Question about multiple exposures (film)

[StudioDesigntC]

I'm in kind of a bind to do shoot a project for a design class. I wanted to do a multiple exposure scene where I am located in different spots around the room. At first this sounded like a good idea, but they after I thought about it I realized I might not be able to do it.
I'm pretty sure that to make multiple exposures you overexpose each shot according to how many exposures you want on that single frame. So for instance, if I have a reading of f/8 and 1/60 and i wanted to shoot four exposures on one frame, I'd have to change each shot to f/8 @ 1/250. Ok, that would render the scene or background correctly, but am I wrong in thinking that each of my 'bodies' would be overexposed? Or am I just confusing myself?

I'm using a film camera, and will be shooting slides if that matters.

[Gordon]

You are sort of right, except you underexpose by sqrt(number of exposures)

So if you wanted to do a 9 exposure shot, you under expose each frame by 3 stops, to get an even exposure for the final result.

However, moving around, you will be underexposed by that amount.

To get it to work, you'd probably need to light just yourself by a +3 EV light source, for each exposure, then move yourself and the light source around.

Any spill is going to overexpose the background a bit though.

It's a whole lot easier to do digitally :)

[epoh]

Gordon's got it.

another option - shoot at night or in a blacked out room. Set up a remote flash and fire it while you are in several different places - all one exposure.

[StudioDesigntC]

Ah, thanks for clearing that up Gordon. One more question. You mentioned using alight source to light myself + X stops. I have a 580EX flash as well. Would I be able to use the High Speed Sync perhaps to light myself correctly and have the background still -3EV? Or just set the flash to +3EV? I don't use the flash alot, so I'm not totally familiar with it all.

[StudioDesigntC]

Originally Posted by epoh

Gordon's got it.

another option - shoot at night or in a blacked out room. Set up a remote flash and fire it while you are in several different places - all one exposure.

That's a good idea... however I only have 1 flash unit and no cords or wireless set ups
Edit: I will be playing with these in Photoshop, although i'm not very adept at that either, haha. So it wouldn't have to be perfect. I'm just trying to get a feel for it before I start shooting.

[StudioDesigntC]

I just realized, would I be able to take 9 different frames of myself in different places (not moving the camera) with the EV set accordingly (-3EV) and combine them in photoshop (i'll be getting them scanned) to create the ideal exposure?

[venchka]

Enlist the aid of a buddy to fire the flash for you.

As a creative exercise, it would be WAY cool to record what you want on a single frame. That said, you could also shoot X frames and combine in Photoshop as a backup.

How long can you hold a pose? Very long exposures on the order of many minutes won't record rapid movements from pose to pose but will record poses held for 1/X of an exposure of X length. Example: 5 x 5 minute poses = 25 minute exposure. This technique has been used to photograph buildings (interior & exterior) and eliminate vhehicle and pedestrian traffic. ND or polarizer filters can be stacked on the lens to get the long exposures needed.

[Donner]

Originally Posted by StudioDesigntC

I just realized, would I be able to take 9 different frames of myself in different places (not moving the camera) with the EV set accordingly (-3EV) and combine them in photoshop (i'll be getting them scanned) to create the ideal exposure?

If you're just going to use the computer to merge the images, you'd probably want to take all of your pictures with the proper exposure. You'd want to start with one of just the background (assuming it's not just a black backdrop), and then the pictures of your nine places. If you're using photoshop then there is no need to adjust for the effects of a multiple exposure. You don't have to worry about light from your flash adding up if you are just going to cut yourself out of the nine pictures and combine it into a single one.

dt

[venchka]

Yup. That's what it boils down to. A multiple exposures on film problem or just another Photoshop exercise.

[Stephen H]

If you take multiple exposures of yourself in 9 different places using film, with fairly uniform lighting, you will also be transparent and almost invisible in each location. That is, the stuff behind you will be exposed 8 time as much as you are in each location. For what you want, sounds like digital is the way to go.

Or, you would work in a dark room, and use localized flash popped in each location. This might look cool but probably isn't the look you have in mind, either.

Make sure your camera can easily do multiple exposures- not all are set up for it.

[venchka]

Originally Posted by Stephen H

...Or, you would work in a dark room, and use localized flash popped in each location. This might look cool but probably isn't the look you have in mind, either.

Make sure your camera can easily do multiple exposures- not all are set up for it.

Or a flashlight. Paint yourself with light.

Aye! This entire discussion is moot if the camera body won't cooperate. Which brings us back to a long Bulb exposure and intermitant light sources, eithe flash or something else.