I'm not really sure what you were asking then Philip. Measuring image scale in arcsec/pixel, what I said above is correct - for a given chip, the longer FL will give a higher per-pixel resolution. The speed (f/ratio) determines the rate of photon accumulation per unit area (pixel), not the aperture.
But it seems like you were already well equipped to answer your question, so I suspect you were after something else. Could you re-clarify?
