July 2011 - "So is it the perfect travel lens? It certain crams in all you’d normally need – with some icing on top as it has more than excellent reach – 300mm equivalent used to be ‘long’ so the 405mm the Tamron offers is a very useful bonus. Find out more about the Tamron 18-270mm Lens here...
Tamron 18-270mm f3.5-6.3 Di II PZD technical details
PZD (PIEZO Drive)
Ultrasonic motors are divided into two categories depending on how the energy that moves the drive is generated: travelling wave motors and standing wave motors. The 18-270mm F/3.5-6.3 Di II PZD employs a newer technology, the PZD (PIEZO Drive), which functions according to the standing wave principle.
A standing wave ultrasonic motor utilizes high-frequency voltage to extend and turn the piezoelectric (piezoceramic) element, thus moving the entire element in a standing wave movement. The metal tip is the contact point of the element to the rotor, and moves in an elliptic motion from the swivelling motion of the moving element. The friction from this motion subsequently turns the rotor. Standing wave ultrasonic motors have the distinct advantage of being faster, quieter and more precise and compact than their travelling wave counterparts.
Di-II
Lenses are designed for exclusive use on digital cameras with smaller-size imagers (also known as APS-C sensors). These lenses are not designed for conventional cameras and digital cameras with image sensors larger than 24mm x 16mm.