Another megapixel experement

Discussion in 'Digital Photography' started by JohnR66, Nov 23, 2006.

  1. JohnR66

    JohnR66 Guest

    I just picked up a Digital Rebel Xti. I always test cameras out before
    putting them to use. I photographed a test chart with each camera to see the
    progression of resolution with the megapixel count. Here's the results.
    These were 200% pixel enlarged for clarity in viewing:

    http://home.att.net/~jriegle/restest.jpg

    Line pair set resolved:

    Fujifilm A330 3mp: 6

    Canon A610 5mp: 8

    Canon Digital Rebel: 9

    Canon Digital Rebel XTi: 11

    Finally with the A330 in the same position as the first shot, I zoomed its
    3x lens all the way. It shows that zooming a lower resolution camera in is
    better than trying to crop a high res camera image.

    My main concern was seeing the difference in the original Rebel vs. the new
    one. There is a fair bit of extra resolution in the XTi. This will benefit
    people making larger prints.

    John
    JohnR66, Nov 23, 2006
    #1
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  2. JohnR66

    timeOday Guest

    JohnR66 wrote:

    > Finally with the A330 in the same position as the first shot, I zoomed its
    > 3x lens all the way. It shows that zooming a lower resolution camera in is
    > better than trying to crop a high res camera image.


    I'm confused about this. Are most of your shots (other than this one)
    all taken at an equivalent focal length, i.e. framed (not cropped)
    identically?
    timeOday, Nov 23, 2006
    #2
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  3. JohnR66

    JohnR66 Guest

    "timeOday" <> wrote in message
    news:...
    > JohnR66 wrote:
    >
    >> Finally with the A330 in the same position as the first shot, I zoomed
    >> its 3x lens all the way. It shows that zooming a lower resolution camera
    >> in is better than trying to crop a high res camera image.

    >
    > I'm confused about this. Are most of your shots (other than this one) all
    > taken at an equivalent focal length, i.e. framed (not cropped)
    > identically?


    The charts in the image are just a tiny patch on a big 36x24 inch test
    chart. The cameras were set up on a tripod and moved so that the edge of the
    chart matched with the edge of the image. Since the compacts aspect ratio
    don't match the chart's, these cameras were matched with the vertical edge
    of the chart (this does give a slight resolution advantage to the dSLRs).
    With the zoomed shot at the bottom, the A330 was set at wide angle and
    matched to the vertical edge of the chart and then it's 3x lens zoomed in.

    A camera store sales droid told me once that if I had a took two cameras,
    one 3mp and the other 9mp, put a 18-55 zoom on them and zoomed the 3mp
    camera to 55mm and left the 9mp camera at 18mm, then cropped the 9mp image
    to show the same area the 3mp camera made, I should see the same detail. I
    knew this was bull because the megapixle count of the 9mp camera would have
    to be squared of the original camera, or 27mp.

    This also shows why the difference of a few megapixels doesn't translate
    into a big increase in image detail. The difference between the 6 and 8mp
    Rebels was not enough to make me want to upgrade. The difference between 8
    and 10 is even less, however, the difference between 6 and 10 is small but
    significant enough to want to make me want to upgrade. I like to make large
    prints of my photos and the extra bit of detail from 10mp is nice.

    For me at least, the megapixel race is over. A 10mp APS sized sensor is
    going to need good glass to get the resolution needed to make good pictures.
    My next step would be full frame, but I need to get 3 years out of my XTi
    investmant.
    John

    John
    JohnR66, Nov 23, 2006
    #3
  4. JohnR66

    timeOday Guest

    JohnR66 wrote:
    > "timeOday" <> wrote in message
    > news:...
    >
    >>JohnR66 wrote:
    >>
    >>
    >>>Finally with the A330 in the same position as the first shot, I zoomed
    >>>its 3x lens all the way. It shows that zooming a lower resolution camera
    >>>in is better than trying to crop a high res camera image.

    >>
    >>I'm confused about this. Are most of your shots (other than this one) all
    >>taken at an equivalent focal length, i.e. framed (not cropped)
    >>identically?

    >
    >
    > The charts in the image are just a tiny patch on a big 36x24 inch test
    > chart. The cameras were set up on a tripod and moved so that the edge of the
    > chart matched with the edge of the image. Since the compacts aspect ratio
    > don't match the chart's, these cameras were matched with the vertical edge
    > of the chart (this does give a slight resolution advantage to the dSLRs).
    > With the zoomed shot at the bottom, the A330 was set at wide angle and
    > matched to the vertical edge of the chart and then it's 3x lens zoomed in.


    Another thing to think about is that you may not get the best images at
    wide angle. When my camera is zoomed all the way out the images are
    noticeably soft near the edges, so I don't do that when I can easily
    scoot back a few feet and zoom in to 80mm eqiv or so.

    > A camera store sales droid told me once that if I had a took two cameras,
    > one 3mp and the other 9mp, put a 18-55 zoom on them and zoomed the 3mp
    > camera to 55mm and left the 9mp camera at 18mm, then cropped the 9mp image
    > to show the same area the 3mp camera made, I should see the same detail. I
    > knew this was bull because the megapixle count of the 9mp camera would have
    > to be squared of the original camera, or 27mp.


    Yeah. Plus, unless the 9mp camera has a much bigger sensor, it will
    have smaller pixels than the 3mp, so each pixel would have lower quality
    if all else were equal. (But it's probably not, since nobody would put
    a decent lens on a 3MP sensor now.)
    timeOday, Nov 23, 2006
    #4
  5. JohnR66

    frederick Guest

    JohnR66 wrote:

    > For me at least, the megapixel race is over. A 10mp APS sized sensor is
    > going to need good glass to get the resolution needed to make good pictures.
    > My next step would be full frame, but I need to get 3 years out of my XTi
    > investmant.


    From what I've seen, I'd agree with that. Your samples show ~20%
    increase in linear resolution - about what you could expect in ideal
    conditions from a 6 to 10mp increase in pixel count. The theoretical
    ~30% isn't achieved because the optics don't perform at 100% efficiency.
    But, I bet the 400d is nicer to use than the 300d, and that will
    probably count more than the increased pixel count.
    frederick, Nov 23, 2006
    #5
  6. JohnR66

    Bill Funk Guest

    On Fri, 24 Nov 2006 10:22:37 +1300, frederick <> wrote:

    >JohnR66 wrote:
    >
    >> For me at least, the megapixel race is over. A 10mp APS sized sensor is
    >> going to need good glass to get the resolution needed to make good pictures.
    >> My next step would be full frame, but I need to get 3 years out of my XTi
    >> investmant.

    >
    > From what I've seen, I'd agree with that. Your samples show ~20%
    >increase in linear resolution - about what you could expect in ideal
    >conditions from a 6 to 10mp increase in pixel count. The theoretical
    >~30% isn't achieved because the optics don't perform at 100% efficiency.
    >But, I bet the 400d is nicer to use than the 300d, and that will
    >probably count more than the increased pixel count.


    I'm sure for a lot of people, the 400D is nicer to use than the 300D.
    But...
    Recently a friend was with me in a Wal Mart where they had a 400D
    (Rebel XTi) on display, with the kit lens. My friend has a D60, I have
    a 30D. We picked up the XTi, and were amazed at the small size and
    lite weight. For us, it was totally unacceptable, though. While it
    balanced well with the kit lens, if (what could be considered) a
    better lens (for example, an EF 28-135 IS lens) were put on it, we
    both felt it would be out of balance. Maybe our experience with
    heavier camera bodies has something to do with that.
    For me, the small size makes it a non-starter, too.
    Ergonomics is more important (and different) for some people.
    --
    Bill Funk
    replace "g" with "a"
    Bill Funk, Nov 23, 2006
    #6
  7. JohnR66

    ASAAR Guest

    On Thu, 23 Nov 2006 15:02:51 GMT, JohnR66 wrote:

    > A camera store sales droid told me once that if I had a took two cameras,
    > one 3mp and the other 9mp, put a 18-55 zoom on them and zoomed the 3mp
    > camera to 55mm and left the 9mp camera at 18mm, then cropped the 9mp image
    > to show the same area the 3mp camera made, I should see the same detail. I
    > knew this was bull because the megapixle count of the 9mp camera would have
    > to be squared of the original camera, or 27mp.


    I'm caught in a megapickle, as the square root of 27 is about 5.2,
    so an equation or two might help to follow your logic. Dangerously
    assuming that both cameras used sensors having the same size, with a
    3:1 zoom ratio the 9mp camera at 18mm fl would have captured what
    the 3mp camera did at 55mm in a cropped section containing only
    1/9th of its 9 megapixels. Oops, I guess that you did get it right,
    since if the sensor was 27mp, 1/9th of its (really tiny, cruddy)
    pixels would match the other sensor's 3mp. So as far as what you
    heard in the store is concerned, the sales droid's logic is null and
    void. :)


    > For me at least, the megapixel race is over. A 10mp APS sized sensor
    > is going to need good glass to get the resolution needed to make good
    > pictures. My next step would be full frame, but I need to get 3 years
    > out of my XTi investmant.


    Until then you can do as some others have. Whenever they want
    really high resolution images, subject permitting, they create very
    high resolution stitched panoramics. This may be less convenient
    than using a full frame camera, but it has a couple of advantages,
    including much higher potential resolution as well as a much wider
    angle, more than offsetting the FF's inherent wide angle advantage
    from a particular lens if only a single frame is used.
    ASAAR, Nov 24, 2006
    #7
  8. JohnR66

    Scott W Guest

    ASAAR wrote:
    > On Thu, 23 Nov 2006 15:02:51 GMT, JohnR66 wrote:
    >
    > > A camera store sales droid told me once that if I had a took two cameras,
    > > one 3mp and the other 9mp, put a 18-55 zoom on them and zoomed the 3mp
    > > camera to 55mm and left the 9mp camera at 18mm, then cropped the 9mp image
    > > to show the same area the 3mp camera made, I should see the same detail. I
    > > knew this was bull because the megapixle count of the 9mp camera would have
    > > to be squared of the original camera, or 27mp.

    >
    > I'm caught in a megapickle, as the square root of 27 is about 5.2,
    > so an equation or two might help to follow your logic. Dangerously
    > assuming that both cameras used sensors having the same size, with a
    > 3:1 zoom ratio the 9mp camera at 18mm fl would have captured what
    > the 3mp camera did at 55mm in a cropped section containing only
    > 1/9th of its 9 megapixels. Oops, I guess that you did get it right,
    > since if the sensor was 27mp, 1/9th of its (really tiny, cruddy)
    > pixels would match the other sensor's 3mp. So as far as what you
    > heard in the store is concerned, the sales droid's logic is null and
    > void. :)
    >
    >
    > > For me at least, the megapixel race is over. A 10mp APS sized sensor
    > > is going to need good glass to get the resolution needed to make good
    > > pictures. My next step would be full frame, but I need to get 3 years
    > > out of my XTi investmant.

    >
    > Until then you can do as some others have. Whenever they want
    > really high resolution images, subject permitting, they create very
    > high resolution stitched panoramics. This may be less convenient
    > than using a full frame camera, but it has a couple of advantages,
    > including much higher potential resolution as well as a much wider
    > angle, more than offsetting the FF's inherent wide angle advantage
    > from a particular lens if only a single frame is used.

    This is the route I took. I was looking at the 10-22mm Canon lens and
    realized that I would spend less for a really good panoramic head and
    the photos would be much sharper as well.

    What is amazing is you get a whole new view of what hi-resolution is,
    when I stitch 50MP is a very small photo. To get a 50MP photo I only
    need to take 10 photos, two rows of 5. I use a fair bit of overlap
    which is why I reduce 10 8MP photos down to 50MP. With the panoramic
    head it only take 20 seconds to take the 10 photos and the stitching
    takes about 7 minutes. Images in the 100 to 150MP range are pretty
    easy and I have gone close to 400MP, but then the computer begins to
    choke on the size of the image.

    Scott
    Scott W, Nov 24, 2006
    #8
  9. JohnR66

    timeOday Guest

    Scott W wrote:

    >
    > What is amazing is you get a whole new view of what hi-resolution is,
    > when I stitch 50MP is a very small photo. To get a 50MP photo I only
    > need to take 10 photos, two rows of 5. I use a fair bit of overlap
    > which is why I reduce 10 8MP photos down to 50MP. With the panoramic
    > head it only take 20 seconds to take the 10 photos and the stitching
    > takes about 7 minutes. Images in the 100 to 150MP range are pretty
    > easy and I have gone close to 400MP, but then the computer begins to
    > choke on the size of the image.
    >
    > Scott
    >


    What does anybody do with those high-res stitched images Billboards?
    But even that wouldn't make sense because nobody views billboards up
    close. It's kinda fun to zoom in on your PC and scroll around and go
    "whoah, lotsa pixels"... but then what?
    timeOday, Nov 24, 2006
    #9
  10. JohnR66

    frederick Guest

    timeOday wrote:
    > Scott W wrote:
    >
    >>
    >> What is amazing is you get a whole new view of what hi-resolution is,
    >> when I stitch 50MP is a very small photo. To get a 50MP photo I only
    >> need to take 10 photos, two rows of 5. I use a fair bit of overlap
    >> which is why I reduce 10 8MP photos down to 50MP. With the panoramic
    >> head it only take 20 seconds to take the 10 photos and the stitching
    >> takes about 7 minutes. Images in the 100 to 150MP range are pretty
    >> easy and I have gone close to 400MP, but then the computer begins to
    >> choke on the size of the image.
    >>
    >> Scott
    >>

    >
    > What does anybody do with those high-res stitched images Billboards?
    > But even that wouldn't make sense because nobody views billboards up
    > close. It's kinda fun to zoom in on your PC and scroll around and go
    > "whoah, lotsa pixels"... but then what?



    I can only print at 13 x 19" at home at the moment. A "true" 300ppi
    landscape print at that dimension is awesome - but that's "only" a 22mp
    image. So, I obviously need a bigger printer. Perhaps my wife will get
    me an HP Z3100 44" 12 colour printer for Xmas. Then I'll need 250mp
    images @ 300dpi. Should be able to get that with a Hassy / Phase One
    P45 out of about 8 stitched images. I'll ask for that (and a new PC)
    for my birthday. Beyond that it's probably starting to get a bit
    pointless, so I'd be happy for a couple of years.
    frederick, Nov 24, 2006
    #10
  11. "timeOday" <> wrote:
    > Scott W wrote:
    >>
    >> What is amazing is you get a whole new view of what hi-resolution is,
    >> when I stitch 50MP is a very small photo. To get a 50MP photo I only
    >> need to take 10 photos, two rows of 5. I use a fair bit of overlap
    >> which is why I reduce 10 8MP photos down to 50MP. With the panoramic
    >> head it only take 20 seconds to take the 10 photos and the stitching
    >> takes about 7 minutes. Images in the 100 to 150MP range are pretty
    >> easy and I have gone close to 400MP, but then the computer begins to
    >> choke on the size of the image.

    >
    > What does anybody do with those high-res stitched images Billboards? But
    > even that wouldn't make sense because nobody views billboards up close.


    They do in Tokyo. All the train and subway stations here have billboards
    that are right on the platform, and people walk right by them. Many are shot
    with LF and look great. The few that aren't look pretty bad. There's a 7
    foot by 14 foot backlit photograph in Shinjuku station (the busiest station
    in Tokyo) that's pretty neat, although grainy. Again, right where people can
    walk up to it.

    For the rest of the world, people in galleries walk up to prints. That's why
    LF has remained the tool of choice for landscape types for so long.

    > It's kinda fun to zoom in on your PC and scroll around and go "whoah,
    > lotsa pixels"... but then what?


    Print large. 16x24 at 300 ppi requires 346 MP. Quality prints at larger
    sizes that stand up to close inspection can be devastatingly beautiful.

    David J. Littleboy
    Tokyo, Japan
    David J. Littleboy, Nov 24, 2006
    #11
  12. JohnR66

    Scott W Guest

    David J. Littleboy wrote:
    > "timeOday" <> wrote:
    > > Scott W wrote:
    > >>
    > >> What is amazing is you get a whole new view of what hi-resolution is,
    > >> when I stitch 50MP is a very small photo. To get a 50MP photo I only
    > >> need to take 10 photos, two rows of 5. I use a fair bit of overlap
    > >> which is why I reduce 10 8MP photos down to 50MP. With the panoramic
    > >> head it only take 20 seconds to take the 10 photos and the stitching
    > >> takes about 7 minutes. Images in the 100 to 150MP range are pretty
    > >> easy and I have gone close to 400MP, but then the computer begins to
    > >> choke on the size of the image.

    > >
    > > What does anybody do with those high-res stitched images Billboards? But
    > > even that wouldn't make sense because nobody views billboards up close.

    >
    > They do in Tokyo. All the train and subway stations here have billboards
    > that are right on the platform, and people walk right by them. Many are shot
    > with LF and look great. The few that aren't look pretty bad. There's a 7
    > foot by 14 foot backlit photograph in Shinjuku station (the busiest station
    > in Tokyo) that's pretty neat, although grainy. Again, right where people can
    > walk up to it.
    >
    > For the rest of the world, people in galleries walk up to prints. That's why
    > LF has remained the tool of choice for landscape types for so long.
    >
    > > It's kinda fun to zoom in on your PC and scroll around and go "whoah,
    > > lotsa pixels"... but then what?

    >
    > Print large. 16x24 at 300 ppi requires 346 MP. Quality prints at larger
    > sizes that stand up to close inspection can be devastatingly beautiful.
    >


    I come up with 35MP for a 16 x 24 print at 300 ppi.

    My new favorite size is 20 x 30, which takes 54MP

    I have had prints up to 30 x 60 made, 162MP.

    As the years have gone by larger prints have gotten both easy to get
    and cheaper. The photographs that you take today you might well want
    to print very large in 20 years.

    50 to 100 MP seems like a nice size image, larger enough to make a good
    large print but small enough that you can get a decent DOF.

    Scott
    Scott W, Nov 24, 2006
    #12
  13. "Scott W" <> wrote:
    > David J. Littleboy wrote:
    >>
    >> Print large. 16x24 at 300 ppi requires 346 MP. Quality prints at larger
    >> sizes that stand up to close inspection can be devastatingly beautiful.

    >
    > I come up with 35MP for a 16 x 24 print at 300 ppi.


    Sheesh, stop quibbling. It's only one measly order of magnitude I'm off<g>.

    > My new favorite size is 20 x 30, which takes 54MP


    This is Japan; I don't have a wall with that much space on it<g>. But I did
    see an exhibit of 35mm 20 x 30 prints here that I thought were completely
    unacceptable mush.

    > As the years have gone by larger prints have gotten both easy to get
    > and cheaper. The photographs that you take today you might well want
    > to print very large in 20 years.


    That's a good point. Still, I doubt there's a more-than-12.7MP camera in my
    future for a long time. The only high-MP stuff I might do is panoramas with
    the camera mounted vertically.

    > 50 to 100 MP seems like a nice size image, larger enough to make a good
    > large print but small enough that you can get a decent DOF.


    Your next project is to figure out how to stitch with the 45 or 90mm TSE
    lenses doing Scheimpflug games to get great apparent DOF.

    David J. Littleboy
    Tokyo, Japan
    David J. Littleboy, Nov 24, 2006
    #13
  14. David J. Littleboy wrote:

    > Your next project is to figure out how to stitch with the 45 or 90mm TSE
    > lenses doing Scheimpflug games to get great apparent DOF.


    You don't need tilts or shifts with or small apertures to
    get high depth of field. See:

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

    This is a mosaic of 2 4x5 (film) scanned images,
    23,440 x 11,840 pixels (this one did use a small tilt on
    the view camera):
    http://www.clarkvision.com/gallerie...orado.fall.c10.01.2003.L4.9536.a b.c.700.html

    So, one can stitch film or digital, of any size to get pretty much any
    size one wants, and it gets easier with faster computers.

    But mosaicking doesn't work for everything, like full frame fireworks
    or other fast moving subjects.

    Roger
    Roger N. Clark (change username to rnclark), Nov 24, 2006
    #14
  15. JohnR66

    Scott W Guest

    Roger N. Clark (change username to rnclark) wrote:
    >
    > You don't need tilts or shifts with or small apertures to
    > get high depth of field. See:
    >
    > Large Digital Mosaics as a Substitute for Large Format Film
    > http://www.clarkvision.com/photoinfo/large_mosaics


    I have just started getting back into refocusing between shots, some
    scenes this works very well for some it is much harder to get to look
    right.

    I am also trying to decide just how much resolution I want in my
    photos. For anything that I might print big the 50 MP range seems
    about right since that yields a 20 x 30 print at 300 ppi. But a small
    change from 300ppi to 400ppi and the size jumps from 54MP to 96MP for a
    20 x 30 print.

    So for large prints I am thinking 54MP is about the sweet spot for me,
    I will continue to make some larger photos as well. At 54MP I can
    mostly avoid the need for doing refocusing and just pick one focal
    point where makes things go much faster and takes far fewer images.

    Then there are photos that I take to document how and area looks at the
    present time, for this I don't think you can have too much
    resolution.

    Scott
    Scott W, Nov 24, 2006
    #15
  16. JohnR66

    DHB Guest

    On Thu, 23 Nov 2006 23:13:08 -0700, timeOday
    <> wrote:

    >Scott W wrote:
    >
    >>
    >> What is amazing is you get a whole new view of what hi-resolution is,
    >> when I stitch 50MP is a very small photo. To get a 50MP photo I only
    >> need to take 10 photos, two rows of 5. I use a fair bit of overlap
    >> which is why I reduce 10 8MP photos down to 50MP. With the panoramic
    >> head it only take 20 seconds to take the 10 photos and the stitching
    >> takes about 7 minutes. Images in the 100 to 150MP range are pretty
    >> easy and I have gone close to 400MP, but then the computer begins to
    >> choke on the size of the image.
    >>
    >> Scott
    >>

    >
    >What does anybody do with those high-res stitched images Billboards?
    >But even that wouldn't make sense because nobody views billboards up
    >close. It's kinda fun to zoom in on your PC and scroll around and go
    >"whoah, lotsa pixels"... but then what?


    Then what? Well check out the increased use of panoramic
    pictures in high end real estate where a 360 degree panoramas can be
    done of each room in an expensive home that is up for sale. People
    with lot's of money don't always have time to visit each place of
    interest especially if it's outside their country, so a virtual tour
    via the Internet becomes a viable option to narrow the choices
    considerably.

    The same in also true of some of the most expensive hotels, in
    most cases you can pan around & even zoom in to areas of interest.
    What is of interest to 1 person may be very different from what is of
    interest to another. Thus being able to Pan/Tilt/Zoom including the
    view from the balcony, can be of considerable usefulness.

    Just my 2 cents worth.

    Respectfully, DHB


    "To announce that there must be no criticism of the President,
    or that we are to stand by the President, right or wrong,
    is not only unpatriotic and servile, but is morally treasonable
    to the American public."--Theodore Roosevelt, May 7, 1918
    DHB, Nov 24, 2006
    #16
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