Touit 2.8/50MnnSmooth and reliable autofocusnThe design of the autofocus system demands an extremely precise movement of certain lens elements. As the mass of the elements or groups to be moved within the optical system differs, various motor types may be installed. The focusing system of the Touit lenses is designed to guarantee robust and smooth autofocusing without any need for compromises or limitations in their optical design.nnInformation: To reach the best compatibility on Sony NEX Cameras (AF in video mode) we highly recommend to use the latest Sony NEX firmware.nn1:1 macro capabilitynThe Touit 2.8/50M lets you capture the smallest things and the tiniest details at their actual size. At its closest focusing distance, subjects sized 15x23 mm fill the frame with an impressive maximum reproduction ratio of 1:1. The imaging performance of the Touit 2.8/50M is just as exceptional at such short distances as it is at medium and long distances. Minimum distortion, outstanding correction of chromatic aberrations, minimal image field curvature and excellent correction of coma and astigmatism allow true-to-life reproduction of any subject, particularly in combination with the high resolving power of modern sensors.nnFull compatibilitynThe ZEISS Touit lenses are designed and constructed specifically for use on Sony NEX and FUJIFILM X Series cameras with APS-C sensors. The lenses are therefore fully-compatible and support all camera functions, including autofocus.nnExcellent resolution and high contrastnRich, vibrant colors are vital to creating a lasting impression. Stray light in the lens, however, would lead to a brightening of the image, which is particularly visible in shadow areas. Image contrast is lowered; the image appears dull and bleached. We combine various, elaborate techniques to reduce unwanted stray light.nnFloating Elements DesignnToday’s camera technologies and high-resolution sensors demand continuous improvement of lens performance. Thanks to the use of the latest floating element design principles, optical aberration effects in ZEISS lenses are reduced to a minimum throughout their entire focusing range. This is achieved by variation of the axial distance between individual lens elements or groups. This adjustment of the lens-to-lens distance is coupled to the distance setting to ensure correct compensation at all times. The mechanical construction of these lenses is extremely complex and they must be assembled with utmost precision – both of which are key competencies of ZEISS.nnIdeal aperture characteristicsnPhotographers want to lead the viewer through their images. Planes with minimum depth of focus are often employed as creative elements. For instance, the background is kept intentionally out of focus to lead the viewer’s eye to the actual subject of the image. The Touit lenses feature a nine-blade iris that closes to create an almost perfectly circular aperture. The effect of this is the creation of a particularly harmonious effect in the out of focus areas of the image (‘Bokeh’).