Bill, You may consider an even older technique: pinhole photography. It has many advantages 1. that you don't have to spend a year's income on buying a lens, 2. that you don't have to spend an additional fortune on buying a couple of 2.0 ND filters for that lens which you won't be able to use anywhere else, 3. that the pinhole gives you infinite depth of field (Ooooops... maybe you wanted to have a nice out-of-focus background against a sharp forefront...), 4. that you can shift your pinhole around to use with any of your camera bodies (Nikon F5, Hasseblad, digital, etc...). Seriously, if you are doing long time exposures, make sure you take into account reciprocity failure both at the exposure time and when processing the film. Also, if you have ISO 25 film, go for it... The lower ISO will help shorten the exposure time. I would be reluctant to do multiple exposures unless your tripod was so satble that even an earthqauke would not shake it. Best, Guy > BILL, > > I assume You will be staying with the camera during the time exposure. > > Consider an even -older technique- of covering the lens (darkcloth/hat) to > block 'unwanted subjects' -when they pass by. > > jIMMY >
