Bob Frost wrote: > Surely the whole purpose of collimated light sources is to achieve > maximum > resolution (I seem to remember this from my light microscopy days many > years > ago).
Actually, not really. You achieve higher contrast and higher apparent sharpness at boundaries with collimated light, but if you equalise contrast by other means, sharpness is pretty much identical. I say 'pretty much' because there are some small-order interactions between film grain edges and collimated light, which leads to enhanced adjacency effects (an optical version of a sharpening filter). Diffuse light bounces around more within the emulsion and tends to creep round grain edges. However the optical ability of the lens system is unaffected and a touch of USM should restore comparability. What's more of a problem is the existence of higher amplitude HF with collimated light excites more grain aliasing through interaction with the sensor Nyquist limit. Regards Tony Sleep - http://www.halftone.co.uk ---------------------------------------------------------------------------------------- Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body
