Stability of zoom and fixed lenses used with digital SLR cameras

Consumer grade digital cameras are widely used for close range photogrammetric applications because of the convenience of digital images and the low cost of capture and reproduction. Since the introduction of digital cameras in the 1980s, there has been a strong divide between relatively inexpensive, low resolution, compact digital cameras, and relatively expensive, high resolution, professional digital cameras. In recent years, the improved affordability of SLR (Single Lens Reflex) style digital cameras has increased the use of this class of camera, to some degree displacing professional cameras. Digital cameras are quite often bundled with a consumer grade zoom lens that is designed for the quality of the image, rather than the geometric stability of the calibration. When these cameras are used for photogrammetric applications, it is common practice that a high quality, fixed focal length lens is purchased and used in preference to the zoom lens. Calibration tests were conducted on a range of different digital cameras, all within the SLR class, to ascertain the differences between zoom and fixed lenses when used with these cameras. Analyses are presented that indicate the differences between the two lens types in terms of accuracy, precision and stability and suggest that although acceptable results can be obtained using zoom lenses, a fixed lens provides superior results.