Properly what I should have said is focal length make no difference, i.e. if diffraction is the limit then the number of features per mm that can be distinguished on the sensor (film or digital) is the same at a given f-ratio irrespective of whether the lens is a 600mm wildlife monster or a 20mm wide angle. As the sensitive surface gets bigger more features can be resolved in the image at the same diffraction-limited f-ratio -- hence the advantages of large format. BTW: some of these very high pixel count phones that are coming onto the market are verging on pointless as even with a lens of about f/1.2 the Airy disk is comparable to the Bayer cell in size.James says "...the format makes no difference..." and he seems to know what he's talking about. May I add that it makes no difference on the negative? The degree of magnification needed to make a print must be a factor in how we perceive sharpness. Ian's pictures show how the effect of wind can be much greater than any optical blurring of edges.