I was given an assignment by a magazine to photograph 4 local dentists for a full page ad they are each running. I want to shoot it with the 50 Distagon in their offices. What is the 35mm equivilent to the 50 Distagon? Is it more like 28mm or 35mm. If it is not wide enough (I love the view of my 20mm f3.5 Nikkor) I may get the 40mm for my 500 ELM.