User manual SIGMA 521

[. . . ] An image sensor element larger than those corresponding to APS-C cannot be used in digital cameras or 35mm SLR cameras. If such an element is used vignetting will occur on the picture surface. If you use SD14 / SD10 / SD9 digital cameras, corresponding angle of view will be 30-85mm. ATTACHING TO CAMERA BODY When this lens is attached to the camera body it will automatically function in the same way as your normal lens. [. . . ] You can adjust the focus by turning the focus ring. (In the case of Four-Thirds cameras it is necessary to switch the camera to MF mode as well) SONY AF and PENTAX AF For autofocus operation, set the camera's focus mode to AF. If you wish to focus manually, set the camera's focus mode to "M" and adjust the focus by turning the focus ring. Please refer to camera's instruction manual for details on changing the camera's focusing mode. The viewfinder of some Nikon AF cameras have indicators to display the focus status. The " " symbol indicates that correct focus has been set, " " indicates that focus is set in front of the subject, and "" indicates that focus is set behind the subject. When this AF lens is used with Nikon AF cameras in MF mode, please adjust the lens' focus until the " " symbol is visible. To avoid damaging AF mechanism, please do not turn the focus ring manually while in the autofocus mode. When operating this lens in manual focus mode, it is recommended that correct focus be confirmed visually in the viewfinder rather than relying on the distance scale. This is due to possible focus shift resulting from extreme changes in temperature which cause various components in the lens to expand and contact. Special allowance is made for this at the infinity setting. In the case of Four Thirds lenses, the function of AF-S mode with MF override is not available. Zooming Rotate the Rubber grip on the zoom ring to the desired position. LENS HOOD A bayonet type detachable hood is provided with the lens. This lens hood helps to prevent flare and ghosted images caused by bright illumination from outside the picture area. Attach the hood and turn clockwise until it stops rotation. (fig. 3) When taking photographs using the built-in flash, it is advisable to remove the lens hood so as to avoid cutting off any of the flash output, which could cause a shadow in the picture. [. . . ] When you use the lens in the rain or near water, keep it from getting wet. It is often impractical to repair the internal mechanism, lens elements and electric components damaged by water. Sudden temperature changes may cause condensation or fog to appear on the surface of the lens. [. . . ]