Nikon D810 Product Manual - Page 449

D AF-Assist Illumination Some lenses may block the illuminator at certain focus distances. Remove lens hoods when using the illuminator. More information on lenses that can be used with the AF-assist illuminator may be found on page 494. A The Built-in Flash The built-in flash can be used with CPU lenses with focal lengths of 24 mm (16 mm in DX format) to 300 mm, although in some cases the flash may be unable to entirely light the subject at some ranges or focal lengths due to shadows cast by the lens, while lenses that block the subject's view of the red-eye reduction lamp may interfere with red-eye reduction. Remove lens hoods to prevent shadows. The flash has a minimum range of 0.6 m (2 ft) and can not be used in the macro range of macro zoom lenses. The following illustrations show the effect of vignetting caused by shadows cast by the lens when the flash is used. Shadow Vignetting More information on lenses that can be used with the built-in flash may be found on page 494. 425