Optical Misalignment: Estimating Error and Its Impact on Focal Length

[TW Cantor]

Hi all

I was just wondering if anyone could help me with estimating error caused by misalignment of an optical arrangement. I am interested in how the focal length of this arrangement will be affected by say a misalignment of just one of the lenses. I'll assume that every component is aligned in the horizontal and vertical and that it is just a slight angular misalignment.

Say I have a laser followed by two lenses. Is there an equation to find the focal length of the system when the first lens is out of alignment by x degrees? Or will it actually have little effect on the focal length and just move the position of the focal point?

Any help would be appreciated

 

[Drakkith]

I don't think it will have any effect on the focal length, but it would introduce aberrations in the converging light cone and the focal plane may be tilted slightly.

 

[Andy Resnick]

Tilting a lens typically results in astigmatism.

http://www.healio.com/~/media/books/ophthalmology/iol%20power/excerpt%20pdf%203.ashx

http://www.google.com/url?sa=t&rct=...IKsPqu1mQqm5_8wLzg&bvm=bv.61535280,bs.1,d.aWM