DIY Center ND filter?

[Drew Wiley]

Yes, a lawn sprinkler head works great as long as the water is turned on at least! I don't know if that "spinner" concept was ever tried on ordinary wide-angle lenses, however, versus extreme Hypergons. Having fiddled with home-printed ND experiments just for fun, and knowing the frustrations, I'm glad I used real CF's instead for actual shooting. The density ingredient in the real deal glass ones is far finer than any home printer will allow. I don't know if the same technique is used by different manufacturers or not; but it seems like some kind of exceptionally skilled and quite unusual kind of airbrush system was used. I've thumbed my way through the full Edmund Industrial catalog looking for shortcuts, but alas, found none.

[Jim Andrada]

Well, since we're all flying blind here, why not ink jet print a 4 x 5 mask and scrunch it into the film holder sandwiched with the film - basically contact printing the filter together with the image - I'd think this would have no diffraction issues. Old Isaac (Newton as in Newton's Rings)) might give you a problem, though. Wet mounting fluid????? Glass plate??????? DIY vacuum back, perhaps?

But maybe best would be the Photoshop filter suggested above.