynamic range.
http://palimpsest.stanford.edu/byaut...al-projection/

Brad Guth

---------------------------------------

In that same USENET thread there is this reply to the above:

From Stephen H. Westin
Date:Tues, Nov 30 2004 2:53 pm

"....No, it claims that these films are capable of producing densities
with
those wide ranges. Not the same thing. And it's wrong. They take the
Dmax as the contrast range, which isn't true unless Dmin is zero.

For example, the Velvia RVP data sheet AF3-960E shows a Dmax of around
3.8 for two of the layers, but only about 3.3 for the red layer.
Anyway, the Dmin looks to be about 0.2 for all three layers, so even
the green and blue layers are at about 4000:1 contrast, not the 6300:1
listed above. The red layer is about 1300:1 contrast.

But I thought we were talking about the exposure range of the film,
i.e. the input, not the resulting output. The exposure range to drive
the film from Dmax to Dmin is about 3 log units (-2.5 to 0.5), so the
range of exposures to which it will respond (with a response that
might be detectable in the developed film) is only about 1000:1, or 10
stops.

Similarly, Ektachrome EPP shows a contrast range from 2.85 to 3.65
density steps (700 to 4,500), depending on the layer. And its useful
exposure range seems to be perhaps 300:1 to 1000:1.

Keep in mind that when we talk about Dmax and Dmin, we're not in the
realm of good, or even acceptable, photographic reproduction. We're
just talking about the information that is theoretically present at
some level on the film. You would have to have a very good scanner and
some careful digital processing to hope to turn this into something
that's actually visible.

The page to which you refer is a bit scary; this guy blithely
quotes specifications without having measured what happens in the
real world. I've measured a video projector with rated contrast
of 500:1 or so; its installed performance was about 70:1. Likewise,
it's wonderful that film can produce over three orders of magnitude
of contrast, but stray light in a real projector limits that to
about 100:1.

------------------

Of relevance to this thread:

".....Keep in mind that when we talk about Dmax and Dmin, we're not in
the
realm of good, or even acceptable, photographic reproduction. We're
just talking about the information that is theoretically present at
some level on the film. You would have to have a very good scanner and
some careful digital processing to hope to turn this into something
that's actually visible."

wrote:
Brad Guth wrote:

Bob Monaghan recently had this to say:
http://groups.google.com/group/rec.p...bbe950330f1dd4
Film Film Dmax Contrast [n.b. 4096:1 is 12 stops]
Vericolor 5072 (neg-pos) 3.9 D 8000:1
Kodachrome 25 3.8 D 6300:1
Kodachrome 64 3.7 D 5000:1
Ektachrome 64 3.7 D 5000:1
Ektachrome 100GX 3.8 D 6300:1
Ektachrome 100plus EPP 3.8 D 6300:1
Fuji Velvia 50 RVP 3.8 D 6300:1
Fuji Velvia 100 RVP100F 3.8 D 6300:1
Fujichrome EI 100 3.6 D 4000:1

in short, lots of us work with films which have 12 or more
stops of dynamic range.
http://palimpsest.stanford.edu/byaut...al-projection/

Brad Guth

---------------------------------------

In that same USENET thread there is this reply to the above:

From Stephen H. Westin
Date:Tues, Nov 30 2004 2:53 pm

"....No, it claims that these films are capable of producing densities
with
those wide ranges. Not the same thing. And it's wrong. They take the
Dmax as the contrast range, which isn't true unless Dmin is zero.

For example, the Velvia RVP data sheet AF3-960E shows a Dmax of around
3.8 for two of the layers, but only about 3.3 for the red layer.
Anyway, the Dmin looks to be about 0.2 for all three layers, so even
the green and blue layers are at about 4000:1 contrast, not the 6300:1
listed above. The red layer is about 1300:1 contrast.

But I thought we were talking about the exposure range of the film,
i.e. the input, not the resulting output. The exposure range to drive
the film from Dmax to Dmin is about 3 log units (-2.5 to 0.5), so the
range of exposures to which it will respond (with a response that
might be detectable in the developed film) is only about 1000:1, or 10
stops.

Similarly, Ektachrome EPP shows a contrast range from 2.85 to 3.65
density steps (700 to 4,500), depending on the layer. And its useful
exposure range seems to be perhaps 300:1 to 1000:1.

Keep in mind that when we talk about Dmax and Dmin, we're not in the
realm of good, or even acceptable, photographic reproduction. We're
just talking about the information that is theoretically present at
some level on the film. You would have to have a very good scanner and
some careful digital processing to hope to turn this into something
that's actually visible.

The page to which you refer is a bit scary; this guy blithely
quotes specifications without having measured what happens in the
real world. I've measured a video projector with rated contrast
of 500:1 or so; its installed performance was about 70:1. Likewise,
it's wonderful that film can produce over three orders of magnitude
of contrast, but stray light in a real projector limits that to
about 100:1.

------------------

Of relevance to this thread:

".....Keep in mind that when we talk about Dmax and Dmin, we're not in
the
realm of good, or even acceptable, photographic reproduction. We're
just talking about the information that is theoretically present at
some level on the film. You would have to have a very good scanner and
some careful digital processing to hope to turn this into something
that's actually visible."

kmmpost,
Thanks for all the terrific photographic information that's interesting
and usable.

Keep in mind that when we talk about Dmax and Dmin, we're not in the
realm of good, or even acceptable, photographic reproduction.
Absolute horse pucky! That Ektachrome film was absolutely super
terrific, double-IR thermal proof and rad-hard as all get out.

Do you have any doubts whatsoever that a raw solar illuminated Venus
would have been rather easily recorded?

Remember that we're not talking about the whole target area of our moon
or that of Earth, but that of the grain per grain or pixel per pixel
and worth of the available DR as being worthy of accepting nearly 10
f/stops for the sort of photographic information that I'm talking
about; and otherwise as to how much dimmer was our moon or Earth than
Venus?

You folks do realize that the solar spectrums of deep-blues, violet,
near-UV and UV-a were those of significantly greater intensity than or
their artificial xenon lamp spectrum, and that the unfiltered Kodak
film (color as well as B&W) was in fact extremely sensitive to that
range of the spectrum.

I'd fixed that date typo and rechecked a few other matters. Is there
any chance that yourself or others you know of can run off these three
Apollo missions, of examining via a good 3D simulator as to working
through each of their A-11, A-14 and A-16 missions, for obtaining those
better numbers and of generating that much better 3D simulated look-see
at Venus?
-
Brad Guth