I am now doing a more serious calibration for different lenses.
Here is an answer from another thread:
“[Oz]
The assumption when using the camera is that the distance from the camera to the top of your material will be constant, because the focus point of the beam is also constant. If you use a movable Z bed with a focus block or auto-focus, this will always be true. If you have an adjustable lens tube for focus, or change to a different focal length lens. it will not be true, and that will affect the camera calibration.”
Before I begin to mess up with that stuff, my biggest question:
I have a adjustable lens tube and a movable Z-axis.
If I understand it right, the camera is ALWAYS calibrated to the top surface of the material?
The camera view will be therefore correct if the Z-height of the top surface will stay constant, although I change the focus of the lens slipping the lens tube up or down?
The important part is that the relative position of the camera and top of the material is the same when you capture as it was when you ran the alignment.
If you have a focus tube that allows you to adjust your focus height without moving the Z that would change the distance from the material surface to the camera, and would affect the calibration.
If you have a focus tube to allow you to change lenses, and the actual distance from the camera to the focus plane of the laser ends up being the same, then it would be ok. For example, if I have a 25mm focus lens in a tube that is 50mm long, and I change it to a 50mm focus length lens in a 25mm long tube, then the distance from the camera to the material surface doesn’t change, so that’s ok.
If you used the shorter tube without changing the lens, that would make the focus distance closer to to the camera, and would break calibration.
the width/height option changes the width/height of the background picture?
for instance you have a 500 x 700 mm bed, and you insert +10 mm in both the picture will be then 510 x 710 mm?
