That was my favorite camera! My Dad bought the MX and a K1000 somewhere around 1977-78. I used it up until it finally died in the mid 90's. I had the 1.4 50mm, 35mm wide angle, 100mm macro and 70-300mm slide zoom along with the attachable motor drive which made it really comfortable since the body was so small. I was really sad when it finally died.
"Graze in every man's field, but always give your own milk."