Tamron says its new 17-35mm (designated Model A037) is current the smallest and lightest lens in its class, weighing 460 grams (in both mounts) and measuring just 90 millimetres (Nikon). Tamron also says it represents a new line of ultra-wide zooms – compared to the existing SP 15-30mm f2.8 model – with an emphasis on optimum portability and increased affordability.
The external construction is weather sealed which is complimented by a fluorine coating on the exposed surface of the front element. The optical construction comprises 15 elements in ten groups which includes four with low dispersion (LD) characteristics to help minimise axial chromatic aberrations. Additionally, two elements are aspherical types – created via the glass moulding technique – which are designed to correct for distortion and spherical aberrations. Tamron’s BBAR-type (Broad-Band Anti-Reflection) multi-coating is employ to reduce internal reflections and hence minimise ghosting and flare.
Autofocusing is performed via an ultrasonically-pulsed drive – which Tamron calls OSD or ‘Optimised Silent Drive’ – which includes a speed reduction gear for more precise control. This is specifically to enhance the focus tracking performance with the higher-speed current-generation D-SLRs. The minimum focusing distance is 28 centimetres which gives a maximum reproduction ratio of 1:4.9 at 35mm. Other features include a seven-blade diaphragm, a minimum aperture range of f16-f22 and a screwthread filter fitting of 77 millimetres diameter. The new ultra-wide zoom is compatible with Tamron’s ‘Tap-in Console’ USB dock which allows for firmware upgrades and certain adjustments to the AF operation.
The new Tamron 17-35mm f2.8-4.0 Di OSD zoom is priced at $999 and the Nikon mount model will be available locally from early September. Tamron lenses are distributed in Australia by Blonde Robot and for more information visit http://www.tamron.com.au