The EOS-1D Mark IV features a standard ISO range from 100 - 12800 with an expanded range of 50 to 102400! The combined noise reduction capabilities of the Dual DIGIC 4 Image Processors and Canon CMOS sensor help ensure that even at an ISO setting of 102400, noise is kept to a minimum. This greatly expanded capability provides an increased range of real-world shooting options, especially in available-light or dim situations. A low ISO speed can be useful, for example, when shooting high contrast scenes with fast (e.g., f/1.4) lenses. Blown highlights, such as the shading of a bride’s dress, can be avoided and photographers can use wider apertures to control depth-of-field in ways not possible at higher ISO settings. Additionally, the EOS-1D Mark IV features the Auto Lighting Optimizer (ALO), which automatically adjusts the brightness and contrast during image processing to minimize the need for expensive and time-consuming post-production processing. Auto Lighting Optimizer is available in most shooting modes, including Manual mode and can be applied to RAW images using the included Canon Digital Photo Professional software.