I was asked by Rudolph Crane, who is developing an autoexposure pinhole camera
, if I might like to try out his AE PinShot device and give him some feedback. It comes in two forms – just the meter by itself or an entire camera with a shutter controlled by the meter. My demons don't allow me to use pinhole cameras I haven't made myself, but I agreed to try out the light meter.
With the touch screen at the top, you can set aperture and distance to the pinhole, select from several films and store three of those combinations. It has an option to override the exposure by a stop or two to accommodate particularly bright or dark subjects that can trick an averaging meter.
An internal servo activates a lever on the side of the device. A clever camera maker could probably rig a way to open and close the shutter with that lever. It also includes an audible tone if you're going to manually operate the shutter. There's an adjustable built in delay so you can do what's necessary before it starts timing the exposure.
You can read all about it's features and adjustments on Rudolph's website.
A key feature is that it continually moniters the light and adjusts the time if the light changes during the exposure. That means it has to be next to the camera pointing at the subject while the shutter is open. Rudolph included a rail to which the meter and a camera can be mounted side by side. I attached that to a tripod mount with my usual combination of tape and rubber bands. It is definitely heavier and clumsier than my cardboard cameras, but it wasn't all that hard to carry it in my backpack and attach it to the tripod.
I chose the Variable Cuboid using the f200 60mm front with Arista.edu 100 so exposures would be slow enough that my poor hands wouldn't introduce an error. The relatively narrow angle would also eliminate vignetting as a variable. The Arista film would reveal if reciprocity failure was included in the film data. I decided I would just rely on the meter and not fuss with compensation. I never checked it against any other meter either.
The negatives seemed be pretty well and uniformly exposed. They may look a little dense but are well within the limits for the kind of adjustment I make to the scans.
Originally built by a German fraternal society right after the fire that destroyed Oshkosh in 1875, this building has also served The Loyal Order of Moose and the AFL-CIO. When I was first figuring out the meter, I had set the f stop to 133. When I decided to use the Variable Cuboid, I forgot to change it so this picture is two stops underexposed. It's noticably thinner than the others, but still showing shadow detail.
After setting to the correct aperture, I was looking for some average scenes. This was the back of the Exclusive Company Record Store for most of the late 20th Century.
Unlike most of the rear sides of the buildings on Main Street, this one looks like it has no entrance, although it used to.
Looking for something for the Fox Valley Photography Group's Minimalism challenge, I thought these tough little trees surviving in the asphalt corner fit the bill.
Another possibility for the Minimalism Challenge. Glass block and windows on Main Street.
A fierce two day snow storm discouraged further exploration. The snow was very fine and driven by significant winds which transformed the lanai into a soft light box.
One morning I had a bagel with cream cheese and Sarah had an English muffin with peanut butter.
The sun finally came out again. Godzilla and Batman guard the kitchen sink.
The sun shining on the snow is the kind of scene that is notorious for tricking averaging light meters.
Sun and shadows on the metal table in the garden.
The back lit pines with some brilliant highlights on the snow seemed like an extreme test.
One of the key features of the device is the ability to adjust the exposure time to accomodate changing light conditions. This started out with the last bit of sun on the back of the house, which set shortly after the shutter was opened.
Attached to one of Rudoph's cameras with the shutter operated by it, I think it would work great. The exposures seemed as good as I could determine myself with a spot meter. It could probably time sub-second exposures a lot better than my clumsy hands. If a device to operate a cable release could be driven by that servo, I could see people with large format cameras interested or even with other commercial medium format pinhole cameras with cable release options. Being able to just open the shutter and walk off without having to worry about closing the shutter on time is an attractive feature. The constant adjustment to lighting conditions could be very useful on a partly cloudy day where a sunbeam could suddenly appear during your originally long exposure.
The 60mm front on the Variable Cuboid has a .3mm hand-drilled pinhole on a continuously adjustable rising front with 15mm of travel above the axis. The Arista.edu 100 was semistand developed in Cafennol.