Canon has been on a bit of a patent spree in the last few days and its latest idea could be curved diaphragm. A patent filing originally spotted by Egami suggests the Japanese camera giant will implement a new curved diaphragm to match the rounded shape of the lens. In theory the domed shape could save more space in smaller lenses such as the Canon EF 40mm f/2.8 STM Pancake Lens or EOS M lenses.
More recently, Canon patented a new string of pancake zoom lenses ranging from a minimum 10mm focal distance all the way to 55mm. These curved diaphragms might be the key to actually manufacturing collapsible zoom lenses. Still, this domed design leaves a lot of unanswered questions like how it will impact the lens’ bokeh. Normally every piece of glass has a flat iris aperture, where more blades (coupled with good glass) can create rounder bokeh balls with a smooth blurred background. Alternatively, a round aperture implemented with a Tilt-Shift lens might create some truly perspective shifting images if light manages to catches underneath the edges of the diaphragm.
Via Canon Watch