Since there have been a few posts lately regarding long exposures, I'm wondering what exactly is the artistic advantage of using long exposures lasting over fif teen minutes or more, especially with color transparencies?
On a practical issue, what kind of adjustments should be used with a film like V elvia for exposures in terms of filtration and exposure with an exposure of fift een minutes or so? I've used exposures of up to three minutes with Velvia using no filtration and only very modest amounts of exposure increase with my 35mm eq uipment. So far, I have used my camera's suggested meter readings and extrapolat ed the exposure times by metering with a wide open aperature, and it has worked well despite Fuji's recommendations of more drastically increased exposure times . However, I have only used such long exposures due to available conditions, not for any artistic reasons. Similarly, I would like to hear from photographers ac tually use such long exposure times, regardless of what Fuji's tech specs say. M y speculation is that with such long exposures using color transparencies it is the color shift that is desired, despite what some might say regarding 'correcti ve' filtration, though this is speculation on my part. Or perhaps it is the shif ting light position, which would only be an issue during the edge of sundown/twi light or sunrise.
What does such long exposures do for landscapes with foliage lightly moving in a slight breeze? Is a completely windless situation required, or does the movemen t 'average out' and record a sharp image of the 'natural' position of foliage on e would see without a slight breeze?
I've never really experimented with long exposures on my 35mm equipment because of battery drain, but I'm interested if there is any advantage to doing so with my 4 x 5 equipment.