I want to make a another recessed pinhole cap, but I need something that is basically a square funnel. If I had a plastic welder, I could whip one up in a half hour. Can anyone here think of something that can be used for this purpose? It needs to be square so that it can have the largest possible FOV and it needs to be a funnel for the same reason. It will actually enter the camera body so far that the mirror will be lifted up in order to get it in. It is intended to get the widest angle possible with a Nikon F-mount. Here's the calculations I have for the pinhole and how far into the camera it will go past the flange,
Invasive into Camera Body to: 27mm
Focal Length: 19.5mm
Image Diameter: 28.8mm
F-stop: f/92
Pinhole Diameter: 0.163mm
An FL of 19.5mm is just about as short as I can get with this ASP-C sensor before the image diameter gets too small and extreme vignetting appears. It just means the hole MUST be dead center.
>>3291091I did the same thing with paper then with sheet metal (great for really long FL and big holes!) then realized foil was awesome for this for the really short FL needed.
>How ...exposure at 100 ISO?I used a tripod for most pinhole pics, but that time is was resting on a brick. I can do handheld pics in full sun, if I'm careful. The shorter the FL the brighter the image can be, if the pinhole is the right size. If I had a mirrorless camera with short FFD I could very easily make the shortest pinhole possible without vignetting in no time at all. I'd be able to take handheld pinhole photos with ease. As a rule, your exposure is normally twice that of your focal length when doing handheld stuff to prevent motion blur. So, 100mm FL means 1/200 exposure. This recessed pinhole cap (pic) is 34.5mm FL so it can do 1/69 exposure (the D3400 can only do 1/60 or 1/80) handheld.
>tape residueUse a citrus-based cleaner and it comes right off like magic. Never tape over lettering, it can pull it off.
>finding middleUse a drafting compass.
