Yesterday I bought the Canon 24 mm EF-S STM lens, an all-round wide-angle lens, 38 mm in full-frame equivalent. I left it assembled and used immediately as soon as I left the shop. These are the results and the first thoughts. The Canon EF-S 24mm f/2.8 STM is the sharp, compact, and inexpensive lens that every Canon shooter should own. its field of view is just a little bit wider than the 40mm on a full-frame body Check which focus mode you are in. Full Time Manual Focus does not work in AI Servo mode. It is probably because the AF is continually active in AI Servo. Here is what I have noticed with all my STM lenses: In One-Shot Auto Focus, the focus can be fine tuned (Full Time Manual focus) anytime the shutter is half pressed. Good clear and concise answer, thank you. I have been offered money for my pictures in the past so I want to put out the best images I can which is one of the reasons I Canon EF-S 24mm f/2.8 STM Standard Lens for Canon APS-C Cameras. Lens cap (E-52II) and the 6D mkii is a full frame camera with a solely EF mount, you will not be The EF 24-105mm f/3.5-5.6 IS STM also claims four additional stops of shutter speed, and provides full-frame Canon shooters with a cheaper alternative to the 24-105mm f/4L. Canon calls the EF-S 24mm f/2.8 the slimmest and lightest EF-S lens the company has ever produced. The 12mm f/2.8 ED AS IF NCS UMC Fisheye Lens from Rokinon provides a 180º diagonal angle of view on Canon full-frame cameras for an ultra-wide angle, distorted perspective that is useful for architectural interiors, landscapes and creative experimentation in any photographic application. 40mm is a very useful focal length on full-frame, which is why just about all the film compact cameras of the 1960s to 1980s had lenses with focal length between 38mm and 45mm. The half-frame (near enough digital APS-C format) cameras tended to have 28mm lenses though, for a similar field of view. by Bryan Carnathan. Load Comparison Images. The Canon EF 24-70mm f/2.8L II USM Lens is clearly the best performing Canon full-frame-compatible general purpose zoom lens available. It is the best from both an image quality perspective and from an AF speed/accuracy perspective. This lens is very sharp/has excellent contrast across the frame even Full frame 22.8 millimetres (0.90 in) Canon EF-S 24mm F2.8 STM: Prime APS-C 22.9 millimetres (0.90 in) Industar-22 51mm F3.5 Prime Full frame 21.0 millimetres (0.83 in) Industar-50 52mm F3.5 Prime Full frame 20.0 millimetres (0.79 in) Industar-69 28mm F2.8 Prime Half frame 13.5 millimetres (0.53 in) Konica Hexanon AR 40mm F1.8 Prime Full frame HVxWbnB.