The Tamron SP designation is reserved for lenses developed with special emphasis on extraordinary photographic performance. Engineers are free to innovate in an uncommon atmosphere where optical performance comes before price, resulting in lenses that satisfy the demands of discerning photographers. The 90mm f/2.8 macro lens boasts high resolving power and sharp image depiction with ideal background blur, making it the ideal lens for close-up and portrait photography. With emphasis on portability, this macro lens is compact and lightweight. A wide, smooth focusing ring makes delicate manual focusing in the macro mode easy and precise.Di (Digitally Integrated Design) is a designation Tamron puts on lenses featuring optical systems designed to also meet the performance characteristics of digital SLR cameras. The "Di" design is achieved by applying a new optical multi-coating to its element surfaces.The SP 90mm F/2.8 Di enjoys enviable DNA from Tamron's original SP 90mm F/2.8, further refined for the demands of high-resolution digital imaging. Extraordinary 1:1 (life-size) close up capacity, combined with what many consider an ideal portraiture focal length (when used on full-frame DSLR or 35mm SLR cameras) this prime optic was nicknamed "the portrait macro." Equally at home on APS-C DSLRs, rendering a picture angle equivalent of the 140mm lens on a full-frame DSLR or 35mm SLR camera, photographers appreciate the resulting increase in front element-to-subject distance and close-up photography. In addition, this 135mm-like picture angle is well-suited for environmental portraiture. Extraordinary sharpness, striking contrast and a remarkable absence of distortion combine to produce images of exceptional caliber.