Strange Radial Distortion from SONY FE 24mm F1.4 GM lens

[MGap90]

Hi,

I recently started using the Sony FE 24mm F1.4 GM lens on my Sony a7R III and I'm getting strange results from my camera calibration (see attached images).

According to the radial distortion plot the lens distortion (pix) decreases past the 4000 pix radius of the lens.  That doesn't make sense to me and I have not seen that with other cameras or with other lenses on the Sony a7R III.

The images I collected were from 400 feet above ground level, 66% overlap and sidelap, shutter speed 1/2500, aperture F8, ISO 1600, fixed focus, internal sensor stabilization turned off.

Has anyone seen this behavior with this particular lens or have an explanation as to what is happening?

Thanks!

[dcobra]

I see similar results, although to a lesser degree, with my A7R III and 18mm Batis.  This is with stabilization and all in camera lens corrections off.

[WSurvey]

Has anyone seen this behavior with this particular lens or have an explanation as to what is happening?

Thanks!

How many radial distortion parameters are you using? if you are only solving for a couple of parameters then this might just be the best fit. What does your residual plot look like?

[MGap90]

Hi WSurvey,

I optimized the camera alignment checking all camera calibration parameters; Fit f, Fit cx cy, Fit k1, Fit k2, Fit k3, Fit k4, Fit b1, Fit b2, Fit p1, Fit p2, Fit p3, and Fit p4.

Attached is the residual plot.