hi i am new too
just made my own with aluminium can + paper folding thing...
used ISO400 kodak negative film
by trial and error.... my pinhole pointing towards the sun = 1 second...
so it is like... approximately 14 stops under 4/f (smena 8M towards sun = 1/250 + 16mm)
would like to share some images but no links are allowed coz i am new here