With the exception of its renowned 90mm Macro, Tamron is mostly known as a company that makes zoom lenses. It's aiming to change that reputation with a pair of new prime lenses that have some features that set them apart from first-party options from Canon, Nikon, and Sony, and also from its largest third-party rival, Sigma.

The two lenses are actually very close in focal length. There's a moderate wide-angle prime, the SP 35mm F/1.8 Di VC USD, and a true standard angle SP 45mm F/1.8 Di VC USD. But there's a bigger difference between the two lenses than a single digit implies. When paired with a full-frame camera, a 35mm lens covers a moderate wide angle, while a 45mm matches the diagonal dimensions of the sensor almost precisely for a true standard angle field of view. The lenses can also be paired with APS-C cameras, where they'll cover roughly a standard angle (52.5mm) and short telephoto (67.5mm) field of view, respectively.

And there's the minimum focus distance. The 35mm lens actually focuses a bit closer, to 7.9 inches (0.2 meters), which gives it a 1:2.5 reproduction ratio when—despite not having macro in the product name, it certainly acts in that capacity. The 45mm focuses to 11.4 inches (0.29 meters), which gives it a very respectable 1:3.4 reproduction ratio.

There are some characteristics that the lenses share. Both are optically stabilized using Tamron's Vibration Control (VC) system. The 35mm is rated to 3 stops of stabilization and the 45mm to 3.5 stops. That's a boon when capturing stills in challenging light—you can keep your ISO down to a lower level for a cleaner image, or narrow the aperture for more depth of field, even when you don't have a tripod handy. Each has a 9-blade aperture that closes down into a circular shape when the f-stop is narrowed for smooth out of focus highlights.

They're also cosmetically similar, and the cosmetics are a slight departure from previous lenses in Tamron's SP series. Both have a metal barrel with a silver ring at the base, a large, rubberized manual focus ring, a printed focus scale, and wide, raised switches to toggle focus and stabilization settings. And both lenses use 67mm front filters and include a reversible lens hood. The 45mm is a bit larger, measuring 3.6 by 3.2 inches and weighing in at 1.2 pounds. The 35mm is shorter—it's 3.2 inches by 3.2 inches in size—and a little lighter at 1.1 pounds.

Each lens has the same advanced lens coating, which includes a nano-particle surface structure to improve contrast and reduce flare and ghosting, as well as a fluorine front coat to make the front element easier to clean. And both feature a ring-type focus motor and six years of warranty coverage in the U.S.

I've had some brief shooting time with the lenses on the Nikon D810 and found that the focus is as quick as advertised. We'll need to get the lenses into the lab for thorough sharpness testing, but details are quite crisp, even at f/1.8. Both lenses show a little fall-off at f/1.8 and f/2, but it's by no means extreme, and it shouldn't be an issue in field conditions at f/2.8 onward. I also noticed fairly significant chromatic aberration in the form of purple and green color fringing in high contrast areas of the scene. That's something you can generally correct using software tools, but can be a concern to photographers who often shoot at wide apertures. I'll pay close attention to that potential problem area when working on our upcoming review of the lenses.

Both will be made available in Canon and Nikon mounts and will start shipping on Sept. 29. Sony A-mount versions will follow later, although they will omit the VC system as Sony SLRs use in-body image stabilization. The price for each lens, the 35mm and 45mm, is a very reasonable $599.