My main rangefinder is the M3, I recently picked up a Voightlander 35/2.5 lens screwmount. I had a spare M adapter ring for the 12/35/135 which fits on perfectly and the lens couples nicely. Now big skill testing question, do I need to invest in the accessory view finder that fits on the hot-shoe? I do not wear perscription glasses (yet) or can I get away with what I have? Thoughts would be welcome on this matter.