The Tamron 28–75mm f/2.8 Di III RXD Lens is built for nature lovers who have a passion for photography. Ideal for Sony E-mount cameras, the lens uses 17 elements in 12 groups. There are three LD and two XR elements to reduce chromatic aberrations, while the three glass molded aspherical elements and the single hybrid aspherical lens limits the distortion occurring at the edges. The ring-type ultrasonic motor ensures noise-free autofocus operation. You obtain pleasant out-of-focus background areas thanks to the 9-blade diaphragm. The lens barrel resists moisture to keep the internal parts safe in inclement weather.
This is the magnifying factor of a lens. Macro lenses will often be described by their “magnification factor”. A lens with a 1:1 magnification factor produces a projected image on the sensor which is the same as the subject.
The individual pieces of glass that form the overall optical construction. Most lenses have between four and eleven elements to bend the light rays to ensure a perfectly formed image appears on the light sensitive surface, such as a film or CCD. The elements are arranged in groups and may be seen in specification sheets as, for example, 6 elements in 4 groups. That configuration may have two single elements and the other four grouped in pairs.