Multiple Exposure Question

[LabRat]

But what will the effect (on water) look like??? With enough exposures, it ends up looking murky, as there's only chopped (short) exposures, not enough time to build up proper (normal) highlights, and not enough collective "frames" to have a completed event image... With many exposures, it might start looking like a time exposure, as snapped elements start to join... Or something murky with something foggy over it...

You might as well just get a heavy ND filter, as exposure + reciprocity are easily calculated, as one of the benefits is that in a body of moving water, different flow patterns tend to replicate, so with a long enough exposure, the patterns emerge and become visible...

Actually doing some real tests reveal what the camera/film image "sees", rather than what we (think we) "want"... And do we like what we get???

Test, test, test...

Steve K

[xkaes]

You don't need a calculator -- other than the one you have in your head. Just determine the correct exposure for a scene/subject, as you normally do. Then, determine the number of exposures you want to take. If nothing else, just guess. I first used this approach with a Minolta SLR that had double exposure capability, but a LOT of "double" exposures is a pain -- MUCH, MUCH easier with large format.

Make sure your camera is secure to a steady tripod -- you don't want to waste a lot of time by having your camera move after 50 exposures.

Then start "doubling" your exposures -- as far as you want to go. Every time you double the number of exposures, you simply switch to the next faster shutter speed:

2 exposures = 1 shutter speed change
4 exposures = 2 shutter speed change
8 exposures = 3 shutter speed change
16 exposures = 4 shutter speed change
etc.

Pretty simple. If you run out of shorter shutter speeds, add NDX filters -- BEFORE you start, of course.

Sure, the intermittency effect exists, but it depends on how bright your subject is as well as how many exposures you take. The darker the subject and the more exposures, the more compensation you will need. My experience? Find something more important to worry about -- like being struck by lightning. You are more likely to run out of "a next faster shutter speed" or "time" before you need to worry about intermittency. And even if it is there -- to whatever extent -- you might like the effect. My best results were taken on Long Island Sound, shortly after sunset with Kodachrome 25 and colored filters. I did not even attempt to guess at how much to compensate for intermittency.



The effects will be different depending on how many exposures you take. The more you take, the more it will be like a single LONG exposure, but still will be different. And remember that you can make other changes inbetween exposures, such as filtration changes, which you can't do with a single LONG exposure. Once again, you are only limited by your imagination.

[Jac@stafford.net]

Thanks to all who corrected me. I went so far afield I got lost.

[pjd]

This is exactly what I am trying to achieve. So going back to my initial question, do I have the maths right in order to calculate the number of required exposures

Fixed it Unless you are an American exiled in Doncaster, in which case please accept my apologies.

About the original question, why not make two negatives (one with split exposure) and see if you can spot a difference (in negative density, not in the waves or whatnot). Also check which prints better.

[xkaes]

Here's one that I've used myself many times. I'm at the beach with a bunch of rocks. I can take one exposure at short or long shutter speeds -- at whatever f-stop. With the longer exposures I get more blurrrrr of the waves crashing. Or I can take 64 exposures of the same scene with a short exposure time with the waves frozen at different positions. Completely different effect.

Always willing to drag up a long dead topic, I ran across this shot today -- from an ad -- which shows the effect of multiple exposures versus one long exposure. One long exposure would show the waves as a complete blur. That would be very nice. Here it is with multiple shorter exposures which show the waves frozen in different positions. Also nice. Some people will prefer one over the other, but the point is that the effect/outcome/result is different.



FYI, I have no idea how many exposures were taken. It is not my shot, but I have some similar ones -- also at a (different) beach.

Happy multiple exposing!