Stating the obvious, a pinhole is a small circular hole, as could be made with the point of a pin. A pinhole camera meanwhile is a simple camera without a lens but with a tiny aperture (the so-called pinhole). Literally a light-proof box with a small hole in one side. Light from a scene passes through the aperture and projects an inverted image on the opposite side of the box, which is known as the camera obscura effect.
The camera obscura effect is a naturally occurring phenomenon; early known descriptions are found in the Chinese Mozi writings (circa 500 BC) and the Aristotelian Problems (circa 300 – 600 BC). The first known description of pinhole photography is reputedly found in the 1856 book The Stereoscope by Scottish inventor David Brewster, including the description of the idea as “a camera without lenses, and with only a pin-hole”. Sir William Crookes and William de Wiveleslie Abney were other early photographers to try the pinhole technique
An extremely small hole in a thin material can create an image when all light rays from a scene go through a single point. In order to produce a reasonably clear image, the aperture has to be about 1/100th the distance to the screen, or less. The shutter of a pinhole camera usually consists of a hand operated flap of some light-proof material to cover and uncover the pinhole.
If the hole were made bigger then more rays from each point on the subject would pass through the larger hole at slightly different angles causing the image to blur. By making the aperture smaller you block the stray rays of light that would contribute to blur and thus achieve a greater depth-of-field and a sharper image without the help of optics.
I enjoy the occasional foray with a pinhole camera, even building one myself not so long ago and so was annoyed with myself for missing World Pinhole Photography Day (WPPD) in 2019. I was determined not to miss it this year however and had even scouted out a couple of suitable locations on the River Calder ready for the big day. I was it seemed all-set and ready to go.
Of course, April was in the middle of Lockdown and I was shielding, however I was determined not to miss the fun though and so the night before I loaded a fresh roll of Acros II into my wooden Zero Image 612 pinhole camera and dug out a mini tripod. At 7.30am on WPPD morning I was out in my backyard with pinhole camera, mini tripod and light meter to capture my first WPPD submission.
When set to 12×6 my pinhole camera takes five frames (you can shoot six but the sixth is truncated) and as exposure can be hit and miss it is important to think before opening the shutter. I took three compositions, two of which I ended up scanning. The first two compositions were bracketed, two frames at different exposure times, and I used an App on my phone as a light meter having first checked with my handheld meter that it was reading sufficiently accurately. The benefit of the App is that it will display the exposure for an f-stop of 150 which my light meter does not.
After breakfast I processed the roll of film in Perceptol (1+1) and was chuffed to find some decent exposures; indeed, every frame could be darkroom printed if desired and the negatives scanned very nicely on my Epson scanner. My chosen image (above) was uploaded the following morning although I did upload it to my Flickr photo stream on the Sunday afternoon along with one of the other compositions. The third composition I chose not to use as it had not worked as well as I’d hoped but two out of three is not bad!