A new Tamron SP 90mm f/2.8 Di Macro lens designed for the Sony A-mount camera has been announced. Labelled as model number ‘F017’, this 90mm macro lens is capable of producing 1:1 reproduction (in other words life size reproduction) of small creepy crawlies.
The maximum aperture on the lens is f/2.8 and the minimum capable is f/32. And the angle of view capable on the lens is 27 ˚ 2’ on full-frame systems. The filter thread specification is 62mm. On DX systems the angle of coverage is 17 ˚ 37’.
The lens construction includes 14 elements arranged in 11 groups. Many of the design elements from the old design has been retained in the new lens. This includes one Low Dispersion glass element and two XLD or Extra Low Dispersion glass element. 9 circular diaphragm blades make up for the lens aperture.
The internal elements of the lens adopts a floating mechanism which ensures that the focusing elements lens can be moved while pushing the other group of elements to their best position while focusing is attained. This ensures that regardless of the distance at which you are focusing, the lens is always able to manage nailing the focus accurately.
Auto-focusing is powered by USD (Ultra-Sonic Silent Drive). This technology helps in silent and accurate auto-focus lock 9/10 times. Focus adjustments are also very brisk which helps in overcoming situations of low contrast or lack of texture that can help in faster auto-focusing. In addition to it, the lens incorporates internal focusing technology. The overall barrel length of the lens never changes when the lens is being focused.
The lens also incorporates full-time manual focusing override. This allows the user to switch to manual focusing even when auto-focusing motor is engaged and fine tune the focus.
At f/2.8 maximum aperture and the ability to focus from a close distance of 11.8” the Tamron SP 90mm f/2.8 Di Macro lens can create beautiful out of focus background effects. The lens has been designed keeping in mind that the optical sharpness of in focus elements are never compromised for the background bokeh.
The lens isn’t completely moisture and dust-proof. Having said that, extra bit of sealing has been provided around the switches and dials to prevent accidental water seepage or exposure to dirt and dust. Additionally, the front element of the lens has been given a fluorine coating. Fluorine coating prevents smudges, water and dirt thereby making the lens suitable to be used in less than perfect conditions.
Finally two advanced coating technologies – eBand (Extended Bandwidth & Angular Dependency) and BBAR (Broad-Band Anti-Reflection) ensures that light transmission is maximum and reflection is reduced to a minimum.