The Sweet 50 is a 50mm f/2.5 selective focus optic with a 12-blade adjustable aperture. This optic combines the popular "normal" 50mm focal length with an easily adjustable aperture mechanism. Photographers can change aperture by simply rotating a ring on the front of the optic. Inspired by one of Lensbaby's first products, the Double Glass Optic, this lens produces the classic Lensbaby look of a sharp sweet spot of focus, surrounded by blur. Photographers can place that sweet spot of focus anywhere within the frame by tilting the lens (compatible with Lensbaby Composer Pro and Composer lenses).Aperture ranges from f/2.5 through f/22. Along with controlling depth of field, aperture controls the size of the sweet spot of focus.