I've been brainstorming for new focus adapter designs.
I've got an idea in mind for these focus adapters with closeable apertures.
Ideally, I would like to have a focus adapter similar to this, with a spring loaded aperture door that stay shut, and has a small knob that you slide over, and then you'd press it down to lock it into the open position.
I've got all the parts made out (in my head lol)
a single disk with lens threads in the center, and another set of thread on the outer diameter
On the top of this disk would be a milled slot where the flat aperture door would sit, with a spring behind it, maybe mill a deeper groove where the spring sits.
Along with a vertical drill hole where when you slide the aperture door back, you pres the knob down into this hole to lock it into position.
Then a separate piece that has the aperture hole, and inner threads that screw onto the top of that disk, keeping everything into place.
Though this top piece would need a milled slot where the aperture door handle would slide back and forth. Wonder how easily the chinese can make everything line up perfectly on these pieces so the milled slot is parallel with the aperture door.