The optical design increases sideline, light gathering capability for increased “corner brightness.” The DI lenses also include new optical configurations and higher anti-reflection coatings. These measures compensate for another problem identified by Tamron engineers: flare, including ghost images in extremely bright situations.
In order to maximize overall image quality and convenience of operation, the DI series offers other useful features. Depending on the specific lens, at least one type of special glass is used to compensate for optical aberrations and distortion, to optimize color rendition and to focus all wavelengths of light accurately, for sharpness across the entire frame. To minimize weight, the barrels include components of engineering plastics said to “excel in dimensional stability and strength.” The three telephoto models include a bonus: a Filter Effect Control (FEC) ring on the barrel. This ring can be used to rotate a polarizer while the lens hood is attached, a highly convenient arrangement in outdoor photography. Naturally, all of the optical and mechanical amenities are beneficial to any type of camera, making the DI lenses highly appropriate for use in film-based photography as well.
The Tamron 70-300mm f/4-5.6 DI VC is surprisingly good optically. It is merely a little bit less sharp compared to my Nikon 300mm f/2.8 AF-S, stopped down to f/5.6. The Tamron does have a more chromatic peculiar, i.e. color fringing in light-to-dark transitions. Construction wise it is a very typical consumer grade with mostly plastic components, but the lens mount is metal; I believe that sufficient. Concerning vignetting, I captured images of a uniform blue sky with the zoom wide open at 70mm as well as 300mm.
Similar to all other Tamron 70-300mm lenses, the long end is on the slow side at f/5.6. It is not an issue under bright sunlight, but at daybreak and evening as well as indoors, it is frequently necessary to turn up the ISO. In other words, this lens is good for outdoor telephoto photography such as family, children’s sports, and casual wildlife photography. For those who are attracted in a telephoto zoom on a budget, the new Tamron 70-300mm is an excellent choice.
Focal Length 70-300mm
Maximum Aperture: f/4-5.6
Optical Construction: 17 elements in 12 groups
Minimum Focusing Distance: 1.5m/4.9ft
Filter Diameter: 62mm
Weight: 772g/27.5Oz without lens cap and hood
Length: 142.7mm/5.6 inches, 195mm/7.7 inches when zoomed to 300mm
There is one more good news i.e. there is free shipping for all orders. For more items you can visit photogear.com