Topic: pinhole sizes

[xander1027]

today the pinhole camera i bought online came and i just have some questions you could possible help me with. the camera came with 3 different pinhole sizes .2mm , .3mm and .4mm. the pinholes came with a card telling you the f stop  well it reads across .2mm pinhole diameter,  20mm focal length,  100 f number,  and 20 for f22  and then there is a picture of the pinhole this is he smallest of the three. but what i dont get is it says the .2mm pinhole has  f100 and the .4mm has f200. the picture for the .4mm pinhole has the biggest hole. i would think it would be the .2mm with the smaller f stop. is this the way it is with pinholes or is there a misprint. thanks

[CarlRadford]

Suggest you ask ths on f295.com or just look at the pinhole calculators on that site which will answer all your questions for you!

Hope this helps, Carl

[Tammy]

If the focal length stays the same, then the smaller pinhole has the smaller fstop, you are right.  But, if the focal length is 20mm, then 20/0.4mm= f50.  I think 

Anyway, I use this calculator.

 http://www.johndesq.com/dpr/calcdocprintout.htm

[Francois]

If you don't want an on-line calculator, www.pinhole.cz has an excellent version for Windows.

And if you feel like tinkering around, they also have the world's cheapest camera on the site... a Do-It-Yourself kind of thing.