L1 20C MF calibration

With the camera set to manual mode, aperture at f8, shutter at 1/8th with focus set to infinity. The aircraft gimbal was set to lock on exposure.

With manual focus set to infinity, the calibration characteristics are similar to the AF example but with smaller SD results. The K1 value shows the pin cushion distortion as detected by the AF example.

MF at infinity


ParametervalueSDUnit
f10.26mm
Exif mm
fx4376.111.34583
f in px
fy4274.171.28713
cx2726.420.818145
principal point px
cy0.507150.50715
skew0.9370240.0797351
k1-0.02240850.00123528
Radial distortion
k20.02962990.0103362
k30.02862310.0333362
p1-0.0002607713.08319e-005Tangential distortion
p20.0009193164.71262e-005

Comparison between the 2 calibrations shows new values for focal distance, a refined principal point and a slightly bigger K1 with similar tangental distortion values.

AFMF at infinity
fx = 4479.94 +- 2.26513fx = 4376.11 +- 1.34583
fy = 4374.51 +- 2.15679fy = 4274.17 +- 1.28713
cx = 2727.48 +- 0.813274cx = 2726.42 +- 0.818145
cy = 1811.92 +- 0.719281cy = 1784.7 +- 0.50715
skew = -1.91657 +- 0.0843506skew = 0.937024 +- 0.0797351
k1 = -0.0196948 +- 0.00126486k1 = -0.0224085 +- 0.00123528
k2 = 0.00652119 +- 0.010933k2 = 0.0296299 +- 0.0103362
k3 = 0.0909295 +- 0.0368218k3 = 0.0286231 +- 0.0333362
p1 = 0.000237354 +- 2.27565e-005p1 = -0.000260771 +- 3.08319e-005
p2 = 0.00108494 +- 3.73953e-005p2 = 0.000919316 +- 4.71262e-005

About billboyheritagesurvey

Heritage worker
Gallery | This entry was posted in SUA photography, Survey Practice. Bookmark the permalink.

2 Responses to L1 20C MF calibration

  1. Robert says:

    Thanks for this latest calibration, Bill, with manual focus set to infinity. Very helpful once again.
    What is the distance between the camera and the checkerboard target? Was it the same for the autofocus calibration?

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