Today, CCD and CMOS detector arrays present excellent features in imaging systems. To investigate the suitability of each technology according to various applications, in this work we have comparatively studied the quality of the images provided by different cameras. To this end we have used the speckle method to determine the modulation transfer function (MTF) at different wavelengths of the visible spectrum for the detectors of a low-cost CCD video camera and of two scientific cameras (CCD and CMOS). For both the low-cost CCD and the scientific CMOS detectors, the differences between the MTF curves intensify as the spatial frequency augments, while the MTF decreases as the wavelength increases. For the scientific CCD detector, the MTF spectral behavior does not show this trend, and the differences between the MTF curves corresponding to extreme wavelengths are not expected to be significant, as opposed to what appears for the scientific CMOS detector.