I did a lens calibration for my underwater camera/lens and I'm finding the value of the lens focal length to be narrower than advertised, a Nikonos 15mm, is coming in around 20mm. I'm using a Sony Full Frame A7 camera.
I understand the air-water interface for the dome port optic will make objects appear to be 25% closer, but maintain the angle of view.
What is the best way to adjust the OpenCV camera calibration math so that it gives me the right values when taking underwater images? All the math is based on distances and if objects appear 25% closer, then I would just need to throw in a scaling factor for distance. Just need to know where in the code to do that. Thanks.
Thanks.