The Lensbaby Composer Pro With Double Glass Optic (For Canon EF) is part of the Lensbaby series of SLR lenses, and offers the same spectacular special-effect results. The refined and enhanced Composer Pro has an all-metal ball that gives you a more exact, smooth focus and tilt control and will retain its position after being bent, which makes it easy to use even with one hand. Simply tilt the lens to a desired angle and then focus with a traditional barrel focusing ring. The Double Glass Optic is a hybrid between a bellows camera and a tilt-shift camera. It allows for selective focusing with SLR cameras. It will bring one area of a photo into sharp focus, surrounded by gradually increasing blur. Effects like blurring, glowing highlights, and subtle, prismatic color distortions can all be achieved without software manipulations. The lens can be bent off-center in any direction for different results. The Composer Pro is compatible with the Optic Swap System--a line of different "optics" that can be interchanged with the Muse and Composer versions. This provides artists with an almost unlimited variety of looks and styles to capture their unique visions. The Composer Pro comes supplied with the Double Glass Optic, which provides the sharpest focus in its range. It offers a tack sharp sweet spot, with minimal diffusion at all aperture settings. No electronic communication is possible between the camera and the lens. All operation is strictly manual. Automatic light metering is possible by shooting in aperture priority mode for almost all digital and film SLR camera bodies. The lens aperture can be changed (f/2 to f/22) by inserting one of the supplied different sized aperture discs. The Composer Pro features a unique manual focus design which requires more rotation to move the optic as you approach infinity. This makes it easier to focus on objects at intermediate and distant depths than regular manual focus lenses.