Michael Briggs , Jan 05, 2004; 01:29 a.m.
Some people who want "funky" lenses are making their own, perhaps using a two element achromat purchased from a surplus dealer. However, I think you will find making a state-of-the-art lens a daunting do-it-yourself project. Suppose you design you own Tessar-type lens: you will have selected four glasses (you will use their refractive index and dispersion in the design calculations), four thicknesses and eight curvatures. These characteristics and the spacings will have precise intended values. The chance that you will find these four glass pieces available off-the-shelf (i.e., pre-made) are about nil. If you should manage to find the four elements, or you design a lens around available elements, then you will need to design and make a mounting barrel that centers and spaces them to high accuracy. This all can be done with 19th technology, so in principle an individual could make their own Tessar, grinding and polishing the elements and machining the mount. But the amount of work would be staggering compared to the price of a new one, and especially to the price of a used one. Your hobby would be lens making rather than photography!
With LF lenses being so available on the used market, I can see making a lens or having a lens custom made only for very special cases: wanting a simple, funky lens or to create an otherwise unobtainable lens, e.g., a wide-angle for an extreme ultra-large format.
The book "Lens Design Fundamentals" by Rudolf Kingslake has some examples in which lens are designed with explanations of the design steps and considerations. Perhaps some version of one of the simplest designs could be made with off-the-shelf components, e.g., something like the narrow-field "portrait" lens that Kingslake shows on page 227.