Greeting & Salutations all CiC members. I'll bet everyone has tried this before. I was playing around with this technique the other day with an old sound card I had lying around. I lay the PC board on the floor and just let the weight of the lens slide down, using a 1/2 second exposure.
The trick is to get the effect to commence at just the right moment so that the focal point at the centre remains sharp. This the best I could do...any ideas on how to improve overall sharpness?