Hello, all.

I am writing this to discuss about what is the best focus in Optic Studio.

The question occured to me when I optimized for only last distance from the image surface.

I set as variable for the thickness cell which placed former  surface of image surface to optimize.

and I set also criterion of optimisation as Spotsize and Wavefront to compare values of spot Diameter.

Definately, both were different as you predict, and the criterion of wavefront has more accuacy than the criterion of spot size if the design was really nice. (and it was)

However the thickness(distance) value after calculating of Optic Studio is different from original value caculated by another commercial software. 

Suddenly I thought that If I meet another situation which can not say the design is correct, it is truely tougher than this situation to say the the spot calculated by opticstudio is correct result.

how do you think or how do you do if you face similar situations.

Thank you for reading.