Faster lenses cost more than slower ones. But are they better? In one area, they obviously are: They transmit more light. A faster lens provides a brighter viewfinder image for easier composing in dim light and allows you to shoot at a lower ISO for better image quality, or at a faster shutter speed to minimize blur due to camera and subject movement. And faster lenses often outperform slower ones. For instance, Canon’s EF 300mm ƒ/2.8L IS USM pro telephoto is superior to its EF 300mm ƒ/4L IS USM pro telephoto not only in lens speed, but also in optical performance, AF performance and weatherproofing. But you pay a price for those benefits. That ƒ/2.8 costs more than three times as much as the ƒ/4 and is much bulkier. Sometimes a slower lens actually performs better. Canon’s EF 70-200mm ƒ/4L IS USM pro telephoto zoom is a much newer design than the esteemed EF 70-200mm ƒ/2.8L IS USM pro tele-zoom, is much lighter and is just half the price. Yet it has a newer and better image-stabilization system, providing four stops of compensation versus the ƒ/2.8’s three stops. The bottom line: If your photography requires lens speed, a faster lens is better. If you don’t require lens speed, a slower pro lens is probably a better choice. The top pro lenses work very nicely for digital as well as film photography. Canon’s pro lenses are designated “L.” Nikon’s have “ED” in the designation. Olympus’ top lenses are the zooms with a fixed maximum aperture and the 300mm ƒ/2.8 super-telephoto. Pentax’s top lenses are the DA* series, especially those with SDM motors. Sigma’s pro lenses are designated EX. Sony’s are the “G” series and the Zeiss optics. Tamron’s top lenses are designated SP. Tokina’s are designated AT-X PRO. |