I beg to differ unless you're simply converting to grayscale. When I refer to converting to BW, I'm referring to using the channel mixer to achieve the effect of having used colored filters. If you've done it like that, then you should be able to see the loss in quality when viewing the image at actual pixels because of the way you'd be boosting or lowering the three channels that make up your total clarity. In the Rebel XT and the 20D, you can shoot in grayscale mode in the camera with the use of all 3 color sensors, giving you same effect when you use actual colored filters, and you'll have the use of total clarity.