Tamron 70-300mm f/4.5-6.3 Di III RXD for Sony FE - Small Size, Big Performance
Tamron has been on a roll with Sony lenses the last two years, releasing a trio of fast zooms (17-28mm f/2.8, 28-75mm f/2.8, 70-180mm f/2.8), compact primes with superb macro abilities (20,24,35mm f/2.8 2:1), and the worlds fastest all-in-one (28-200mm f/2.8-5.6) - all with a unified 67mm filter thread. Their newest release, the 70-300mm f/4.5-6.3 is said to be the smallest and lightest zoom lens that can reach 300mm. With a versatile focal range, the lens is great for wildlife, sports, pets, telephoto landscapes, and more.

The Tamron 70-300mm comes in at 5.8" long at 70mm, and weighs just 545 grams. While it's not shorter, it's considerably lighter than the Sony 70-300mm, which weights 854 grams, though the Tamron doesn't come with built-in stablization. To save weight, Tamron used a specially treated high-strangth aluminum-magnesium alloy, a first for Tamron, which is said to be a 68% weight savings. The lens design is simple, just with the rest of the lineup, but it is weather sealed. Even with its light weight and small size, Tamron didn't sacrifice on image quality. The lens consists of 15 elements in 10 groups, with a low dispersion element for minimal aberrations. The autofocus system uses Tamrons RXD motor, the same found in the extremely popular 28-75mm f/2.8. Like the rest of the tamron lineup, the lens is compatible with Sony's host of teachnology, including Eye-AF, DMF, and in camera corrections.

The seven blade aperture produces nice bokeh when shooting at the far end of the zoom range, and the minimum focusing distance ranges between 31.5" (at 70mm) and 59.1" (at 300mm). Image quality throughout the focal range is on-par with other Tamron FE lenses. The BBAR Coating used supresses any ghosting and flaring quite well. The resulting images are nice and sharp, and chromatic aberration is barely noticeable. The autofocus doesn't disappoint either, and is able to track subjects moring throughout the frame with precision. Just like the rest of the lenses using the RXD motors, the autofocus is practially silent, which is a plus for videographers.

Digging into details, between 70-120mm when shooting wide open, there is slight softness in the corners, which is to be expected. Stopping down a bit definitely improved corner sharpess in that range. From 120-300mm, corner sharpness is better, even when wide open. The best performance from the 70-300mm is between f/5.6-8. For the most part, when using the camera on a A7 III, or even R III, the slight flaws aren't very noticeable. If you're using a Sony A7R IV, the corner softness will be more noticeable. Most photographers using this lens will be shooting subjects that will be centered in the frame, so corner sharpess may not be a deal breaker like it might be with a landscape focused lens.

Vignetting is definitely present when shooting wide open, but decreases drastically when stopping down. As with most long zoom lenses, the 70-300 does have some distortion present. Barrel distortion is present on the wide end of the lens, and some pincusion distortion is present between 150-300mm. These issues will be easy fixes using lens profiles from Lightroom once it is updated. With only seven aperture blades, any "bokeh balls" present will have a bit of a heptagonal shape to them when you close down the aperture.

When compared to its direct competitior, the Sony 70-300mm, the Tamron definitely has some advantages to it. While it might be considerably lighter, more importantly it is half the price ($549 vs $1,273). This alone will be a determining factor to most people. It may not feel as solid as the Sony, or have the external controls/buttons the Sony has, but the image quality isn't lacking. The corners in the Sony 70-300 may be a little more sharper throughout the zoom range, but when comparing center sharpness - it's essentially a draw, and the Tamron has a slight advantage on the wider end. Even though the Sony is a slightly faster lens (f/4.5-5.6), the out of focus area on the Tamron tends to look cleaner despite it going down to f/6.3 at the far end of the zoom range.

If you're a Sony shooter looking for a quality mid range to telephoto zoom lens that's not going to weigh you down, and more importantly - not break the bank, the Tamron 70-300mm is definitely a lens to take a look at. For more information, and to order the Tamron 70-300mm f/4.5-6.3 Di III RXD, click here.