Interesting Leica product announcements today ...

Discussion in 'Digital Photography' started by Bruce, May 10, 2012.

  1. Bruce

    Peter Irwin Guest

    Um, there is a big difference between seeing grain patterns,
    even (barely) seeing some individual grains, and "actually
    recording the shape of grain particles".

    I would be astonished if anyone could even guess at the
    shape of individual grains based on what is visible in a
    grain focuser.

    Peter.
     
    Peter Irwin, May 16, 2012
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  2. Bruce

    Noons Guest

    Chris Malcolm wrote,on my timestamp of 16/05/2012 9:38 AM:

    and colour as well. Cibachrome.
    Yup. Around 15X blow-up, THEN and only then I used the grain focuser to FURTHER
    magnify the image. And yes, the grain would be visible. With slide film and
    Cibachrome.

    The case pointed here was Tech Pan. Have you ever tried to focus Tech Pan using
    that technique? I can promise you a very big surprise. The same goes for Adox
    CMS20 and the "Rollei" clones.
    Still got mine. AND a microscope.
     
    Noons, May 16, 2012
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  3. Bruce

    Noons Guest

    Peter Irwin wrote,on my timestamp of 16/05/2012 8:40 PM:
    And with Tech Pan I defy anyone to tell me when they are "seeing" grain...
     
    Noons, May 16, 2012
  4. Bruce

    Noons Guest

    David Dyer-Bennet wrote,on my timestamp of 16/05/2012 11:06 AM:
    No you CANNOT. Not with Tech Pan. THAT is the point. Stop changing the subject
    to match your "theories": it won't work.

    Ah, so a scan is a compressed TIFF image? Care to translate into the Queen's
    language?

    NO one was talking about Tri-x. Like I said: stop evading the subject.

    NO they are not.
     
    Noons, May 16, 2012
  5. Bruce

    Trevor Guest

    Right, you should have said that then. Doesn't include many digital P&S
    though.

    Trevor.
     
    Trevor, May 16, 2012

  6. I have lots of Tech Pan negatives, so I was going to
    look at them with my excellent microscope.

    But what I found first was Tri-X.

    At 100x all I could actually resolve was grain clumps. At 400x
    (N.A. 0.75) I could see individual grains, and resolve some
    but not all. At 1000x (N.A. 1.30) I could resolve all the grains.
    There is a huge variation in grain size, and in clumpiness.

    Then I looked at Tech Pan. There are no clumps. And the grain
    size is far more uniform. I actually need 1000x to truly resolve the grains.
    It really can't be done at 400x, though that is perfectly adequate
    to see the individual grains. Resolution is clearly limited
    not by grain size but by emulsion thickness.

    But can you see the grain "structure" at 50x in Tech Pan?
    Yes, you can ... the fluctuation in density is easily seen.
    In fact, at background density you can see individual grains
    at 50x, but they are far from resolved. At ordinary density
    you see only fluctuations and the image itself. The bottom
    line is that at background density you should indeed be able,
    with a good enlarger lens ( at f/4) and a grain focuser,
    to actually focus on the grains themselves ... but they
    won't be resolved at all. You will be seeing little gray spots,
    not black.

    Doug McDonald
     
    Doug McDonald, May 16, 2012
  7. No, the point is that in general grain is the limiting factor to
    "satisfactory" enlargement of film images.
    I was looking for something he might have meant by saying the scanned
    size depended on film ISO. One thing he might have meant is that the
    file size of the scanned image as stored on disk is larger for high-ISO
    films.
    Um, look around you at the newsgroup, where many people are using it
    exactly that way.
     
    David Dyer-Bennet, May 16, 2012
  8. Bruce

    K W Hart Guest

    Just out of curiosity, how does noise reduction know what is noise and what
    is fine detail in the photo?
     
    K W Hart, May 16, 2012
  9. There is no "135mm" film size. There is "135" film and there
    is "35mm" film. So which is it?
    Are you an idiot?
    Or are you just trying hard to be one?

    Noone --- except you! --- says you're to photograph the whole
    image in one go under the microscope.
    Post the URL with the proof, that's less work than that handwaving
    of yours.
    Google for >>drum scan service<<.
    That isn't *that* complicated.
    Even you can manage that.

    -Wolfgang
     
    Wolfgang Weisselberg, May 16, 2012
  10. Bruce

    J. Clarke Guest

    People still claim that, and they're as wrong now as the ones who
    claimed it in the '30s.

    The real story is that a mathematician (some sources say Prandtl, some
    say Ackeret, some say Sainte-Lague) was asked the question at dinner and
    did a back of the envelope calculation based on many simplifying
    assumptions, and a biologist, Antoine Magnan, presumably the one who
    asked the question, assumed that that was the definitive word and put it
    in a biology text that he was writing. Magnan credits Sainte-Lague, who
    was not an aerodynamicist.

    The real story here is that one who can't do the math oneself should not
    report the results of another's work without first consulting with that
    person and making sure that one is telling the correct story.
     
    J. Clarke, May 17, 2012
  11. Dunno, the software I use most (Noise Ninja) is proprietary code, and
    it's outside my area of expertise anyway. I just know the results are
    generally useful on pictures that have significant noise to begin with.
    I don't believe it *does* know in any magic and perfect sense of "know";
    it just uses reasonably successful algorithms to guess.
     
    David Dyer-Bennet, May 17, 2012
  12. Bruce

    Noons Guest

    Like I said: I defy anyone to focus Tech Pan in an enlarger at 10X mag
    with a grain focuser. It just won't work. Note that it doesn't mean
    one cannot use a grain focuser to do it: the technique just has to be
    adjusted.
    I doubt that 50X blow-up of Tech Pan equates to 18MPixel scanning
    resolution as claimed by Clark. 50X from 35mm is an image 1800mm
    wide. One would need a pixel width of around 21000 to get to that
    size at a rez of 300dpi. In fact, I'd say 50X mag would border on the
    need to scan at 15000dpi. If one could find an affordable scanner
    capable of such.
    Therefore, I stand by what I claimed: Clark's "18Mpixel equivalent"
    for Tech Pan is a load of bullshit.
    According to Luminous Backyard guy, those are the same as "pixels".
    Bwahahaha!
     
    Noons, May 17, 2012
  13. Bruce

    Noons Guest

    For someone who suggested to "photograph the microscope output" as an
    answer to "Only wish I had a scanner capable of much higher rez to
    show it at its best. ",
    I can't possibly increase the level of idiocy from yours..
    Ah, ok. So that would be a solution for "Only wish I had a scanner
    capable of much higher rez to show it at its best. " exactly and
    precisely how?
    Oh wait: you mean I should photograph in themicrsocope multiple
    fractions of the frame and waste my life stitching them together? I
    like photography, not computer playing time in case you haven't
    noticed.

    I did, many times before here and elsewhere. If you think I'm gonna
    get involved in that sort of url bullshit again, you got another thing
    coming. Go search back in time if you are really interested, I still
    have most of the images up in the various sites. WOuld you like me to
    point you at a Canon digital image where it is CLEAR the noise
    reduction is selectively destroying resolution? Can't get that with
    film, you know...
    I have used google long before it became "trendy" for people like
    you. There isn't a drum scanner anywhere near me.
     
    Noons, May 17, 2012
  14. Just out of curiosity, how does noise reduction know what is noise and
    The statistics of the group of pixels.

    David
     
    David J Taylor, May 17, 2012
  15. That may have been where the original story came from. But there's
    more to it than such a simple overgeneralisation. We now know how
    bumblebees manage to fly. They use very specific kinds and timings of
    wing trajectory which enables them to capture some of the energy in
    the edge vortices the movements create. It's making use of a
    completely new kind of lift which was previsouly unknown and
    unsuspected. Until that was discovered and understood further more
    detailed investigations of bumblebee flight simply discovered in
    greater and more precise why the bee couldn't fly as well as it did,
    i.e. why the theoretical models being employed were missing something.
     
    Chris Malcolm, May 17, 2012
  16. Of course. The problems arise when you don't just want to use one
    channel, you simply want the freedom to mix and match channel
    contributions without having clipped or severely underexposed any
    channel.
     
    Chris Malcolm, May 17, 2012
  17. True, but it makes the important point that losing information is not
    necessarily a problem. It's only a problem if the information lost
    matters and there isn't a usable way of acquiring it.

    For example my spectacles weren't perfect when new and are now pretty
    old and scratched. They lose a lot of information, plus they add
    misinformation in the form of reflections and chromatic
    aberration. Nevertheless I can see a hell of a lot better when wearing
    them because what they gain is a lot more important, and a lot less
    easily avoidable, than what is lost.
     
    Chris Malcolm, May 17, 2012
  18. I now know that what I was referring to as grain others are
    referring to as not grain but grain clumps. Fair enough. With a good
    grain focuser and good enlarger optics you could definitely see the
    shape of the dark outline of these grain clumps. That's how I
    focused the enlargement, I got the crispest edges to the grain
    clumps.

    It may be relevant to point out that I'm seriously short sighted,
    which means that when doing exacting visual work I take my specs off
    and get my eyes close to the subject. By doing that I can easily see a
    lot more detail than most normal sighted people can see with a good
    magnifying glass.
     
    Chris Malcolm, May 17, 2012
  19. Bruce

    Noons Guest

    David Dyer-Bennet wrote,on my timestamp of 17/05/2012 2:14 PM:
    NN and Neat Image work by identifying in reasonably small and "smooth" areas of
    the photo what is not smooth. Then they use that as a sample to identify in the
    rest of the image identical patterns/frequencies and apply an averaging
    lagorithm to them - for all intents and purposes, a selective blur. Usually
    they work well in the chroma and reasonably less well in the luminosity
    channels. But overall they can do a very good job. The problem of course is
    when using "raw" files that are pre-processed for noise no matter what, like the
    Canon Digic ones - not the only ones doing it, either...
     
    Noons, May 17, 2012
  20. Bruce

    Noons Guest

    David Dyer-Bennet wrote,on my timestamp of 17/05/2012 2:47 AM:
    Hence why folks use TechPan-like film when they want much smaller grain. And
    why mentioning Tri-X as an "example" for grain of Tech Pan is inappropriate.

    My largest scanned tiffs - on average - are definitely the ones taken with Ektar
    100, Provia 100, Astia, Velvia 50, PanF and Adox CMS. Fuji 400 and 800, Kodak
    Portra 400 and Tri-x are smaller. But you are right: it all depends on how much
    detail any given image has, to start with. A low-speed film tiff with almost no
    detail will be smaller than one with some detail taken with 400ISO film. And
    that relationship goes for digital as well, of course. What has to be taken
    into account is the nature of the file used to store the image. It is useless
    to compare with jpg files: they work by REMOVING detail in the first place! They
    cannot ever be employed as a base of comparison of detail.

    Yeah, sure. Which newsgroup? The rec.photo.digital.slr-systems one? Sorry, I
    prefer to get my info in places dedicated exclusively to film use. Usenet is
    the biggest source of film mis-information I've found in the last 15 years. Most
    of the "knowledge" there is by folks who last used film 15-20 years ago, and
    didn't know way back then how to use film properly to start with. And who have
    made no effort whatsoever in improving that knowledge since. Hence why I expose
    the "tri-x is same as Tech Pan" comments for what they are: mis-information, in
    this context.
     
    Noons, May 17, 2012
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