[alexbock]

> Are there algorithms to select the lens elements for me given the properties I want?

I plan to add optimization features in the future to automatically tune design parameters to suit specified target criteria, as well as some application-oriented design generators for things like telescopes, binoculars, and camera lenses.

In the current version, the only features that automatically determine system specifications to achieve a specific result are autofocus for the distance from the last surface to the image, and a generator that produces a planoconvex singlet lens given a specified focal length and glass material.

> How does one buy lens elements? Are they custom manufactured or out of a catalog?

If I need some basic singlets or achromatic doublets for a visible-light use case that does not place strict requirements on the specific type of glass or the precise specifications of their AR coatings (if any), then I will typically order from Surplus Shed. They are significantly cheaper than other domestically shipped (US) sources for individual lens elements, but it is often necessary to design around the diameters and focal lengths that they have in stock rather than designing a finished system first and ordering exactly what it needs.

For specialized components like infrared and ultraviolet optics or for parts with formally documented specifications and product line consistency, I order from Thorlabs. They are more expensive.

Both Surplus Shed and Thorlabs will sell directly to individuals from their online stores. I have no affiliation with either company.