Hi, I'm SrPantuflas and welcome to this tutorial, done for this boring sunday. the goal is be able to fix the past infinity focus on the Fujian CCTV 35mm f1.7, using a very cheap and dubious quality method. haha. what we need: a lens (duh) an adaptor scissors, x-acto or very sharp teeth a piece of EVA foam beer (optional-not pictured) i used 2mm foam here, maybe 3mm would be better for this. just cut a donut shaped foam using the scissors, the x-acto or your teeth (hard mode) keep the inner circle a bit wider than the adaptor circle for the lens. i did not take a photo of the cutted foam because i'm so bad at cutting that you'll laugh at me. but it worked. drink the beer. now put the lens into the adaptor, i use the adaptor always with this lens so having a piece of foam there is not a problem notice how the lens protrudes a little bit more now then put the lens on the camera, test the focus, turn a bit more or less the lens to fine tune it, and voilá! total cost: 0,2 dollars for the foam sheet + the price of the beer. thanks for reading!