"Here is my effort for 'World Pinhole Day', an abstract of bluebells in my garden. I used a double curved slit with the second slit spaced away from the first. This makes for very unpredictable results, so it was good I was shooting digital."
"Nikon DSLR with double curved slit. One curved slit on the lens throat and the second curved slit approx 40mm in front."