Canon has applied for a patent for EVF optics that will provide a longer eye relief. This of course is necessary for anyone that wears glasses as a short eye relief can cause vignetting and problems in seeing the entire EVF field of view. To be honest, I find the current M5 EVF’s eye relief to be a bit too short for my liking, and most EVFs I find are like this, at least for me.
PROBLEM TO BE SOLVED: To provide an ocular optical system having long eye relief, wide viewing angle, and high optical performance. A first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, a third lens having a positive refractive power, and a third lens having a positive refractive power, which are disposed in this order from the object side to the observation side. And the fourth lens L 4, the focal length and shape of each lens are appropriately set.
Canon Patent Application 2018-124349