How do I meter for a double exposure?

[Ric Trexell]

I would like to experiment with making a double exposure where you can see through the people but the building they are by is exposed correctly. I would be using a RB67 Pro S which is the first camera I have ever had that can take double exposures. We have a museum in town that is an old school house. There is an old fashion merry go round in front and I have often thought it would be nice to make my first exposure with a few kids playing in front of the school, then have them step aside and take the second exposure (without moving the camera ofcourse). Would one stop underexposure do it or would you suggest two stops under? I suppose that one could vary the exposure to make the kids less clear or more visible. I looked for books on the subject and no one seems to really have much on it. Have you ever done this and how did you do it? (And how did they turn out?) Thanks. Ric.
P.S. I have posted a pic of the school if I uploaded it correctly. (It was a color shot with the color removed.)

 

[Vaughn]

The easy answer is to to go ahead and experiment with a roll. Keep notes.

The results will vary, depending on the background. At the same relative exposures, against a dark background the figures will seem more solid than when the figures are against a bright background.

 

[Poisson Du Jour]

Double the base ISO of the film, and meter normally. It's fun twist on otherwise ordinary, everyday photography and can be very rewarding.
If there is a predominance of bright tone in the scene it would be wise to bracket e.g. second exposure markedly less than the first.
Absolute registration of the scene from shot of the scene to the next (focus, position) is critical. If using neg film, latitude will be more generous than e.g. slide film. Don't be afraid to burn up film experimenting, and keep notes of what you are doing. Notes are an invaluable lesson and teacher.

 

[Galah]

I would like to experiment with making a double exposure where you can see through the people but the building they are by is exposed correctly...

I have read that -when making multiple exposures- you divide the total exposure you would use if making a normal "single" exposure by the number of exposures in the multiple exposure. That is,in the case of a double exposure, each multiple exposure is half of what the metering requires for a one only exposure.

As pointed out above, you can most easily achieve this easily by doubling the ISO and using the suggested metering for each of the shots contributing to the double.

Presumably, a very rigid tripod would be most handy.

 

[Worker 11811]

If you mask off half the lens with an opaque piece of cardboard or heavy plastic you can make almost perfect double exposures without a lot of trouble at all.

This is a double exposure I took of me playing cards with myself almost 20 years ago.
http://gallery.me.com/randystankey#100102/Twins&

I used a double exposure mask made by Cokin. It slides right into the filter holder and you can slide it and rotate it right into the position you want. I never cared much for the Cokin filters but this mask was in the kit when I bought it. It was the only part of the kit I really liked playing with.

There are a few tells in that picture but it is good enough to make people do a double take before they figure it out.

 

[pgomena]

A one stop underexposure halves the light reaching the film. Two exposures at one stop underexposed = proper exposure. Two stops underexposed would require four exposures.

Peter Gomena

 

[Ric Trexell]

Thanks for your ideas.

To all that responded, thanks. I tried to view the picture of you Randy but I guess my browser is too old or something. I'll try again. That would not be what I wanted though as I want to be able to see through the people. That was a good idea to just meter at twice the ISO of the film, and to increase the exposure by the number of exposures one wants to make. I know that keeping the camera rock solid would be a problem and I was thinking that using my camera on 'T' and covering the lense might be the best bet. For that I could pick an exposure of say 10 seconds, expose for 5 seconds, then hold a cover over the lense while the subjects moved away. Then remove the cover for 5 seconds and only cover it again when I took it off 'T'. That might present less movement than cocking the shutter and hoping the camera didn't move. Ric.

 

[Worker 11811]

I tried to view the picture of you Randy but I guess my browser is too old or something. I'll try again. That would not be what I wanted though as I want to be able to see through the people.

The MobileMe gallery uses a lot of JavaScript for navigating the pages and displaying images. If your JavaScript isn't turned on, isn't working right or is out of date (e.g. old browser) you might not be able to see it.

This image comes via Photobucket instead:

(Clickable thumbnail.)

 

[Ian Grant]

A one stop underexposure halves the light reaching the film. Two exposures at one stop underexposed = proper exposure. Two stops underexposed would require four exposures.

Peter Gomena

Not quite, that can lead to slight underexposure, it's a case of 2+2 doesn't equal 4 perhaps only 3.5, so aim for slight overexposure of about 1/2 a stop.

Ian

 

[pentaxuser]

This post is "stretched" lengthways and doesn't fit my page. All the other posts do. What has happened?

pentaxuser

 

[Ian Grant]

This post is "stretched" lengthways and doesn't fit my page. All the other posts do. What has happened?

pentaxuser

It maybe the attached image, it happened in the old version as well

Ian

 

[pgomena]

Yes, Ian, you are correct that four exposures won't quite make a correct exposure at 2 stops under. Close enough for classwork, but not technically correct. I'd make 5 just to be sure.

Peter Gomena