I am looking to increase depth of field in landscape photography for systems without access to good tilt-shift lenses. I understand the loss of other qualities that contribute to overall image quality inherent in choosing smaller sensor over larger sensor cameras. However, if you set that aside and concentrate solely on maximizing depth of field, it would appear that smaller sensor cameras have an inherent advantage. However, it also appears that the smaller the sensor and the more densely packed the sensels, the wider the f-stop at which diffraction begins to degrade image sharpness, thus negating at least some of the improvement in image sharpness from the greater depth of field. Is there any short-hand way of measuring this trade-off so that one could determine the optimum sensor size/megapixel count (for any given lens/focal length and f-stop) for maximum depth of field without degradation from diffraction? Or is the reality that diffraction denies any significant advantage to the smaller sensors and therefore, for maximizing depth of field, in the end sensor size doesn't really matter?