More and more I find my self shooting one of three Sigma prime focal length lenses in the studio… the 50mm f/1.4, the 85mm f/1.4 and the 150mm f/2.8 OS macro. I noticed that zooms were making me a bit lazy. Hey! It’s a lot easier to twist a zoom ring that it is to move a 300 pound studio stand even if it is on wheels. So why do I do it? A couple of reasons. Perspective, perspective, perspective. I shoot full frame Canon cameras. Their normal focal length is almost 50mm. That’s about the same angle of view as we see with our eyes. I use the 50 mainly for full length photographs.