# 2 lens microscope with an iphone camera. Where should the imaging plane be?

I am trying to design a 2 lens microscope that can be attached to an iphone camera in Zemax. To optimize the point spread function I need to define an imaging plane at which it should be optimized. Should the imaging plane of the 2 lens system be positioned at the surface of the camera or behind it? Do I need to take into account the internal optical system of the phone to get meaningful results?

Any help would be highly appreciated!

• What magnification do you want? Microscope objective lens is defined by magnification / NA. If you know, what you want you only have to google BFL/FFL of your specific iphone model. Without this input you will no be able to solve your problem. – Stefan Bischof Nov 23 '17 at 0:41
• Typically it would be focussed at infinity if you are using the existing iPhone camera as the 'eyepiece' – Martin Beckett Nov 23 '17 at 0:49

So, at the very least, you need to work out the stop diameter from the camera's $f$ number and also the effective focal length.