This lens has been amazingly REMOUNTED to EF, DECLICKED AND with a CUSTOM LENS CAP from Ron Sim of Simmod, in Indiana. The lens's FOCUS, and IRIS have been GEARED by the very Sean McCurry at Follow Focus Gears in Georgia... **Who, for the first time ever, learned how to ENGRAVE F-STOP MARKINGS. He did this, for the first time into every one of these lens's iris rings and matched them appropriately to their LIGHT MEASUREMENTS. Way to go above and beyond, Cap'n. The iris turns past F16, F22 or F32 on all of the lenses, in this set, except the 50mm f3.5, 55mm f1.2 and the 135mm f2.0. Be careful when turning not to turn it past that point, otherwise it won't be adjusting exposure, accordingly. Ron Sim informed me that those connecting the iris to a follow focus should be careful. This is because the iris turns past it's "most closed" point on most of these lenses. My advice is, if you do connect the iris to a follow focus, you will need to manually calibrate the follow focus to know that the end of the iris is where it is, and not where the lens turns to. That would tear at the iris ring. So the iris ring is for reference and the knowledgeably careful. Turning the whole iris turn on a follow focus is bad for the lens and it isn't good to have that part in the focus puller's calibration either. So please leave that part of the iris turn for all practical purposes. These lenses all have 77MM INNER DIAMTERS and 80MM OUTER DIAMTETERS. So you can easily attach and swap 77mm variable nd filters between these lenses and you can attach an attachable mattebox such as the Misfit Atom to all of these lenses. This is the widest of the wide-angles and though just a small step away from the super wide-angle lenses, it's a lot easier to use. Second, there's a strong rendition of perspective that can be controlled quite easily. It's also a focal length that is growing in popularity with non-professional as well as professional cinematographers. The fastest Canon lens in the 35mm focal length before the debut of the EF 35mm f1.4. With a new 10-element, 8-group construction, the FD 35mm f/2 is approximately 25 percent shorter and 29 percent lighter than the earlier FD design. Focal length: 35mm Aperture ratio: 1:2 Lens construction: 8 groups, 10 elements Coating: S.S.C (super spectra coating) Angle of view: Diagonal: 63° Vertical: 38° Horizontal: 54° Distance Scale: (m) 0.3 (magnification 0.17X) to 3.OO (ft) 1 to 10.oo Focusing: Helicoid Minimum aperture: f/22 .A Diaphragm: Automatic Filter Size. 52mmHood: BW-52A Cap: C-52 Function: Auto Aperture, Full aperture metering (AE operation when used with ALL Canon automatic SLR cameras. Length x max. diameter: 46mm x 63mm Weight: 245g