Fit models and bodybuilders have one thing in common, very well defined muscles and body shape. That is obvious, really. If the model shoots are for fitness magazines or anything connected to fitness and bodybuilding, the main emphasis will be on the muscles themselves. This means that you’ll need to adapt the light and composition towards that while still keeping the portrait look good.
Getting Your Light Set Up
Unlike glamour, and regular portraiture, where you would probably use one key light, one rim light and a fill light (where most of them will be soft and nice in order to be flattering), here you will need to do lighting quite differently. Depending on which muscle structure you'd like emphasized, you’ll need to adjust the light accordingly. If you want to emphasize the abs, then you’ll need the light to be top down and quite harsh in order to create decent shadows which will accentuate the muscles.