The Composer comes with the Double Glass Optic installed.
Double Glass (Multi-coated Optical Glass Doublet) included
Focal Length: about 50 mm
Focus Type: Manual
Aperture Type: Interchangeable, magnetic aperture disks
Apertures: f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22
Minimum Focus: about 18" (45cm) / Maximum Focus: infinity
Size: 2.25"(5.7cm) h x 2.5"(6.35cm) w / Weight: 3.7 oz (104.9g)
No electronic communication between the lens and the camera body
Available in mounts for Canon EF (EOS), Nikon F, Sony Alpha A / Minolta Maxxum, Pentax K / Samsung GX, Olympus E1 / Panasonic Lumix DMC
Automatic light metering is possible by shooting in aperture priority mode for almost all digital and film SLR camera bodies except certain Nikon bodies including the D40, D50, D60, D70, D70S, D80, D90, D100, N50, N65, N70, N75, N80, Kodak 14N and ProN, & Fuji S1, S2, and S3.