Hello to everyone,
Inside the focusing mechanism of the HN150 there is the coma corrector screwed in. For maintenance and cleaning, it can be removed easily. Now my question - does anyone know how deep it needs to be inside? The correction is done on the side of the camera, but is it important to screw it in to a certain depth inside the focus mechanism?
I hope you can understand my question - sorry, English is not my primary language!
Thanks and CS,
Georg
andrea tasselli · Oct 23, 2025, 08:35 AM
It is NOT a coma corrector as hyperbolic newtons are correct for coma. It corrects for spherical and astigmatic field curvature. And the best way to go about this sort of stuff is always to ask the manufacturer first, you know; take the thing from the horse's mouth… In this specific instance the answer is that it is irrelevant, since what matters is the distance from front corrector surface to the camera which doesn't change.
Thanks a lot Andrea, I hoped you would read and answer since your replies and answers are very constructive and helpful !
I asked already the manufacturer but I was thinking, maybe someone knows the answer from a previous inquiry…