« on: July 24, 2014, 01:31:42 PM »
40mm on crop will be 64mm angle of view in 35mm. It may be too narrow. If you want to go to the route of Leica lens. 35mm f 2.0 (Summicron) will be a better choice. It is about the same size of the 40mm f 2.0. If the price is too high, then you may try the 35mm f2.8 Summaron.I also have to consider that a new 50mm Canon (F/1.8 IS?) could (will eventually) be delivered, so I'm not sure about having (in the future) two prime lenses with the same focal lenght.
Maybe something different (the 100mms you mentioned, or a good 35mm...).
You may also have to consider that a new 50mm f/1.8 IS will cost $300-$400 and still won't deliver the umph. If I was looking for a really small manual lens for my mirrorless camera, I would consider something like Leica Summicron-C 40mm f/2 (I think it is $500-$800 used).