Abstract: A method for correcting distortions in multi-focus image stacks comprising the steps: acquiring a plurality of N colour images with an optical system; wherein each color image encompasses a plurality of pixels; converting each of two successive colour images of the N images into monochrome images; scaling each of the monochrome images to a conveniently M by M image; calculating a geometric transformation and a radiometric transformation of the two successive images, wherein the geometric transformation and the radiometric transformation is determined by a set of coefficients, which are determined by least square matching, and using the determined set of coefficients from each of two successive images, to correct each image sequentially and thereby constructing the multi-focus image by applying the determined parameter set to each of the successive images.