Optical illusion?

Discussion in 'Digital SLR' started by RichA, Jan 1, 2005.

  1. RichA

    RichA Guest

    Ever notice how a long distance shot doesn't
    ever look as sharp as a close-up shot?
    It's got to be some kind of optical illusion
    because lenses (I believe) are optimized for
    infinity imaging. But, case in point;
    When a friend was looking for a digital,
    I showed him two shots from mine, one a landscape,
    the other a macro. The landscape didn't impress
    him technically (sharpness, etc) but the macro convinced
    him to get the camera.
    -Rich
     
    RichA, Jan 1, 2005
    #1
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  2. Air is the difference. The light has to pass through more air, dust and particulates that
    effect the resultant picture. There are other optical aberrations that come into effect on
    long distance shots such as heat rising and temperature inversions.

    --
    Dave




    | Ever notice how a long distance shot doesn't
    | ever look as sharp as a close-up shot?
    | It's got to be some kind of optical illusion
    | because lenses (I believe) are optimized for
    | infinity imaging. But, case in point;
    | When a friend was looking for a digital,
    | I showed him two shots from mine, one a landscape,
    | the other a macro. The landscape didn't impress
    | him technically (sharpness, etc) but the macro convinced
    | him to get the camera.
    | -Rich
     
    David H. Lipman, Jan 1, 2005
    #2
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  3. RichA

    Ryadia Guest

    Interesting observation...
    I just decided to play around with panorama stich on my 20D. I also took the
    same shots with a GWS Fuji 120 roll film, pano camera. I don't think I'll be
    converting from film to digital for Panos just yet! It seems taht the
    further away you get, the less detail is recorded.

    Doug
     
    Ryadia, Jan 1, 2005
    #3
  4. RichA

    Ken Guest

    Besides the atmospheric obscurants inherent in any image taken over long distances the simple
    fact remains that digital cameras still have a long way to go with regards to sensor and image
    resolution. Objects that are small in an image are represented my just a few pixels and you
    cannot get a lot of sharp detail when you have so few pixels to work with.

    A fascinating project that is being worked on to produce Giga-Pixel images can be found at
    the link below.

    http://www.scienceblog.com/community/article4901.html
     
    Ken, Jan 1, 2005
    #4
  5. RichA

    RichA Guest

    But it's using a conventional film camera, big plates and it's
    converted to digital via a scanner.
    I thought it was something like this:

    http://www.cfht.hawaii.edu/HawaiianStarlight/

    A true, 338 megapixel camera set-up.


    Taking advantage of the rapid evolution of optical electronic
    detectors (CCDs) over the past two decades, CFHT is now able to cover
    most of its useful field of view with a detector 40 times more
    sensitive than the photographic plates! The MegaPrime imager which
    includes the MegaCam camera, a mosaic of forty individual CCD
    detectors, is the largest close-packed array in use in the world today
    (~18,400 x 18,400 pixels).
     
    RichA, Jan 1, 2005
    #5
  6. RichA

    RichA Guest

    I should have also said, objects no more than 30 feet away don't look
    as good as close-up shots in terms of subjective sharpness either.
    At 30ft, there should be no heat-wave problems and definitely no
    atmospheric extinction or "blue scattering" caused by oxygen
    molecules. I think possibly another reason for this is dynamic range
    of CCDs. With macro shots, you can control the lighting to maximize
    it, but you generally can't with long distance shots so you end up
    with blocky highlights (still!) residual chromatic aberration, etc,
    and both serve to kill details. What people generally don't
    understand about chromatic aberration is that it isn't just an
    "light-dark" edge problem; The defocussed blue and red light is
    suffused over the entire image, supressing contrast.
    -Rich
     
    RichA, Jan 1, 2005
    #6
  7. RichA

    John Francis Guest

    There are several Gigipixel image projects being discussed at various places on the 'net.
    One can be found at http://tawbaware.com ; another one is being done at a University
    in, IIRC, Copenhagen.
     
    John Francis, Jan 1, 2005
    #7
  8. RichA

    Frank ess Guest

    Delft, too.
     
    Frank ess, Jan 1, 2005
    #8
  9. RichA

    Alan Browne Guest

    Macro shots in particular show fine detail to a degree that we don't commonly
    see, so when we do see it, it is a fresh and often amazing experience. As a
    macro shot (typicaly 1:1) is of detail of an object the size of the image
    sensor, it is much finer than our daily experience. So the shot is perceived to
    be highly detailed.

    On a 'distant shot' there is less specific detail to look at so we don't 'see'
    the sharpnees in it.
    Atmospherics (convection, particulates) also soften the image a little to a lot,
    conditions depending.

    Cheers,
    Alan
     
    Alan Browne, Jan 1, 2005
    #9
  10. That has to do with the absolute resolution limit a sensor poses on
    fine detail. The sensor cannot reliably resolve projected detail
    that's smaller than 2 pixels. Landscapes, or any subject at a distance
    for that matter, will result in a very small magnification factor and
    thus collide with the limitations of regularly sampled imaging. The
    only solution (within the scope of this forum) is a higher resolution
    sensor that still looks sharp at the intended output magnification (or
    one can output at a smaller size). Stitching panoramas will
    effectively simulate a larger sensor, thus requiring less output
    magnification, but it has other limitations.

    Bart
     
    Bart van der Wolf, Jan 1, 2005
    #10
  11. RichA

    Will D. Guest

    Which is why landscapes are still taken with large format cameras.
    Compared to a smaller format, it has what we instinctively regard as a
    "presence', because the detail we can see selectively when we view the
    scene is available in the photograph. Smaller format simply cannot do
    that sort of job.

    Having said that, however, the factors that favor the larger format are:
    1) Resolution capability of the recording medium. 2) Resolution
    capability of the optical train. These are also addressed by smaller
    formats with varying success.

    Large format lenses are almost always very simple optical designs that
    can be manufactured to much higher resolution capabilities than the more
    complex designs used in smaller format cameras. Even so, they only have
    to do < 50 lp/mm to exceed what is possible with most smaller format
    recording medium.

    Put a very fine grain film in a Leica (mount Leica on tip of huge
    granite monolith; watch nearby earthquake monitor and wait for absolute
    flat line; use radio controlled remote to trigger Leica at fast shutter
    speed to reduce atmospherics; etc), and see the difference in landscapes
    done with Leica optics. Noticeable!

    Do the same with Nikonax/Canolta with very expensive optics.
    Noticeable!

    Well, to be fair, observe above parantheticals with your own rig, and
    see the difference ;)

    Compare above to medium format and note differences. Does format win?
    Not always, but usually.

    Obtain Canon 1Ds(MkII), fit with choice "L" lens (mount as above).
    Compare to medium format and note differences. Does format win? Well,
    sometimes. Some pros are switching to above rig in place of generic
    medium format gear. Probably the (MkII) even more so. These bodies
    *demand* the very best glass to perform to spec, though; they're
    notorious for showing up flaws in anything less, including "L" glass.
    EF100-400 L zoom comes to mind...

    Bottom line: You want to do landscapes? Go to larger format cameras.

    Will D.
     
    Will D., Jan 1, 2005
    #11
  12. RichA

    RichA Guest

    That shot of his would make a great wall mural.
    -Rich
     
    RichA, Jan 1, 2005
    #12
  13. As a matter of fact - a normal wall in a room in your home is
    around 1 Gigapixel large if you print at 250 PPI. 2.5 meters
    times 5 meters is with this resolution 2 Gigapixel.

    So - 1-2 Gigapixels is an optimal resolution if you want
    a high resolution picture covering a wall.

    As a matter of more fact - exactly that was one of my dreams
    when I was younger. Long before digital photography. It
    was never really possible. Now it is! If you only can find
    someone that can print the beast.


    /Roland
     
    Roland Karlsson, Jan 2, 2005
    #13
  14. RichA

    John Francis Guest

    FedEx/Kinkos will charge you around $10 per square foot.
    You'll have to print it in strips, of course; think of it
    as ending up with rolls of rather special wallpaper.
     
    John Francis, Jan 2, 2005
    #14
  15. Thats a thought. Now ... hhmmm ... a square foot, that is
    approx 0.1 square meter I think. Now $10, that is approx.
    SEK 75 I think. and 5x2.5 meters is 12.5 square meters.

    12.5 x (75 / 0.1) ~ SEK 10000

    Hmmm ... a rather expensive wallpaper. The same
    amount of money as a DSLR.


    /Roland
     
    Roland Karlsson, Jan 2, 2005
    #15
  16. RichA

    Ryadia Guest

    I can print it Roland... Give it back to you in rolls of wallpaper, 600 mm
    wide!

    Doug
     
    Ryadia, Jan 2, 2005
    #16
  17. Tempting :)

    Can you give a better price than the $10 per sq foot?


    /Roland
     
    Roland Karlsson, Jan 3, 2005
    #17
  18. RichA

    Ryadia Guest

    Maybe... Is that US dollars you are talking or another currency?
    Do you want water soluble coated back or will you size it?
    Do you want vynal face or plain?
    If you intend to put it on the wall as opposed to mount it on a massive
    sheet of board, the paper I use is different. Let me know some specifics and
    I'll happily quote a price. The largest I've done to date is in 8 foot
    lengths of 2 foot wide. The paper has to be trimmed to remove the 8mm wide
    strip where nothing is printed. This is where most people get into trouble
    because it has to be neat for the length of the paper to butt up against the
    next drop. Take it off line too, eh?

    Doug
     
    Ryadia, Jan 3, 2005
    #18
  19. As I said - Tempting.

    It is not all that probable that I will do it now though.

    The Bryce picture is fantastic - but my plan was to do one
    myself - and I don't have any :)

    Your information would be very appreciated though.
    I'll mail you and ask.


    /Roland
     
    Roland Karlsson, Jan 3, 2005
    #19
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