Digital Mosaics: Surpassing Large Format Film Images

Discussion in 'Digital Photography' started by Roger N. Clark (change username to rnclark), Aug 26, 2006.

  1. Hi.
    I have been doing large format photography for going on 2 decades.
    I have also been doing wildlife photography, first with 35mm then
    digital. Thus, I often carry both digital wildlife and 4x5 gear
    on a hike (up to 70 pounds). That gets real tiring and limits
    my range (and, obviously, I'm getting older). I want an alternative
    without giving up anything ;-). I switched to a Toho 4x5 field camera
    (3 pounds) from heavier cameras several years ago, but it is still
    too much weight doing both wildlife with digital and scenics with
    4x5.

    Mosaicking many digital image frames has intrigued me for
    some time, and I have been experimenting with the methods,
    from field to computer processing. Like large format view cameras
    and methods, there is much to learn. But my experience so far
    is that digital mosaics can equal and surpass 4x5 drum scanned
    film in many applications, including large depth of field imaging
    requiring tilts on a view camera. And I can get images in the
    field faster and under conditions not suitable for large format
    photography (like wind).

    I've written up some of my experiences in this article and compare
    the digital results to drum scanned 4x5 film images:

    Large Digital Mosaics as a Substitute for Large Format Film
    http://www.clarkvision.com/photoinfo/large_mosaics

    Comments welcome.

    Roger Clark
    my photos at: http://www.clarkvision.com
     
    Roger N. Clark (change username to rnclark), Aug 26, 2006
    #1
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  2. On Sat, 26 Aug 2006 08:55:05 -0600, "Roger N. Clark (change username
    to rnclark)" <> wrote:

    >Hi.
    >I have been doing large format photography for going on 2 decades.
    >I have also been doing wildlife photography, first with 35mm then
    >digital. Thus, I often carry both digital wildlife and 4x5 gear
    >on a hike (up to 70 pounds). That gets real tiring and limits
    >my range (and, obviously, I'm getting older). I want an alternative
    >without giving up anything ;-). I switched to a Toho 4x5 field camera
    >(3 pounds) from heavier cameras several years ago, but it is still
    >too much weight doing both wildlife with digital and scenics with
    >4x5.
    >
    >Mosaicking many digital image frames has intrigued me for
    >some time, and I have been experimenting with the methods,
    >from field to computer processing. Like large format view cameras
    >and methods, there is much to learn. But my experience so far
    >is that digital mosaics can equal and surpass 4x5 drum scanned
    >film in many applications, including large depth of field imaging
    >requiring tilts on a view camera. And I can get images in the
    >field faster and under conditions not suitable for large format
    >photography (like wind).
    >
    >I've written up some of my experiences in this article and compare
    >the digital results to drum scanned 4x5 film images:
    >
    > Large Digital Mosaics as a Substitute for Large Format Film
    > http://www.clarkvision.com/photoinfo/large_mosaics
    >
    >Comments welcome.


    Spectacular.

    You mention problems with focus from frame to frame.

    Do you manually focus and lock exposure from frame to frame?


    >
    >Roger Clark
    >my photos at: http://www.clarkvision.com


    --

    Scott in Florida

    'The Land of the Free Thanks to the Brave'
     
    Scott in Florida, Aug 26, 2006
    #2
    1. Advertising

  3. Scott in Florida wrote:

    > On Sat, 26 Aug 2006 08:55:05 -0600, "Roger N. Clark (change username
    > to rnclark)" <> wrote:
    >
    >
    >>Hi.
    >>I have been doing large format photography for going on 2 decades.
    >>I have also been doing wildlife photography, first with 35mm then
    >>digital. Thus, I often carry both digital wildlife and 4x5 gear
    >>on a hike (up to 70 pounds). That gets real tiring and limits
    >>my range (and, obviously, I'm getting older). I want an alternative
    >>without giving up anything ;-). I switched to a Toho 4x5 field camera
    >>(3 pounds) from heavier cameras several years ago, but it is still
    >>too much weight doing both wildlife with digital and scenics with
    >>4x5.
    >>
    >>Mosaicking many digital image frames has intrigued me for
    >>some time, and I have been experimenting with the methods,

    >
    >>from field to computer processing. Like large format view cameras

    >
    >>and methods, there is much to learn. But my experience so far
    >>is that digital mosaics can equal and surpass 4x5 drum scanned
    >>film in many applications, including large depth of field imaging
    >>requiring tilts on a view camera. And I can get images in the
    >>field faster and under conditions not suitable for large format
    >>photography (like wind).
    >>
    >>I've written up some of my experiences in this article and compare
    >>the digital results to drum scanned 4x5 film images:
    >>
    >> Large Digital Mosaics as a Substitute for Large Format Film
    >> http://www.clarkvision.com/photoinfo/large_mosaics
    >>
    >>Comments welcome.

    >
    >
    > Spectacular.
    >
    > You mention problems with focus from frame to frame.
    >
    > Do you manually focus and lock exposure from frame to frame?


    Thanks Scott.

    I determine the best overall exposure then go to manual and keep
    f/stop and exposure constant for the entire sequence.

    I autofocus separately for each frame, usually using 1 focus
    point. In general I have no problems focusing.
    The issue is: have I set a small enough aperture
    to give enough depth of field so that when focus changes from
    frame to frame, there is not an area in poor focus in the final
    mosaic.

    Roger
     
    Roger N. Clark (change username to rnclark), Aug 26, 2006
    #3
  4. On Sat, 26 Aug 2006 11:26:29 -0600, "Roger N. Clark (change username
    to rnclark)" <> wrote:

    >Scott in Florida wrote:
    >
    >> On Sat, 26 Aug 2006 08:55:05 -0600, "Roger N. Clark (change username
    >> to rnclark)" <> wrote:
    >>
    >>
    >>>Hi.
    >>>I have been doing large format photography for going on 2 decades.
    >>>I have also been doing wildlife photography, first with 35mm then
    >>>digital. Thus, I often carry both digital wildlife and 4x5 gear
    >>>on a hike (up to 70 pounds). That gets real tiring and limits
    >>>my range (and, obviously, I'm getting older). I want an alternative
    >>>without giving up anything ;-). I switched to a Toho 4x5 field camera
    >>>(3 pounds) from heavier cameras several years ago, but it is still
    >>>too much weight doing both wildlife with digital and scenics with
    >>>4x5.
    >>>
    >>>Mosaicking many digital image frames has intrigued me for
    >>>some time, and I have been experimenting with the methods,

    >>
    >>>from field to computer processing. Like large format view cameras

    >>
    >>>and methods, there is much to learn. But my experience so far
    >>>is that digital mosaics can equal and surpass 4x5 drum scanned
    >>>film in many applications, including large depth of field imaging
    >>>requiring tilts on a view camera. And I can get images in the
    >>>field faster and under conditions not suitable for large format
    >>>photography (like wind).
    >>>
    >>>I've written up some of my experiences in this article and compare
    >>>the digital results to drum scanned 4x5 film images:
    >>>
    >>> Large Digital Mosaics as a Substitute for Large Format Film
    >>> http://www.clarkvision.com/photoinfo/large_mosaics
    >>>
    >>>Comments welcome.

    >>
    >>
    >> Spectacular.
    >>
    >> You mention problems with focus from frame to frame.
    >>
    >> Do you manually focus and lock exposure from frame to frame?

    >
    >Thanks Scott.
    >
    >I determine the best overall exposure then go to manual and keep
    >f/stop and exposure constant for the entire sequence.
    >
    >I autofocus separately for each frame, usually using 1 focus
    >point. In general I have no problems focusing.
    >The issue is: have I set a small enough aperture
    >to give enough depth of field so that when focus changes from
    >frame to frame, there is not an area in poor focus in the final
    >mosaic.
    >
    >Roger


    So your focus point can change frame to frame?

    Would it be worthwhile to pick a focus point and go back to manual
    focus?

    Can you notice much change in the images with different focus points?

    The reason I ask, is I am going to do one on a Light House in southern
    Maine (Nubble) my next trip up.


    --

    Scott in Florida

    'The Land of the Free Thanks to the Brave'
     
    Scott in Florida, Aug 26, 2006
    #4
  5. Roger N. Clark (change username to rnclark)

    Bill Funk Guest

    On Sat, 26 Aug 2006 11:26:29 -0600, "Roger N. Clark (change username
    to rnclark)" <> wrote:

    >Scott in Florida wrote:
    >
    >> On Sat, 26 Aug 2006 08:55:05 -0600, "Roger N. Clark (change username
    >> to rnclark)" <> wrote:
    >>
    >>
    >>>Hi.
    >>>I have been doing large format photography for going on 2 decades.
    >>>I have also been doing wildlife photography, first with 35mm then
    >>>digital. Thus, I often carry both digital wildlife and 4x5 gear
    >>>on a hike (up to 70 pounds). That gets real tiring and limits
    >>>my range (and, obviously, I'm getting older). I want an alternative
    >>>without giving up anything ;-). I switched to a Toho 4x5 field camera
    >>>(3 pounds) from heavier cameras several years ago, but it is still
    >>>too much weight doing both wildlife with digital and scenics with
    >>>4x5.
    >>>
    >>>Mosaicking many digital image frames has intrigued me for
    >>>some time, and I have been experimenting with the methods,

    >>
    >>>from field to computer processing. Like large format view cameras

    >>
    >>>and methods, there is much to learn. But my experience so far
    >>>is that digital mosaics can equal and surpass 4x5 drum scanned
    >>>film in many applications, including large depth of field imaging
    >>>requiring tilts on a view camera. And I can get images in the
    >>>field faster and under conditions not suitable for large format
    >>>photography (like wind).
    >>>
    >>>I've written up some of my experiences in this article and compare
    >>>the digital results to drum scanned 4x5 film images:
    >>>
    >>> Large Digital Mosaics as a Substitute for Large Format Film
    >>> http://www.clarkvision.com/photoinfo/large_mosaics
    >>>
    >>>Comments welcome.

    >>
    >>
    >> Spectacular.
    >>
    >> You mention problems with focus from frame to frame.
    >>
    >> Do you manually focus and lock exposure from frame to frame?

    >
    >Thanks Scott.
    >
    >I determine the best overall exposure then go to manual and keep
    >f/stop and exposure constant for the entire sequence.
    >
    >I autofocus separately for each frame, usually using 1 focus
    >point. In general I have no problems focusing.
    >The issue is: have I set a small enough aperture
    >to give enough depth of field so that when focus changes from
    >frame to frame, there is not an area in poor focus in the final
    >mosaic.
    >
    >Roger


    I just did a presentation on panos/mosaics for a digital photo SIG
    this week, and I used Autostitch.
    I covered setting the aperture for a wide depth of field (if that's
    what's wanted), which seems like a good thing! :)
    I also covered the need to be careful about lens selection. When I
    used my EF 17-40mm lens, since it's rectilinear, Autostitch was able
    to make the resulting pano look good by rotating the different
    individual images to get a non-keystoned final image.
    http://pippina.us/images/glendale 1.jpg
    But, using my Panny FX01, which doesn't have a rectilinear lens, there
    are problems with the pincushioning at wide angles; the obvious
    solution is to use a longer focal length, and take more shots to feed
    to Autostitch.
    http://pippina.us/images/glendale 1.jpg
    :)
    --
    Bill Funk
    replace "g" with "a"
     
    Bill Funk, Aug 26, 2006
    #5
  6. Roger N. Clark (change username to rnclark) wrote:
    []
    > I've written up some of my experiences in this article and compare
    > the digital results to drum scanned 4x5 film images:
    >
    > Large Digital Mosaics as a Substitute for Large Format Film
    > http://www.clarkvision.com/photoinfo/large_mosaics
    >
    > Comments welcome.
    >
    > Roger Clark
    > my photos at: http://www.clarkvision.com


    Many thanks for writing that up, Roger. A fascinating read. You will
    doubtless be looking for ways to speed the post-processing.

    And I thought it was just me who was fussy about weight!

    Cheers,
    David
     
    David J Taylor, Aug 26, 2006
    #6
  7. Roger N. Clark (change username to rnclark)

    ASAAR Guest

    On Sat, 26 Aug 2006 19:48:54 GMT, David J Taylor wrote:

    >> Large Digital Mosaics as a Substitute for Large Format Film
    >> http://www.clarkvision.com/photoinfo/large_mosaics
    >>
    >> Comments welcome.
    >>
    >> Roger Clark
    >> my photos at: http://www.clarkvision.com

    >
    > Many thanks for writing that up, Roger. A fascinating read. You will
    > doubtless be looking for ways to speed the post-processing.
    >
    > And I thought it was just me who was fussy about weight!


    Anxiously awaiting

    "Large Digital Mosaics as a Substitute for Large DSLRs".

    :)
     
    ASAAR, Aug 26, 2006
    #7
  8. ASAAR wrote:
    > On Sat, 26 Aug 2006 19:48:54 GMT, David J Taylor wrote:
    >
    >>> Large Digital Mosaics as a Substitute for Large Format Film
    >>> http://www.clarkvision.com/photoinfo/large_mosaics
    >>>
    >>> Comments welcome.
    >>>
    >>> Roger Clark
    >>> my photos at: http://www.clarkvision.com

    >>
    >> Many thanks for writing that up, Roger. A fascinating read. You
    >> will doubtless be looking for ways to speed the post-processing.
    >>
    >> And I thought it was just me who was fussy about weight!

    >
    > Anxiously awaiting
    >
    > "Large Digital Mosaics as a Substitute for Large DSLRs".
    >
    > :)


    I'm waiting to hear how you can do even better it with an array of Fuji
    F30s!

    David
     
    David J Taylor, Aug 26, 2006
    #8
  9. "Roger N. Clark (change username to rnclark)" <>
    wrote in message news:...
    SNIP
    > I've written up some of my experiences in this article and compare
    > the digital results to drum scanned 4x5 film images:
    >
    > Large Digital Mosaics as a Substitute for Large Format Film
    > http://www.clarkvision.com/photoinfo/large_mosaics
    >
    > Comments welcome.


    Congratulations on a successful, and beautiful, stitched image.
    It inspires to experiment more with variable focus distances. The
    potential magnification differences (esp. at shorter distances) can be
    addressed in the stitching optimizer with the additional per image
    optimization of the focal length parameter.

    To address some of the points you mentioned in your write-up:

    - As for the Pros, I agree with the points mentioned, in particular
    about the lower restrictions for DOF, because the full image doesn't
    have to be in acceptable focus, but 'only' the partial frame inside
    the final overlap does. The resulting faster shutterspeed helps in
    reducing subject (wind)motion.

    - As for the Cons, I think the depth of field matching could
    (depending on subject) be significantly helped by using a Tilt and
    Shift lens. I often use the T/S-E 45mm f/2.8 for stitched images. It
    would also allow to reduce the number of images, which benefits the
    amount of post-processing and reduces the risk of changing light
    conditions. Alternatively one could consider an additional program
    like Helicon Focus
    <http://www.heliconfocus.com/pages/focus_overview.html>.

    - The Photoshop layers can potentially be skipped for the most part,
    when you use SmartBlend. It'll adjust for small brightness
    differences, and it does a remarkable job of blending between images
    with movement (ghosting), all on full automatic. The downside is that
    it takes its time doing it, but that's not too much of an issue if you
    let it run in otherwise idle time.

    --
    Bart
     
    Bart van der Wolf, Aug 26, 2006
    #9
  10. Roger N. Clark (change username to rnclark)

    ASAAR Guest

    On Sat, 26 Aug 2006 20:02:08 GMT, David J Taylor wrote:

    >> "Large Digital Mosaics as a Substitute for Large DSLRs".
    >>
    >> :)

    >
    > I'm waiting to hear how you can do even better it with an array of Fuji
    > F30s!


    That's kinda sleazy, coming as it does from he who finds even more
    ways to push and plug Panasonics than the most rabid Canonistas do
    their precious Canons. FWIW, I've said that those F10/F11/F30
    Fujis, even though they're excellent low light cameras, aren't my
    choice for a number of reasons. Not only that, I've chided kinga
    several times for his stupidly hyperbolic F30 posts. Are you trying
    to sound like a little boy?
     
    ASAAR, Aug 26, 2006
    #10
  11. "ASAAR" <> wrote in message
    news:...
    > On Sat, 26 Aug 2006 19:48:54 GMT, David J Taylor wrote:
    >
    >>> Large Digital Mosaics as a Substitute for Large Format Film
    >>> http://www.clarkvision.com/photoinfo/large_mosaics
    >>>
    >>> Comments welcome.
    >>>
    >>> Roger Clark
    >>> my photos at: http://www.clarkvision.com

    >>
    >> Many thanks for writing that up, Roger. A fascinating read. You
    >> will
    >> doubtless be looking for ways to speed the post-processing.
    >>
    >> And I thought it was just me who was fussy about weight!

    >
    > Anxiously awaiting
    >
    > "Large Digital Mosaics as a Substitute for Large DSLRs".


    Been there, done that (with a Powershot G3),
    <http://www.xs4all.nl/~bvdwolf/main/downloads/BerlinerDom.jpg> 6
    images at 1/3rd of original pixel dimensions, and still moved on to a
    DSLR ... ;-)

    --
    Bart
     
    Bart van der Wolf, Aug 26, 2006
    #11
  12. Bart van der Wolf wrote:

    >
    > "ASAAR" <> wrote in message
    > news:...
    >
    >> On Sat, 26 Aug 2006 19:48:54 GMT, David J Taylor wrote:
    >>
    >>>> Large Digital Mosaics as a Substitute for Large Format Film
    >>>> http://www.clarkvision.com/photoinfo/large_mosaics
    >>>>
    >>>> Comments welcome.
    >>>>
    >>>> Roger Clark
    >>>> my photos at: http://www.clarkvision.com
    >>>
    >>>
    >>> Many thanks for writing that up, Roger. A fascinating read. You will
    >>> doubtless be looking for ways to speed the post-processing.
    >>>
    >>> And I thought it was just me who was fussy about weight!

    >>
    >>
    >> Anxiously awaiting
    >>
    >> "Large Digital Mosaics as a Substitute for Large DSLRs".

    >
    >
    > Been there, done that (with a Powershot G3),
    > <http://www.xs4all.nl/~bvdwolf/main/downloads/BerlinerDom.jpg> 6 images
    > at 1/3rd of original pixel dimensions, and still moved on to a DSLR ... ;-)
    >

    Yep,
    You can surpass the pixel count easily, but it is harder
    (though not impossible) to surpass the photon count and low noise.
    To surpass the photon count, one would need perfectly still
    scenes, and average several frames for each mosaic position.

    Roger
     
    Roger N. Clark (change username to rnclark), Aug 26, 2006
    #12
  13. Scott in Florida wrote:

    > On Sat, 26 Aug 2006 11:26:29 -0600, "Roger N. Clark (change username
    > to rnclark)" <> wrote:
    >
    >
    >>Scott in Florida wrote:
    >>
    >>
    >>>On Sat, 26 Aug 2006 08:55:05 -0600, "Roger N. Clark (change username
    >>>to rnclark)" <> wrote:
    >>>
    >>>
    >>>
    >>>>Hi.
    >>>>I have been doing large format photography for going on 2 decades.
    >>>>I have also been doing wildlife photography, first with 35mm then
    >>>>digital. Thus, I often carry both digital wildlife and 4x5 gear
    >>>>on a hike (up to 70 pounds). That gets real tiring and limits
    >>>>my range (and, obviously, I'm getting older). I want an alternative
    >>>>without giving up anything ;-). I switched to a Toho 4x5 field camera
    >>>>(3 pounds) from heavier cameras several years ago, but it is still
    >>>>too much weight doing both wildlife with digital and scenics with
    >>>>4x5.
    >>>>
    >>>>Mosaicking many digital image frames has intrigued me for
    >>>>some time, and I have been experimenting with the methods,
    >>>
    >>>>from field to computer processing. Like large format view cameras
    >>>
    >>>
    >>>>and methods, there is much to learn. But my experience so far
    >>>>is that digital mosaics can equal and surpass 4x5 drum scanned
    >>>>film in many applications, including large depth of field imaging
    >>>>requiring tilts on a view camera. And I can get images in the
    >>>>field faster and under conditions not suitable for large format
    >>>>photography (like wind).
    >>>>
    >>>>I've written up some of my experiences in this article and compare
    >>>>the digital results to drum scanned 4x5 film images:
    >>>>
    >>>> Large Digital Mosaics as a Substitute for Large Format Film
    >>>> http://www.clarkvision.com/photoinfo/large_mosaics
    >>>>
    >>>>Comments welcome.
    >>>
    >>>
    >>>Spectacular.
    >>>
    >>>You mention problems with focus from frame to frame.
    >>>
    >>>Do you manually focus and lock exposure from frame to frame?

    >>
    >>Thanks Scott.
    >>
    >>I determine the best overall exposure then go to manual and keep
    >>f/stop and exposure constant for the entire sequence.
    >>
    >>I autofocus separately for each frame, usually using 1 focus
    >>point. In general I have no problems focusing.
    >>The issue is: have I set a small enough aperture
    >>to give enough depth of field so that when focus changes from
    >>frame to frame, there is not an area in poor focus in the final
    >>mosaic.
    >>
    >>Roger

    >
    >
    > So your focus point can change frame to frame?


    Yes.
    >
    > Would it be worthwhile to pick a focus point and go back to manual
    > focus?


    If you have adequate depth of field, yes. The advantage of
    changing the focus point is to get good local depth of
    field without having to go to all extremes in the image.
    >
    > Can you notice much change in the images with different focus points?


    If your depth of field is adequate, the change is negligible.

    > The reason I ask, is I am going to do one on a Light House in southern
    > Maine (Nubble) my next trip up.


    Try it. Use several apertures and see which works best.

    Roger
     
    Roger N. Clark (change username to rnclark), Aug 26, 2006
    #13
  14. Bill Funk wrote:

    > I just did a presentation on panos/mosaics for a digital photo SIG
    > this week, and I used Autostitch.
    > I covered setting the aperture for a wide depth of field (if that's
    > what's wanted), which seems like a good thing! :)
    > I also covered the need to be careful about lens selection. When I
    > used my EF 17-40mm lens, since it's rectilinear, Autostitch was able
    > to make the resulting pano look good by rotating the different
    > individual images to get a non-keystoned final image.
    > http://pippina.us/images/glendale 1.jpg
    > But, using my Panny FX01, which doesn't have a rectilinear lens, there
    > are problems with the pincushioning at wide angles; the obvious
    > solution is to use a longer focal length, and take more shots to feed
    > to Autostitch.
    > http://pippina.us/images/glendale 1.jpg
    > :)


    Bill,
    Aren't these the same images? Looks like the same link to me.

    Roger
     
    Roger N. Clark (change username to rnclark), Aug 26, 2006
    #14
  15. On Sat, 26 Aug 2006 15:58:23 -0600, Roger N. Clark (change username to rnclark) <> wrote:
    > Bart van der Wolf wrote:
    >
    >>
    >> "ASAAR" <> wrote in message
    >>> Anxiously awaiting
    >>>
    >>> "Large Digital Mosaics as a Substitute for Large DSLRs".

    >>
    >> Been there, done that (with a Powershot G3),
    >> <http://www.xs4all.nl/~bvdwolf/main/downloads/BerlinerDom.jpg> 6 images
    >> at 1/3rd of original pixel dimensions, and still moved on to a DSLR ... ;-)
    >>

    > Yep,
    > You can surpass the pixel count easily, but it is harder
    > (though not impossible) to surpass the photon count and low noise.
    > To surpass the photon count, one would need perfectly still
    > scenes, and average several frames for each mosaic position.


    You could get better photon count on a small-sensor camera by taking
    enough frames to get a mosaic at 2x or 3x the desired resolution, and
    then use binning to get down to the final resolution.

    It would probably make sense to do the binning before the stitching, to
    keep the computational load down.

    -dms
     
    Daniel Silevitch, Aug 26, 2006
    #15
  16. Roger N. Clark (change username to rnclark)

    ASAAR Guest

    On Sat, 26 Aug 2006 23:25:52 +0200, Bart van der Wolf wrote:

    >> Anxiously awaiting
    >>
    >> "Large Digital Mosaics as a Substitute for Large DSLRs".

    >
    > Been there, done that (with a Powershot G3),
    > <http://www.xs4all.nl/~bvdwolf/main/downloads/BerlinerDom.jpg> 6
    > images at 1/3rd of original pixel dimensions, and still moved on to a
    > DSLR ... ;-)


    I assume that you didn't purchase the DSLR just to do panoramics,
    but took advantage of their superior panoramic advantages, compared
    to large format film. If DSLRs didn't exist, smaller dcams could
    take their place. They do take more time and effort (and frames)
    compared with DSLRs, but they do allow anyone to take panoramics
    even if they don't have sufficient resources to own a DSLR and one
    or more lenses, each one probably more expensive than the P&S.
    While my old Powershot S10 has a panoramic mode, your G3 and any
    recent DSLR should be far superior for that purpose. But there are
    a good number of high resolution non-DSLRs that have excellent
    lenses and that should also be capable of producing very large, high
    quality panoramics nearly as easily as DSLRs.
     
    ASAAR, Aug 26, 2006
    #16
  17. Bart van der Wolf wrote:

    >
    > "Roger N. Clark (change username to rnclark)" <> wrote
    > in message news:...
    > SNIP
    >
    >> I've written up some of my experiences in this article and compare
    >> the digital results to drum scanned 4x5 film images:
    >>
    >> Large Digital Mosaics as a Substitute for Large Format Film
    >> http://www.clarkvision.com/photoinfo/large_mosaics
    >>
    >> Comments welcome.

    >
    >
    > Congratulations on a successful, and beautiful, stitched image.
    > It inspires to experiment more with variable focus distances. The
    > potential magnification differences (esp. at shorter distances) can be
    > addressed in the stitching optimizer with the additional per image
    > optimization of the focal length parameter.
    >
    > To address some of the points you mentioned in your write-up:
    >
    > - As for the Pros, I agree with the points mentioned, in particular
    > about the lower restrictions for DOF, because the full image doesn't
    > have to be in acceptable focus, but 'only' the partial frame inside the
    > final overlap does. The resulting faster shutterspeed helps in reducing
    > subject (wind)motion.
    >
    > - As for the Cons, I think the depth of field matching could (depending
    > on subject) be significantly helped by using a Tilt and Shift lens. I
    > often use the T/S-E 45mm f/2.8 for stitched images. It would also allow
    > to reduce the number of images, which benefits the amount of
    > post-processing and reduces the risk of changing light conditions.
    > Alternatively one could consider an additional program like Helicon
    > Focus <http://www.heliconfocus.com/pages/focus_overview.html>.


    Bart,
    Thanks.

    Yes, I agree. PTGui has advanced modes for working with tilt-shift lenses.
    I do not have one, but I may rethink that. One question is if
    you set the tilt for a local frame in the foreground, what happens
    when you raise up to the horizon where you would not want tilt
    in that frame?

    > - The Photoshop layers can potentially be skipped for the most part,
    > when you use SmartBlend. It'll adjust for small brightness differences,
    > and it does a remarkable job of blending between images with movement
    > (ghosting), all on full automatic. The downside is that it takes its
    > time doing it, but that's not too much of an issue if you let it run in
    > otherwise idle time.


    I'll have to look at that.

    Roger
     
    Roger N. Clark (change username to rnclark), Aug 26, 2006
    #17
  18. Daniel Silevitch wrote:

    > On Sat, 26 Aug 2006 15:58:23 -0600, Roger N. Clark (change username to rnclark) <> wrote:
    >
    >>Bart van der Wolf wrote:
    >>
    >>
    >>>"ASAAR" <> wrote in message
    >>>
    >>>> Anxiously awaiting
    >>>>
    >>>>"Large Digital Mosaics as a Substitute for Large DSLRs".
    >>>
    >>>Been there, done that (with a Powershot G3),
    >>><http://www.xs4all.nl/~bvdwolf/main/downloads/BerlinerDom.jpg> 6 images
    >>>at 1/3rd of original pixel dimensions, and still moved on to a DSLR ... ;-)
    >>>

    >>
    >>Yep,
    >>You can surpass the pixel count easily, but it is harder
    >>(though not impossible) to surpass the photon count and low noise.
    >>To surpass the photon count, one would need perfectly still
    >>scenes, and average several frames for each mosaic position.

    >
    >
    > You could get better photon count on a small-sensor camera by taking
    > enough frames to get a mosaic at 2x or 3x the desired resolution, and
    > then use binning to get down to the final resolution.
    >
    > It would probably make sense to do the binning before the stitching, to
    > keep the computational load down.


    Yes, good point. But it becomes difficult rather quickly.
    The 1D Mark II with its 8+ micron pixels holds up to
    80,000 electrons/pixel. A small pixel camera may hold less
    than 15,000, or over 5x less. One would need more than
    5 frames of small sensor size to match the large sensor
    (assuming each sensor had the same pixel count). But that
    doesn't include overlap. A mosaic needs overlap, so instead of
    a 5 array mosaic, you would need to frame more like 8 or 9 to
    match a single large sensor image.

    Then if the large camera mosaic did 50 frames for an image
    (including overlap), the small sensor would need more than
    400 frames to get the same spatial resolution and photon count
    per pixel. But it can be done!

    Roger
     
    Roger N. Clark (change username to rnclark), Aug 26, 2006
    #18
  19. Roger N. Clark (change username to rnclark)

    ASAAR Guest

    On Sat, 26 Aug 2006 16:29:57 -0600, Roger N. Clark (change username
    to rnclark), phamous photon parser wrote:

    > Yes, good point. But it becomes difficult rather quickly.
    > The 1D Mark II with its 8+ micron pixels holds up to
    > 80,000 electrons/pixel. A small pixel camera may hold less
    > than 15,000, or over 5x less. One would need more than
    > 5 frames of small sensor size to match the large sensor
    > (assuming each sensor had the same pixel count). But that
    > doesn't include overlap. A mosaic needs overlap, so instead of
    > a 5 array mosaic, you would need to frame more like 8 or 9 to
    > match a single large sensor image.
    >
    > Then if the large camera mosaic did 50 frames for an image
    > (including overlap), the small sensor would need more than
    > 400 frames to get the same spatial resolution and photon count
    > per pixel. But it can be done!


    But then since the large camera is producing a mosaic, with its
    own overlapped images, instead of the single image you introduced to
    provide a very short lived advantage that never should have been
    made, it quickly reverts back to nearly a 5:1 ratio instead of the
    8:1 or 9:1 ratio you seem to have left for us to consider. I don't
    think anyone suggested that only a single DSLR frame would be used.
    In fact it was your own paper and the title of this thread that
    suggested a DSLR mosaic. Others (and we know who they are) often
    resort to misleading statements and slight of hand to bolster their
    biases. It's disappointing, given your more scientific approach, to
    see you also engaging in suggestive, but misleading "spin",
    especially when it's not needed to prove your point.
     
    ASAAR, Aug 27, 2006
    #19
  20. On Sat, 26 Aug 2006 16:29:57 -0600, Roger N. Clark (change username to rnclark) <> wrote:
    > Daniel Silevitch wrote:
    >>
    >> You could get better photon count on a small-sensor camera by taking
    >> enough frames to get a mosaic at 2x or 3x the desired resolution, and
    >> then use binning to get down to the final resolution.
    >>
    >> It would probably make sense to do the binning before the stitching, to
    >> keep the computational load down.

    >
    > Yes, good point. But it becomes difficult rather quickly.
    > The 1D Mark II with its 8+ micron pixels holds up to
    > 80,000 electrons/pixel. A small pixel camera may hold less
    > than 15,000, or over 5x less. One would need more than
    > 5 frames of small sensor size to match the large sensor
    > (assuming each sensor had the same pixel count). But that
    > doesn't include overlap. A mosaic needs overlap, so instead of
    > a 5 array mosaic, you would need to frame more like 8 or 9 to
    > match a single large sensor image.
    >
    > Then if the large camera mosaic did 50 frames for an image
    > (including overlap), the small sensor would need more than
    > 400 frames to get the same spatial resolution and photon count
    > per pixel. But it can be done!


    But you need the same overlap fraction on the DSLR. You're applying the
    overlap fraction for the small-sensor camera twice, which is the
    equivalent of saying "Take a 9-frame mosaic, stitch it and bin it back
    down; now take a bunch of these and stitch them together to make the
    final mosaic". In reality, anybody trying to make a small-sensor
    high-photon-count image would do it in a single pass, but with smaller
    angular coverage for each frame than the DSLR user would use.

    So, it would be 250ish frames for the small camera, not 400ish.

    -dms
     
    Daniel Silevitch, Aug 27, 2006
    #20
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