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Can anyone help me out with some basic fov calculations? (Answered)

Discussion in 'General Talk' started by Sniffles, Jul 26, 2019.

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  1. Sniffles

    Sniffles New
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    Hello. I have a health problem that effects my ability to concentrate and for the last 2 days I haven't been able to wrap my mind around some simple calculations. If anyone could help me out I would appreciate it a lot.

    What I need to do is calculate the distance I need to move a gantry across a linear rail so that each photo is overlapping by say 35% for photo stitching and calculate how many photos I would need to make across the linear rail.

    • I bought a 1500mm linear rail and with my camera on the gantry I have 1345.184 mm of horizontal travel.
    • My camera has a cropped sensor with a 1.53 crop factor.
    • My focal length is 50mm and the distance to my subject is 457.2mm.
    I calculated my camera has a:
    • Horizontal fov of about 214.88mm (horizontal aov 26.45°)
    • Vertical fov of 142.65mm (aov 17.73°)
    • A diagonal fov of about 257.92mm (aov 31.5°).
    Well I calculated 35% of the horizontal fov is 75.21mm and if I subtract that from the horizontal fov I get 139.67mm for the photo spacing. So if I take the total distance for making photos 1345.184/139.67mm I get 10 because I would have to round up. This is wrong of course because if I make a photo with the camera on the far side against the rail and then move it at 139.67mm intervals I end up with 11 photos, not 10.

    So the question is how do I calculate the distance I need to move the gantry across the linear rail so each photo is overlapping by 35% and how can I calculate how many photos I need to make across the rail?

    Can someone help me with this? :(
     
  2. Rick 2.0

    Rick 2.0 OpenBuilds Team
    Staff Member Moderator Builder Resident Builder

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    It takes 11 marks to define 10 intervals. You start with a shot and end with a shot that means the number of shots will always equal the number of intervals +1.
     
  3. Sniffles

    Sniffles New
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    Ugh yes, thank you very much. About 30 minutes ago I finally realized I was calculating the number of dividers NOT the spaces in between so to speak. So my calculations seem to be correct. I just completely got lost on that without realizing what you just said. Thank you Rick haha.
     

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