SP – Super Performance series
Performance takes priority for superb image quality
This line of ultra-high-performance lenses is designed and manufactured to the exacting specifications demanded by professionals and others who require the highest possible image quality. The foremost priority is achieving superior performance parameters – high design standards take priority over cost constraints. As a result, Tamron SP lenses feature innovative designs that have established an enviable reputation for excellence amongst demanding photographers.
Form and texture that embodies the high-performance, high-precision qualities of the SP series
This lens features the two gold metal rings that symbolise the SP series, and other design elements that boost its looks. The covering of the zoom and focus rings improve grip. A sleek burnished-black finish on the lens barrel imparts a further touch of refinement. Tamron has also improved the readability of important imprinted information on the lens such as the distance scale and f-numbers.
An innovative combination of optical technologies
The revolutionary use of XR (eXtra Refractive index) glass enables reduction in size while at the same time compensating for aberrations, resulting in the optimisation of overall optical power distribution. Now compactness and light weight are combined with high SP-characteristic performance in this unprecedented “standard zoom” lens. Through an optimal arrangement of four hybrid aspherical elements, compositional capabilities have been maintained while achieving a reduction in the dimensions of the overall optical configuration. The use of three LD (Low Dispersion) elements ensures superb image quality.
Structural innovations enable significant downsizing, reduction in zoom torque and torque fluctuation
Thanks to mechanical innovations that enable a very complex structure to be compressed into a compact barrel, the maximum lens diameter has been downsized considerably to a mere 73mm (2.9″). Handling is enhanced with the reduction of zoom torque and improved torque fluctuation. Tamron has also implemented advancements in manufacturing technology, enabling the production of lighter, stronger and higher precision parts.
Minimum object distance of just 0.33m (13″) over the entire zoom range, and maximum magnification ratio of 1:3.9
This lens boasts a minimum object distance (MOD) of just 0.33m throughout the zoom range. At its telephoto end, macro shooting is available with a maximum magnification ratio of 1:3.9. While the MOD of the earlier SP AF28-105mm f/2.8 changed according to focal length setting (0.5m at 28mm and 105mm, 0.44m at 70-85mm), improvements to the optical and structural design have enabled the reduction in the SP AF28-75mm’s MOD to a constant 0.33m.
IF – Internal Focusing
Focusing elements inside the optical design make for better handling
In many lenses, the front elements move back and forth to alter the focus distance. With an internal focusing (IF) mechanism, the focusing elements are inside the optical design. Because the front lens elements remain static, the lens’ actual length does not change. This provides several benefits both to the image and during photography:
- The barrel is not subject to stray light entering from external helicoids that can adversely affect image quality
- A non-rotating front filter thread makes it easier to use filters such as graduated filters and polarisers
- A flower-shaped lens hood will remain in the correct position to most effectively shield the lens from stray light
- Better balance and more predictable handling because the lens length does not change during focusing
- Generally, a much closer minimum focusing distance throughout the zoom range
- Improved optical performance by minimising loss of illumination at the corners of the image field (vignetting)
- Suppression of other aberrations that become more troublesome at different focusing positions.
Integrated focus cam optimises internal focusing
Tamron’s Integrated Focus Cam is a precision mechanical component that optimises the co-ordinated movement of the Internal Focusing (IF) system with the Multiple Cam Zoom Mechanism. This ingenious mechanism ensures accurate and seamless positioning of all the internal elements within the lens and coordinates them with the external zoom and focus controls.
Useful when carrying the lens/camera over the shoulder
Another original Tamron mechanical engineering concept is the zoom-lock mechanism, which prevents the weight of the lens barrel from extending the lens when carried on the camera pointing downward. This eliminates the danger of accidentally knocking the lens while walking around and enhances responsiveness in the field. Simply zoom the lens out to its widest focal length and use the sliding zoom-lock switch to lock the barrel in place.
Flower-shaped hood is supplied with the lens to shield stray light
Included as a standard accessory, the flower-shaped hood matches the rectangular shape of the image sensor to most effectively block the interference of superfluous light rays entering from outside the borders of the image area, helping to ensure sharp, clear, flare-free images with crisp detail in the shadow areas.