Demoex som mest stått i vår monter och endast använts av oss själva. Har aldrig varit ute hos kund. Är i nyskick.
Så här skriver Leica själva:
The zoom range of the fast APO-Vario-Elmarit-SL 90–280 f/2.8–4 follows on directly from that of the Vario-Elmarit-SL 24–90 f/2.8–4 ASPH. Together, these two lenses cover a full range of focal lengths extending from 24 to 280 mm.
The newly developed dual internal focusing (DSD®) concept enables a fast autofocus. Its optical image stabilisation (OIS) compensates for up to 3.5 stops of camera shake.
The AF system of these lenses is fast, precise, and almost silent. They thank their outstanding AF performance figures to the autofocus drive unit they share. These are limited only by the mass of the lens elements moved when focusing, the travel from infinity to the closest focusing distance and, of course, the amount of space available. In order to preserve the compact dimensions of the lenses, the integration of these components must follow an integral approach.
Specialists from the areas of optical and mechanical engineering and electronics worked together in an interdisciplinary team on the development of a unique lens concept based on double internal focusing. This system, comprising two particularly light focusing lenses, allows the construction of particularly small and compact drive systems. In addition to space limitations, the choice of the drive motors is also determined by the AF principle used for focusing.
Several contrast measurements at various focusing positions must be made before the correct direction of motion for focusing can be determined and followed by precise focusing. In this procedure, the focusing lenses must be moved rapidly backwards and forwards in accordance with the speed specifications of the contrast AF system. This requires a dynamic drive system without any play.
In these lenses, the drive units installed are extremely powerful and robust stepping motors with Dual Syncro Drive™. Thanks to these, the entire focusing throw can be traveled completely in fractions of a second. This means that the lenses achieve values that are among the best in the full-frame system segment in terms of speed, precision, and noise emissions.
Of the 23 elements in seven moving groups, seven are made from glasses with anomalous partial dispersion for the minimisation of chromatic aberrations. The movement of the two focusing elements is provided by a newly developed drive concept with linear positioning of the lenses by stepping motors. A special feature of this is that the overall length of the lens does not change when either focusing or zooming.
The lens hood supplied with the lens suppresses undesirable reflections and stray light. The lens also has a removable tripod plate for attaching it to a tripod. Its ergonomic design makes the lens easier to carry by hand and allows the attachment of a lens belt. A lockable rotating tripod collar allows the lens to be fixed at any angle. The collar has detents every 90 degrees for rapid switching from landscape to portrait format.