For digital camera systems, transforming from the native camera RGB signals into an intermediate working space is often required, with common examples involving transformations into XYZ or the sRGB. For scene-linear camera signals, by far the most common approach utilizes 3x3 matrices. For color pipelines designed for Rec709 displays, matrix-based input transforms are capable of producing reasonable accuracy in this domain. However, the associated colorimetric errors can become significant for saturated colors, for example those beyond Rec709. To address this shortfall, a novel input color transformation method has been developed that involves the use of two dimensional lookup tables (LUTs). Because the surfaces associated with the 2D LUTs possess many degrees of freedom, highly accurate colorimetric transformations can be achieved. For several cinematic and broadcast cameras tested, this new transformation method consistently shows a modest reduction of mean deltaE errors for lower-saturation colors. The improvement in accuracy becomes much more significant as saturation increases, such that the mean deltaE errors are reduced by more than a factor of three.