>>3348760>smallest hole i can make is ~1mmThen you need a long long tube to put the pinhole on, because the focal length for 1mm is 562mm (22.126 inches). It will be a zoom pinhole, with an AOV of only 2.4 degrees. A cardboard mailing tube for maps/posters would work for that.
When I make holes in the foil with a needle, I don't use the entire thickness of the needle. Instead I just barely stick the needle into the metal then sand the back side smooth and blow out/clean the holes of swarf/dust. I make many holes in a row then photograph them in macro mode while they are next to a millimeter ruler. Then I'm able to measure the hole sizes in photoshop and use the one that is as close as possible to the target size. That alone can take an hour or more if I'm unlucky. FYI, if you have a paper clip you can grind one end of the wire down to a point using sandpaper, stone, brick, etc.
I have a macro bellows ($25 from amazon) and made this pinhole cap so I could use it like a zoom lens. The metal strip has different sized holes for different points on the bellows. Thankfully, for these focal lengths, I can use micro drill bits. The focal length range and drill bit sizes I can get for pinholes on the bellows are,
FL (Hole dia)
90mm (0.4mm)
114mm (0.45mm)
141mm (0.5mm)
170mm (0.55mm)
That being said, you can purchase micro drill bit sets off amazon for around $4.99usd and they can be as small as 0.01mm. The D3400, that I own, needs a micro drill bit 0.02mm in diameter which gives me a 22.5mm focal length invasive pinhole and is the closest focal length for a micro drill bit that is usable.
>taking this thrifted minolta 70-210 apart todayGood luck. When to take things apart always photo graph the process in steps. It really helps a lot when putting it back. A video can sometimes help even more when you say some notations too.
