Photos: Prototypes show Sony SLR lens plans

Sony showed some forthcoming SLR lens designs--and its ambitions for attacking a market dominated by Canon and Nikon--at the Photo Marketing Association (PMA) show last week.

The nonworking models were under glass at the Sony booth, and Sony wouldn't say when they're scheduled to arrive.

The supertelephoto, of unspecified focal length but roughly as large as 600mm models from rivals, is the headliner because such behemoths are so expensive that they appeal chiefly to professionals, not a mainstream market.

A second lens that Sony showed at PMA has a more ordinary 28-75mm zoom range, but like the supertelephoto, is designed for full-frame cameras such as Sony's Alpha A900. Such lenses are larger and heavier because they have to produce an image circle big enough to cover a 36x24mm sensor, not just the smaller ones used in mainstream SLRs from Sony and its competitors. The model has a relatively fast f2.8 aperture suitable for low-light shooting, a feature that also increases lens size, weight, and expense.

To the right is the model of a 30mm f2.8 macro lens for close-up shooting. It's designed for smaller-sensor cameras only, Sony said.

Sony showed three other lenses for its mainstream SLRs: a 50mm f1.8 model, an 18-55mm f3.5-5.6 model, and a 55-200mm f4-5.6 model.

The "fast fifty" lens is an ages-old design for the SLR market offering a wide aperture for low-light shots but no zoom range. The others are common as "kit" lenses bundled with the initial purchase of an SLR.