MC Photography

Canon EF 40mm f/2.8 STM

Canon EF 40mm f / 2.8 STM is a real gem. It is a tiny lens with superb optical performance. It weighs only 130 grams. The new STM engine is almost silent and the building quality feels really good. I use this lens in different macro contexts. For example, it works great for mounting backwards with reverse mounting adapters between lens and camera. So-called poor man’s macro. In macro photography with this lens turned in the right direction, i use spacer rings of different sizes to obtain greater magnification.


Lens Specifications

NameCanon EF 40mm ƒ/2.8 STM
Image Circle35mm
TypeWide Prime (“Pancake”)
Focal Length40mm
APS Equivalent64mm
Max Apertureƒ/2.8
Min Apertureƒ/22
Diaphragm Blades7 (circular)
Lens Construction6 elements in 4 groups, including 1 aspherical element
Diagonal Angle of View(Based on image circle)57 degrees
Focus DetailsAF/MF with STM (Stepping Motor Technology)
Front Element Rotation 
Zoom Systemn/a
Closest Focus0.3m / 1.0 ft.
Magnification Ratio0.18x / 1:5.6
Filter Size52mm
Dimensions(Length x Diameter)22.8mm x 68.2mm / 0.90 in. x 2.69 in.
Weight130g / 4.6 oz
NotesOptional lens hood: ES-52