Re: PING: ALL YOU FILM LUDDITES !

On Mar 23, 11:37 am, Harry Lockwood <hlockw...@xxxxxxxxxxx> wrote:
In article <1174674821.132809.229...@xxxxxxxxxxxxxxxxxxxxxxxxxxx>,
"Scott W" <biph...@xxxxxxxxxxx> wrote:

On Mar 23, 8:06 am, Harry Lockwood <hlockw...@xxxxxxxxxxx> wrote:
In article <1174657161.960639.75...@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
"Scott W" <biph...@xxxxxxxxxxx> wrote:

SNIP here





Yep, 35mm film ain't nothin' but a 24(or more)MP digital camera in
disguise.

I would be great if this were true, but 35mm film falls far short of
being a 24MP digital camera. If it were like having a 24MP digital
camera you could get scans that looked something like these.
http://www.sewcon.com/largephotos/24MP_Photo.jpg
http://www.sewcon.com/largephotos/car_at_24MP.jpg

I am not saying scanned 35mm film is bad but if you want to start to
get up to the high MP areas and not have your pixels look like crap
you really need to be looking at MF or LF.

Scott

Scott

Scott,

I need a tutorial here. If I scan a 35-mm negative in my Nikon 4000 ED
at 4000 ppi, then a 1.5" x 1" (slightly less, actually) scan will
produce ~ 24 Mp, no?

Well closer to 21.5, but yeah about that.

And what about scanning with the 5000 ED, wouldn't that produce ~1.5x as
many pixels? I would think that increasing the resolution to the point
of resolving the pixels of the film, e.g., the grain, would be "useful,"
provided one is sufficiently above the noise floor (not a small point.)
Or, are you suggesting these pixels are empty, in the sense of having no
additional information? What am I missing?

I believe that 5000 ED has the same resolution as the 4000 ED, aren't
both
4000 ppi scanners?

I checked; you're correct. (Why'd they do that?)



Part of it is that you get empty resolution, you can test for this by
down sampling to 2000 ppi and back up to 4000 and look at the
difference, whereas there will be some difference it normally is very
slight.

Sure this is a valid comparison? Once you've down sampled, you've
thrown away pixels, and you don't get them back by upsampling. Whether
you can "see" the difference is a matter of the detector you use; it may
not be the human eye.
The point is if you can down sample say a 20MP image down to 5 MP and
then get back pretty much the same 20MP image by up sampling you have
to believe that the 20MP image was over sampled a fair bit.
The other thing that keeps scanned 35mm film from being the same as a
20 some MP digital is that a film scan will have a lot more noise then
a digital camera, this leads to a softer looking image.

Even at 16x multisampling? (Admittedly, it takes a bit longer to
acquire the file.)
The noise mostly comes from the film. There is debat about how much of
the noise is from grain or dye clouds vs the surface of the film. And
some scanners can get a cleaner scan then other, but the best film
scan I have seen still have a lot of noise in it compared to a digital
camera.


Film and digital are different and as such it is not easy to do an
apples and apples comparison. For film to match all the qualities of
a digital camera it would have to have the same low noise
performance.

This is what I was getting at in my reference to a noise floor.

For digital to match all the qualities of film it would
have to be able to capture the same fine detail. But even a fine
grain film is pretty limited and even when you just look at fine
detail captured a camera like the 5D pretty easily matches the best
that a color film, and most B/W films can do.

I don't know how to make the comparison for color, but the ultimate
usable resolution in the typical B&W film would be to resolve the grain.

But the 5D image will
appear far sharper partly because it will have higher contrast and
partly because it will have much less noise.

Both devices will be limited by shot noise (assume thermal noise is
same.) If you cram more and more pixels into the same area by making
the pixels smaller, eventually not enough electrons are involved to give
an acceptable Signal - to - (shot) Noise ratio. But I know you know
that.
At some point a digital sensor is limited by shot noise but film has
far more noise then just shot noise.

And you say that the 5D image will "appear" sharper because it will have
higher contrast. But is that a valid criterion for sharpness? And
can't I similarly modify overall contrast and edge contrast in PS to get
an "appearance" of a sharper image?

You can do some sharpening of a film scan but this will also make the
noise worse
so film is very limited in how much you can sharpen. Also film is
good at capturing very high contrast detail, but not so good with
lower contrast detail. And the high contrast detail that it captures
ends up being low contrast in the captured image.
Putting this another way film has a slow fall off in its MTF whereas
digital has a good modulation up to a given frequency and then drops
off rapidly. Whereas film might be able to resolve more line pairs /
mm when the target is 1000:1 contrast at a lower line pairs /mm
digital will have more contrast.


I hope you take these comments in the spirit they're intended.
Definitely not a pissing contest. (Not allowed on this new group!)
No problem at all with your questions, they are all very fair question
in my mind.

Scott

.

Relevant Pages

  • Re: PING: ALL YOU FILM LUDDITES !
    ... provided one is sufficiently above the noise floor ... 20 some MP digital is that a film scan will have a lot more noise then ... a digital camera, this leads to a softer looking image. ... higher contrast. ...
    (rec.photo.equipment.35mm)
  • Re: PING: ALL YOU FILM LUDDITES !
    ... get up to the high MP areas and not have your pixels look like crap ... of resolving the pixels of the film, e.g., the grain, would be "useful," ... provided one is sufficiently above the noise floor ... a digital camera, this leads to a softer looking image. ...
    (rec.photo.equipment.35mm)
  • Re: 35mm film scanner questions
    ... my scanner will do 6400dpi which can give me a 160Mg TIFF file ... For a start, the information you are pulling off of the film at that resolution is at a very low contrast - due to the vanishingly small MTF of the film, not to mention the original camera optics. ... Similarly, you gloss over the noise with some glib "anti-noise" filter statement without recognising that no filter can distinguish between signal and noise, so reducing noise also reduces the signal - of which you have already precious little anywhere near the limiting resolution of your scanner. ... It certainly isn't the equivalent of the 53Mp digital camera that your exceedingly naive assessment claims. ...
    (rec.photo.digital)
  • Re: Minolta dynax 7xi
    ... After using a 5MP Kodak digital camera for the past 5 years I've ... that's where ISO speed ratings come from. ... If you change it you will either overexpose or underexpose your film. ... low contrast negative but I've never tried this. ...
    (alt.photography)
  • Re: Minolta dynax 7xi
    ... After using a 5MP Kodak digital camera for the past 5 years I've ... that's where ISO speed ratings come from. ... If you change it you will either overexpose or underexpose your film. ... low contrast negative but I've never tried this. ...
    (alt.photography)
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