Measuring just 68x23mm and weighing around 130g, the Canon EF 40mm f/2.8 STM is a low-profile lens that’s ideally shaped for street photography – and it's also one of the best pancake lenses for Canon cameras. Fitting full-frame cameras, it carries a filter thread of 52mm and comes with the optional ES-52 hood for controlling stray light and reflection. It also provides a viewing angle of 59 degrees, a nice all-around perspective that makes it useful in a huge number of different situations, and especially good if you don’t know exactly what your subjects are going to be doing. As we said, it’s an ideal street companion in lots of ways.
The EF 40mm f/2.8 STM uses a gear-type STM (Stepping Motor) focusing system, which uses gear wheels to drive the focusing action. This means that while on the one hand it’s slower and noisier than the ‘lead screw type’, it can be built much smaller and lighter. This is what gives the lens such a slender profile. One thing that’s worth noting is that manual focusing can only be applied when the camera is switched on, as the tiny focus ring is electronically coupled. Conventional zone focusing or accurately setting the hyperfocal distance are both impossible, due to the lack of a focus distance scale or depth of field markers.
