Tamron AF28-300mm F/3.5-6.3 XR Di LD Aspherical (IF) Macro Lens
Digital integration is now available for a popular long-range zoom lens. . . [more]
Surprisingly compact for its extended zoom range and pleasingly light in weight, this new Tamron lens replaces a similar lens without ‘digital integration’. The new model has been designed to provide improved results with digital SLR cameras and its ‘Di’ designation denotes a special optical design. Use of extra-high refractive index (‘XR’) glass and complex aspherical elements have provided optics that match the performance of DSLR cameras and improvements to coated surfaces reduce the chance of ghosting and flare, while minimising peripheral light fall-off. Chromatic aberrations are also curtailed.
The lens is supplied with a flower-shaped lens hood that reduces the effects of angled light that might otherwise affect picture quality. The hood works for all supported focal length positions. Unlike many lens hoods, it is easy to fit for picture-taking and equally easy to reverse when the camera is not in use, thanks to a well-constructed locking system. The ‘petals’ of the hood sit snugly into the lens barrel in the ‘storage’ position.
The test lens was supplied with a Nikon D70 DSLR body, for which it is an excellent match. On the D70, the focal length range changes to 44-465mm. It is also available with Canon EOS, Minolta AF-D and Pentax AF lens mounts. When used on 35mm film SLR cameras it will have its designated 28-300mm focal length range.
On the technical side, the Tamron 28-300mm XR Di lens consists of 15 elements in 13 groups. The diaphragm is nine-bladed to produce a soft blurred background when selective focusing is used (the effect is popularly known as ‘bokeh’, from the Japanese term meaning fuzziness). It focuses down to 49cm across its entire zoom range, allowing photographers to fill the frame with objects roughly the size of an audio cassette.
On test, the 28-300 XR Di lens zoomed smoothly from wide-angle to telephoto and, despite its compact size, the overall length of the lens barrel more than doubled when moving from the wide to the tele position. The zoom is smooth and stable and it is easy to control precisely. The Zoom Lock function, which holds the lens barrel in place when it’s carried vertically, proved handy when we used the camera and lens on a bushwalking trip. You simply retract the lens and lock it in place with a finger-latch. A red bar shows the lens is locked.
Pictures taken with the test lens were pleasing to look at but at no time were we able to capture a shot that could be described as totally ‘pin sharp’ (ie, compared with top quality optics costing much more). Contrast was also slightly reduced, which tended to exacerbate the problem. However, when you take into account the focal length and aperture range the designers have had to cover in this lens, and the price at which it is being sold, it’s remarkable that it does as well as our tests showed.
We obtained the best overall performance at focal lengths between 70mm and 135mm and with apertures between f8 and f11. Within these limits we were able to take shots that looked acceptably sharp when enlarged to A4 size and viewed from an appropriate distance – although we had to boost the contrast with editing software to produce pleasing prints.
Interestingly, rectilinear distortion was surprisingly low for the range of focal lengths covered, with slight barrelling at the wide end and pincushioning at the tele end. Neither would affect the main user group for this lens and we found no noticeable distortion at intermediate positions. Focusing was also generally good, although the AF motor was a tad noisy and manual focusing produced a slight grating noise that was initially disconcerting. However, the lens showed little tendency to hunt, except in low light levels at the 300mm end of its range.
When reading this review, it’s important to view this lens in the correct perspective. In no way should Tamron’s 28-300mm XR Di lens be classified as a ‘professional’ lens and compared with much more expensive optics. By its nature, some significant technical compromises have been required to bring it to market and it’s to Tamron’s credit that they’ve been handled so well. A good choice for cash-strapped photographers who want maximum versatility for their dollar and those who hate changing lenses, it’s also ideal anybody who’s keen on light-weight travel photography. 
Focal length: 28-300mm
Maximum aperture: f/3.5-6.3
Minimum aperture: f/22
Close focus limit: 0.49m throughout the zoom range
Angular field of view: 75 ° – 8 °
Dimeter x Length : 73 x 83.7 mm
Filter diameter: 62mm
Weight 420 grams