EXIF Reader -> Focus Distance

TelecorderTelecorder Registered Users Posts: 73 Big grins
edited November 26, 2010 in Cameras
Came across a free EXIF reader that some might be interested in--
http://www.softpedia.com/progDownload/KUSO-Exif-Viewer-Download-52677.html
For Nikon D-lenses, it will give you the details for -->
Field of View in Degrees
Circle of Confusion
Depth of Field in meters
Focus Distance in meters
Hyperfocal Distance
as well as a lot more detail image/lens info...

Now one can have a bit better idea of just how far that subject was at the time of the image...

Its unclear, though, as to just how accurate the Focus Distance reading is to actual subject distance. I've checked the Focus Distance info on a number of images where I know the distance and it seems to be fairly accurate.

At the same time, though, I have other images where it doesn't make sense showing Focus Distance to a plane-in-flight's image as being at 74.99-meters and there's no way it was that close to me... Maybe I'm not understanding of how the Focal Distance vis a vis Hyperfocal distance is coming into play...
Perhaps others might enlighten me...
Telecorder (Dave)
Apple Valley, CA
D50-BIGMA-70-300VRII-35f2D-18-70DX-FZ30
My SmugMug Image Galleries
My Nikonian Image Galleries

Comments

  • ziggy53ziggy53 Super Moderators Posts: 23,764 moderator
    edited March 5, 2008
    Good find! Thanks for sharing the link. thumb.gif
    ziggy53
    Moderator of the Cameras and Accessories forums
  • TelecorderTelecorder Registered Users Posts: 73 Big grins
    edited March 5, 2008
    A poster in DPR indicated that--
    "Different lenses have a different maximum distance beyond which the lens exif reports a fixed distance the longer the lens the greater the maximum distance reported.
    For the AF-S 300mm f2.8G ED VR it is ~49metres, for my Sigma 800mm f5.6 it is 125m , within their working ranges the distances reported with these two lenses are very accurate. I've checked the Sigma against Digital OS GB maps and it is certainly within 20cm in 100m.
    I test all my lenses using a test chart calibrated for 40 focal lengths and at this distance the two lenses above report the distance to an accuracy of a couple of cm."

    This may well be as my 70-300VR maximum reported Focus Distance seems to be to 21.3-meters while my Bigma is 74.99-meters.

    Mothman13 did a chart for a Nikon D80 with a 1.5X crop Factor for different FOV image sizes (18mm - 600mm)... Look at the vertical height of the field of view at each subject distance.

    http://www.pbase.com/mothman13/image/74511515 (5 - 30 feet)
    http://www.pbase.com/mothman13/image/74511517 (35 - 60 feet)

    Using my D50/Bigma, I've derived the additional following relationship...
    Subject Distance -- ~Vertical FOV (assuming 2,000 vertical pixels)
    50-ft -- 20"
    100-ft -- 40"
    200-ft -- 72"
    300-ft -- 110"
    400-ft -- 140"
    500-ft -- 175"
    600-ft -- 210"

    At least with the KUSO reader, it would appear the Focus Distance reported within the lens' setup is fairly accurate. I need to do some more controlled tests but this image was taped at 50-feet

    DSC_5818Medium1.jpg

    And the KUSO EXIF indicates...
    Standard Information
    Make: NIKON CORPORATION
    Model: NIKON D50
    ImageSize: 3008x2000
    CreateDate: 2007:01:02 14:48:25
    ExposureTime: 1/1250"
    Aperture: F6.3
    MaxAperture: F6.3
    DepthOfFocus: 0.25 m (15.73 - 15.97)
    CircleOfConfusion: 0.020 mm
    HyperfocalDistance: 1981.07 m
    FocalLength: 500.0 mm
    FocalLength35efl: 500.0 mm (35 mm equivalent: 750.0 mm)
    LensSpec: 50-500mm f/4-6.3 D
    FocusDistance: 15.85 m --> 51.9-feet....
    FocusMode: Manual
    MaxFocalLength: 508.0 mm
    MinFocalLength: 50.4 mm


    Perhaps not as much accuracy as I'd hope +3.8%
    Telecorder (Dave)
    Apple Valley, CA
    D50-BIGMA-70-300VRII-35f2D-18-70DX-FZ30
    My SmugMug Image Galleries
    My Nikonian Image Galleries
  • kithylinkithylin Registered Users Posts: 229 Major grins
    edited November 26, 2010
    I know it's bad forum etiquette to dig up old threads, but this is a great program, and thought i would add it also reads RAW NEF files from Nikon cameras.
    Sony Alpha SLT-A35 16.5 MP DSLR
    Minolta AF Zoom 70-210 F/4.5-5.6
    Minolta AF Zoom 35-70 F/3.5-4.5
    Places I post my work DeviantArt & FLICKR
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