The Tamron SP 90mm f/2.8 Di VC USD Macro Lens for Sony Cameras features a f/2.8 aperture, Vibration Compensation image stabilization and Ultrasonic Silent Drive that achieves leading-edge image quality while boasting the most compact design in its class.
VC (Vibration Compensation)
VC is Tamron's proprietary image stabilization system. Tamron's VC is a three-coil system, whereby three driving coils activate the shake-compensating VC lens group electromagnetically via three ceramic balls. The VC lens elements are held in place only by contact with the ceramic balls, achieving smooth movement with little friction. This provides a stable viewfinder image with excellent tracking performance. And as the VC lens may be moved in parallel using only the motorized control, the mechanical structure has been simplified, enabling the creation of a more compact lens.
New VC System (Moving Coil Method)
Tamron's original VC image stabilization mechanism utilized a moving magnet system whereby a heavy magnet was positioned near the moving VC lens element. In the new VC unit the positions of the magnet and the coil are reversed, because of this the VC optical lens element is attached to the coil. The new VC mechanism employs a moving coil mechanism with a lightweight coil, and the lighter coil reduces the load on the drive system. Thus, the lighter, more compact new VC unit contributes to the lens's overall light weight and compact size.
The Ultrasonic Motor
In the ultrasonic motor, a piezoelectric element arranged in a ring formation generates ultrasonic vibrations in a metallic ring stator, and the vibration energy is used to rotate a metallic ring rotor that is attached to the stator. The rotation energy is in turn transferred from the metallic ring rotor to operate the focus lens.
What is the eBAND (Extended Bandwidth & Angular-Dependency) Coating?
eBAND Coating, developed by Tamron, is a new coating technique that drastically improves anti-reflection properties. A nano-structured layer (1nm = 1/1,000,000mm) with dimensions smaller than the wavelengths of visible rays of light is deployed on top of multiple coating layers to maximize efficiency.
The nano-structure of the eBAND Coating renders an extremely low refractive index by minimizing the differential with that of air while actively inducing air to its own structure, thus significantly suppressing the extent and degree of reflections.
Through integration with the conventional anti-reflection multi-layer coating technique, attenuating surface reflections utilizing the interference effect between two reflected rays, reflections are well controlled over a broader range of bandwidths and incident angles.
As a hybrid technology between the newly developed nano-structured layer with an extremely low refractive index and conventional multiple-layer coatings, the eBAND Coating provides superb anti-reflection performance, delivering crisp, razor sharp images, and remarkably eliminating the flare and ghosting that can tangibly damage image quality.