Have you ever noticed that a focal length covered by one or more of your lenses gets little or no use? Have you found an explanation?
For me, it seems that 50mm is the least used. I used to have a prime which was sold and my 24-105 f/4 L seems really allergic to 50mm 
I find myself always looking for the wider 35mm to increase the environmental impact or for a longer 70/85mm to compress the perspective and reduce dof.



