Michael Panfeld
Well-known member
David: I've got a question about out of focus lights as they appear in the bokeh. They can range from perfectly round to triangular, ovoid, and 5-, 6-, or 8-sided. I've read that the number of iris blades determines the shape. I've also read that the shape formed by the iris blades as they come together determines the appearance. Is there a definitive answer? Also, is there a list anywhere of lenses and the resulting appearance (i.e., Cooke Series II = pentagonal shape, Coopke S4 = perfectly round, old Angie zooms = triangular, new Angie zooms = round. etc..) or is there a rule of thumb such as the # of blades = round, 7 blades = six-sided or alternatively, the shape of the iris (scalloped, round, pentagonal, - or the double iris of Super Baltars) that can predict the light shape in the bokeh? Such a list would be very useful in choosing lenses? Thanks