Homemade Camera Podcast

E61 Paper Towel Tubes and BFL

Informações:

Sinopsis

This week we talk about making your own lenses, why Back Focal Length is meaningless to Ethan, and how to play around with loose achromat lens elements to make your own, homemade lens. The formula: Formula: F = (f1 x f2) / (f1 + f2 - d) BFL = (f2 x (d - f1)) / (d - (f1 + f2)) f1 is the front lens, f2 is the back lens, d is the distance between the lenses. F is the focal length, BFL is the distance between the back lens and the recording media (film, sensor) A link to a spreadsheet with the formula in it: https://docs.google.com/spreadsheets/d/1yQ3dsD0Rs-HflRcnPYHSmK0soLXtykGAPl8pdZcrBpM/edit?usp=sharing Special thanks to Erik Mathy (https://www.instagram.com/erikhmathy/ @erikmathy). We first heard about this formula on an episode of the Large Format Photography Podcast (https://largeformatphotographypodcast.podbean.com/) We also talk about a modified Adolescent Crown Graphic Nick's working on. Ethan mostly tells Graham his formula is wrong. Graham mostly tells Ethan he names his products after