First things first: If bought by owners of Sony DSC-F7x7 cameras, this lens is being marketed in a very dangerous configuration. You will find it listed for sale online (or even still sold by Adorama) with a Series-7 to 58mm adapter ring. DO NOT BUY IT THIS WAY -- YOU CAN END UP RUINING BOTH YOUR F7x7 LENS AND THIS LENS! (I've alerted Adorama to this problem, whether their salespeople will catch the error or not when you order it is anyone's guess.) When it first arrived I noticed something suspicious, the back lens of the Pro Optic is highly convex. Before even attaching it to the camera with the included S7-58mm ring I did some measurements. Because the S7-58mm adapter screws down so deep into the Sony lens, and the Sony lens itself is highly convex, the glass from each will smash into the other. If completely tightened down the lenses would grind through each other for a 2mm-4mm distance. I doubly-confirmed this by putting a small fold of tissue paper between the lenses and then watched through the fish-eye lens as the 2-ply fold of tissue was being smashed down. I stopped long before any pressure could harm either lens. To circumvent this problem I first made a thick, hard-plastic, spacer-ring, but that only allowed the lens to be held on by one turn of the threads. Instead I ordered an alternate Series-7 to 62mm adapter ring, and a 58mm to 62mm step-up ring. This was enough to give it plenty of safety room. You can see the problem in the photos below. This was also a convenient size so it could also be used with some 35mm lenses that I have for a 35mm camera -- as well as enough outside flange to get a good grip to unscrew it from the Sony lens (the original S7-58 ring would thread so deep into the Sony lens that it was even difficult to remove, nothing left to grab onto). You may want to order a different size so it is more adaptable to other lenses that you own too.