Lensbaby's new Optic Swap System comprises four optical choices, three of which also come in a kit at a slight discount. All of them take 37mm filters, and the lenses (except the Zone Plate) all use drop-in magnetic aperture disks (included).
• Plastic: 50mm f/2 singlet like the classic Holga and Diana; $35, est. street.
• Single Glass: 50mm f/2 uncoated singlet; $35, est. street.
• Double Glass: 50mm f/2 multicoated doublet, identical to the 2.0 and 3G lens; $85, est. street.
• Pinhole/Zone plate: Flat-field Fresnel lens that toggles between f/19 and f/177; $35, est. street.
• Kit (Plastic, Single Glass, and Pinhole/Zone): $95, est. street.