I recently bought a pin hole lens for my Nikon D850. It has a variety of sizes of pinholes with a ring to rotate to switch between them. (see below for a look at the lens/camera) The pinhole concept predates photography … going back for its roots to the camera obscura. One of the interesting features of pinhole photography is that the depth of field is “infinite”…. everything is ‘in focus’. Of course, the focus isn’t as sharp as one gets with a lens camera and high resolution sensor (or film). Longer exposure times are required… since the size of the opening is so small. You are effectively using a very large “f-stop”. Therefore, a tripod is necessary. The top image of the ferry is a 5 second exposure, for instance.
I had a couple of different pinhole cameras that I had made in the past. One was an assignment for my high school photography class. These days you can buy various pinhole cameras … and spend up to several hundred dollars … some are very nicely made wood boxes. With those, you use either sheet film or photo paper and then have to deal with the development, etc. Since I don’t have a darkroom, I opted for trying out the pinhole lens that was designed with the Nikon F-mount.
Because the pinhole leaves the camera interior open to the environment (even if the opening is very small), I opted to put on a UV lens just as a method of keeping out dust. What I found afterwards is that the ‘infinite depth of field’ of the pinhole means that all the dust particles on the filter are also in focus (or nearly so). Interesting learning process! So, if you look carefully at the enlarged image, you will notice all the specks of dust in the sky areas.