D70 resolution: 3008x2000 - what's the 8 all about

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

  1. paul

    paul Guest

    The D70 resolution is 3008x2000 pixels.

    What is the extra 8 pixels all about?

    Not that it matters I suppose, just curious.
     
    paul, Jan 1, 2005
    #1
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  2. paul

    John Bean Guest

    3000 isn't divisible by 16, 3008 is.

    The answer to your next question is to allow lossless rotation of JPEGs :)

    --
    John Bean

    The most likely way for the world to be destroyed, most experts agree, is by
    accident. That's where we come in; we're computer professionals. We cause
    accidents (Nathaniel Borenstein)
     
    John Bean, Jan 1, 2005
    #2
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  3. paul

    leo Guest


    Why would you care? The Sony sensor used in the D70 doesn't have the 3:2
    ratio anyway. A 35mm film is 36mmx24mm. Sony's chip is 23.7mmx15.6mm and
    that makes the crop factor comes out to somewhere between 1.519x and
    1.538x. Just for comparison, Canon's sensor is 22.5mmx15mm which is
    exactly 1.6x.
     
    leo, Jan 2, 2005
    #3
  4. And MY next question is "How does 3008x2000 equate to the advertised 6.1
    megapixels?" Seems to me it should be 6.016 megapixels.

    Merritt
     
    Merritt Mullen, Jan 2, 2005
    #4
  5. One presumes that marketing are allowed to round anything up!

    Actually 3008 x 2000 is:-

    6.016 million pixels

    5875 KP (if K = 1024)

    5.74MP (if M = 1024 x 1024)

    So if the computing definition of mega were used, the camera is only
    5.74MP!

    (Some people complained a while back that not all "128MB" CF cards had the
    same capacity, and indeed it seems that some manufacturers use the MB =
    1000000 bytes and other use MB = 1024 * 1024 bytes).

    Cheers,
    David
     
    David J Taylor, Jan 2, 2005
    #5
  6. paul

    John Bean Guest

    You'll have to ask the whoever writes the advertising copy ;-)

    FWIW my Pentax DS (with the same sensor) delivers 3008x2008 raw files, but
    crops JPEGs to 3008x2000.

    --
    John Bean

    In all large corporations, there is a pervasive fear that someone, somewhere
    is having fun with a computer on company time. Networks help alleviate that
    fear (John C. Dvorak)
     
    John Bean, Jan 2, 2005
    #6
  7. paul

    Lourens Smak Guest


    Why would you care? The Sony sensor used in the D70 doesn't have the 3:2
    ratio anyway. A 35mm film is 36mmx24mm. Sony's chip is 23.7mmx15.6mm and
    that makes the crop factor comes out to somewhere between 1.519x and
    1.538x. Just for comparison, Canon's sensor is 22.5mmx15mm which is
    exactly 1.6x.[/QUOTE]

    why post an answer if you are totally clueless?

    Lourens
     
    Lourens Smak, Jan 2, 2005
    #7
  8. paul

    Alan Browne Guest

    Lossless rotation can be maintained by merely keeping the number of pixels the
    same, eg: 3000 x 1500 -> 1500 x 3000 (or whatever dimesnions you please).

    The 3008/16 is, as you imply, simply adopting the digital 'rounding' boundary
    that takes place with most digital devices.

    Cheers,
    Alan
     
    Alan Browne, Jan 2, 2005
    #8
  9. paul

    JPS Guest

    In message <>,
    There is a border of RAW image data around the edges that most cameras
    making JPEGs or RAW converters will toss away in the process. There are
    also areas of pixels that are not exposed to light at all.
    --
     
    JPS, Jan 2, 2005
    #9
  10. Alan Browne wrote:
    []
    Alan, I think you will find that lossless rotation requires that the image
    dimensions be a multiple of 16 (and not 8 as I incorrectly stated
    earlier).

    Cheers,
    David
     
    David J Taylor, Jan 2, 2005
    #10
  11. paul

    Alan Browne Guest

    I fail to understand why. A matrix of 7 x 11 has the same quantity of
    information as a matrix of 11 x 7. Assuming the rotation is correctly done (and
    after conversion of individual R,G,B sensor to RGB pixels) then it makes no
    matter at all.

    Cheers,
    Alan
     
    Alan Browne, Jan 2, 2005
    #11
  12. If the image is JPEG, then the indivdual blocks are 16 x 16. The size
    quantisation restriction only applies to JPEG images, but of course almost
    all cameras do allow JPEG images as output.

    If the image is not JPEG then it can, of course, be losslessly rotated at
    any size - as you say.

    Cheers,
    David
     
    David J Taylor, Jan 2, 2005
    #12
  13. paul

    Darrell Guest

    <rant>
    It seems mega has two different meanings, in storage it's 1,024x1,024. But
    in pixels it's the actual number. Same math my ISP uses for throughput speed
    ;) I also would prefer CF cards speeds be in mbps not 40X, 80X etc..
    </rant>
     
    Darrell, Jan 2, 2005
    #13
  14. paul

    Darrell Guest

    Are the photosites in the sensor grid perfect squares? a 7x11 grid of
    rectangles is not the same 7x11 as it would be at 11x7
     
    Darrell, Jan 2, 2005
    #14
  15. paul

    leo Guest


    Why not. As the ratio indicates, there is more width info than height in
    the sensor (0.3mm wider). It might even translate into 8 pixels...
     
    leo, Jan 2, 2005
    #15
  16. Darrell wrote:
    []
    You will be delighted to hear that both my SanDisk Ultra II CF and my
    wife's Kingmax Platinum SD cards do indeed carry a read and write MB/s
    rating....

    David
     
    David J Taylor, Jan 2, 2005
    #16
  17. paul

    John Bean Guest

    Thank you David, exactly correct :)
     
    John Bean, Jan 2, 2005
    #17
  18. The correct answer is already given. 3008 is possible to divide by 16.
    Thats it - nothing more to see here - please move along.


    /Roland
     
    Roland Karlsson, Jan 2, 2005
    #18
  19. paul

    Alan Browne Guest

    Now I'm really confused. Nothing prevents me from editing a JPG image to 1
    pixel in either dimension. I can easilly come out with a 111 x 213 pixel image
    in JPG. From there, I can rotate it to 213 x 111 and it contains the same info.
    I can then save it at full quality. I've lost nothing.

    Getting back on track, the reason we end up with 3008x2000, IMO, (D70, Maxxum
    7d, et al) is that the hardware and software can be designed in even boundaries
    of 16 (or 8) and that is convenient to the engineers in terms of performace/$.
     
    Alan Browne, Jan 2, 2005
    #19
  20. paul

    Alan Browne Guest

    On the sensor in the D70 and Maxxum 7d I'm not sure they are really perfect
    squares. The data on dpreview suggests perhaps not. (pixel dimensions v.
    sensor dimensions. It's not clear what is 'cropped' by the camera when reading
    the device).

    In the Canon 20D they do appear to be square..
     
    Alan Browne, Jan 2, 2005
    #20
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