CCD size and focal length

Discussion in 'Digital Photography' started by itsperu, Jul 6, 2004.

  1. itsperu

    itsperu Guest

    I already saw a thread on this topic...but anyway...
    Is there anyway to calculate the angle of view for a digital camera,
    given its focal length and CCD size? (Canon Powershot A40 datasheet
    tells me its 5.4mm-16.4mm focal length & CCD size is 1/2.7")
    Can I assume the CCD size to be the diagonal and calculate FOV? or how
    do i calculate effective CCD area?
    Also, can anyone guide me a (simpler :D) way to use WIA or Canon SDK
    to acquire just the FOV from the digicam?
    Perumaal
     
    itsperu, Jul 6, 2004
    #1
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  2. itsperu

    jpc Guest

    On 5 Jul 2004 22:50:19 -0700, (itsperu) wrote:

    >I already saw a thread on this topic...but anyway...
    >Is there anyway to calculate the angle of view for a digital camera,
    >given its focal length and CCD size? (Canon Powershot A40 datasheet
    >tells me its 5.4mm-16.4mm focal length & CCD size is 1/2.7")
    >Can I assume the CCD size to be the diagonal and calculate FOV? or how
    >do i calculate effective CCD area?
    >Also, can anyone guide me a (simpler :D) way to use WIA or Canon SDK
    >to acquire just the FOV from the digicam?
    >Perumaal



    It's very simple triginometry. The light ray that goes thru the
    center of the lens and hits the center of the ccd is the base of the
    triangle, the lightr ray that goes thru the center of the lens and
    hits the edge of the ccd is the second side and the top half of the
    ccd is the third side. Given two of the sides you can calculate the
    respective angles or lengths of the the third side.

    jpc
     
    jpc, Jul 6, 2004
    #2
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  3. "itsperu" <> wrote in message
    news:...
    > I already saw a thread on this topic...but anyway...
    > Is there anyway to calculate the angle of view for a digital camera,
    > given its focal length and CCD size? (Canon Powershot A40 datasheet
    > tells me its 5.4mm-16.4mm focal length & CCD size is 1/2.7")
    > Can I assume the CCD size to be the diagonal and calculate FOV? or how
    > do i calculate effective CCD area?
    > Also, can anyone guide me a (simpler :D) way to use WIA or Canon SDK
    > to acquire just the FOV from the digicam?
    > Perumaal


    Perumaal,

    See here for information on sensor sizes:

    <http://www.dpreview.com/learn/?/Glossary/Camera_System/Sensor_Sizes_01.ht
    m>

    The normal formulae apply.

    The FOV will be in the EXIF header (somewhere) if you use JPEG. Can't
    help with WIA or SDK.

    Cheers,
    David
     
    David J Taylor, Jul 6, 2004
    #3
  4. (itsperu) writes:
    >I already saw a thread on this topic...but anyway...
    >Is there anyway to calculate the angle of view for a digital camera,
    >given its focal length and CCD size? (Canon Powershot A40 datasheet
    >tells me its 5.4mm-16.4mm focal length & CCD size is 1/2.7")
    >Can I assume the CCD size to be the diagonal and calculate FOV? or how
    >do i calculate effective CCD area?
    >Also, can anyone guide me a (simpler :D) way to use WIA or Canon SDK
    >to acquire just the FOV from the digicam?


    The most accurate way to calculate FOV is get the actual pixel pitch of
    the sensor from the EXIF header (all Canon cameras I've looked at store
    this in every image). Multiply pixel pitch by the image width and
    height and you get the actual dimensions of the light-sensitive area of
    the sensor. Knowing the width and height of the sensor, and the lens
    focal length, you can easily calculate field of view as

    HFOV = 2 * atan(width/2/FL)
    VFOV = 2 * atan(height/2/FL)

    Using the "1/2.7" nominal size is less accurate, first because 2.7 is an
    approximate number, and because it refers to an "inch" that's about 16
    mm. So your sensor's diagonal is about 16/2.7 = 5.9 mm, but only
    approximately. The pixel pitch from the EXIF data should be far more
    accurate.

    Dave
     
    Dave Martindale, Jul 6, 2004
    #4
  5. itsperu

    itsperu Guest

    (Dave Martindale) wrote in message news:<ccevut$2q2$>...
    > (itsperu) writes:
    > >I already saw a thread on this topic...but anyway...
    > >Is there anyway to calculate the angle of view for a digital camera,
    > >given its focal length and CCD size? (Canon Powershot A40 datasheet
    > >tells me its 5.4mm-16.4mm focal length & CCD size is 1/2.7")
    > >Can I assume the CCD size to be the diagonal and calculate FOV? or how
    > >do i calculate effective CCD area?
    > >Also, can anyone guide me a (simpler :D) way to use WIA or Canon SDK
    > >to acquire just the FOV from the digicam?

    >
    > The most accurate way to calculate FOV is get the actual pixel pitch of
    > the sensor from the EXIF header (all Canon cameras I've looked at store
    > this in every image). Multiply pixel pitch by the image width and
    > height and you get the actual dimensions of the light-sensitive area of
    > the sensor. Knowing the width and height of the sensor, and the lens
    > focal length, you can easily calculate field of view as
    >
    > HFOV = 2 * atan(width/2/FL)
    > VFOV = 2 * atan(height/2/FL)
    >
    > Using the "1/2.7" nominal size is less accurate, first because 2.7 is an
    > approximate number, and because it refers to an "inch" that's about 16
    > mm. So your sensor's diagonal is about 16/2.7 = 5.9 mm, but only
    > approximately. The pixel pitch from the EXIF data should be far more
    > accurate.
    >
    > Dave


    Thanks a lot. I have to check out what is an EXIF header and how to
    read the chunk from JPG. Thanks on the info for EXIF!
    Perumaal.
     
    itsperu, Jul 8, 2004
    #5
  6. (itsperu) writes:

    >Thanks a lot. I have to check out what is an EXIF header and how to
    >read the chunk from JPG. Thanks on the info for EXIF!
    >Perumaal.


    Irfanview will display the Exif header data.

    Dave
     
    Dave Martindale, Jul 8, 2004
    #6
  7. itsperu

    itsperu Guest

    (Dave Martindale) wrote in message news:<ccip7a$695$>...
    > (itsperu) writes:
    >
    > >Thanks a lot. I have to check out what is an EXIF header and how to
    > >read the chunk from JPG. Thanks on the info for EXIF!
    > >Perumaal.

    >
    > Irfanview will display the Exif header data.
    >
    > Dave


    Thanks a ton. EXIF header by Tachabanaya (unofficial) was extremely
    helpful, and I was able to write a reader in VC .NET in under a day
    (considering that I knew just C++ but no VC .NET, the time length may
    be justified !)
    It works perfectly now.
    Thanks Dave!
    Perumaal.
     
    itsperu, Jul 10, 2004
    #7
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