Pinhole Exposure Metering

I'm wondering if it makes sense to spot meter the shadows and adjust exposures and processing based on those numbers, just as you would with conventional B&W photography? I'll be using T-Max 400, with correct adjustments for reciprocity etc. I've been using a Zero Image 6x9 camera with that format. Some of my pictures seem well exposed with little falloff , but others go very dark at one side or the other. I would like to avoid that. Otherwise, what would be the best metering procedure for pinhole?

You can do the math for the pinhole--divide the distance from the pinhole to the film by the diameter of the pinhole and you will have your f/stop. Then meter normally and choose the shutter speed that works with that aperture. Just don't expect most meter scales to go out to f/200 or thereabouts, so some extrapolation will be necessary. Your method of metering shadows sounds good to me, As for fall off, the wider angle you are taking in (the shallower the camera) the more likely the fall off will be obvious.

I bookmarked this site, which also has a good page about making pinhole plates.:

 

Determining Exposure Times for Pinhole Cameras [pinhole.cz]

 

I use a hand-held meter, which only meters from a set exposure time (you can't specify the aperture, and get the time from the meter, as described in the page I linked above). The calculation is very similar though. When I'm pinholing I carry a calculator with my meter to do this.

 

I meter the scene (incident light reading) for an exposure time of one second. That gives me an aperture value; lets suppose that's f/64. I already know my pinhole aperture is f/300. So my exposure time should be 1 second x (300/64) squared = 22 seconds. However, a long time like that probably requires extra for reciprocity failure. That depends on on what film you're using, but for a middling time time 22 seconds that might mean doubling the time.

 

The dark corners don't bother me much: I accept them as the price I pay for a wide-angle view.

So Dustin, you think an incident reading is best? I'll ne using T-Max 400.

I use an incident reading almost always; it's not a particular choice for pinholing. Unless you're photogaphing an unusual scene, a reflected reading should be fine.

 

I usually use slower film than that, to get nice long exposure times. With a simple shutter it's easy to get (say) a ten second exposure accurate, but an exposure of one second might be significantly out; a quarter of a second is more or less impossible.