a) Ken Rockwell is a goober. Keep this in mind at all times.
Originally Posted by chip j
b) multicoating on filters will reduce flare due to the filter, not any other flare. All they can do is make the filter less-bad; there does not exist any filter that will give a less-flared image than with no filter. If you want to reduce flare, use a lens hood to make sure there is no direct sun landing on the lens.
If the contrast of the scene is so high that you can't record both shadow and highlight, then yes maybe the lens is poor or insufficiently clean. Or maybe you're just imagining that you can capture a greater dynamic range than is really possible - a white house in sunshine is about EV17 and a dark fence in shade could be EV5 or lower, which is a ridiculous dynamic range. Even with a perfect and flare-free optical system you're going to struggle to capture detail in both the fence and the house even on the best modern negative film. And you won't be able to print it without a massive dodge/burn.