michaela_davidova

<p>Thank you. I use a tin box which I want to convert into the pinhole camera. I want to use 6x9 film in the curved film plane attached with spools inside the box (so I want to calculate the angle of view as well). I bought micro drills and I can drill 0,1, 0,2, 0,3, 0,4 mm.. pinhole so that´s why I try to calculate optimal focal length for the box (the depth is 56 mm).<br> I found the instruction on Instructables http://www.instructables.com/id/Design-and-Build-your-own-Pinhole-Camera/?ALLSTEPS but when I compared the formulas I am used to use for building the cameras the results differ. Usually I was calculating the pinhole according the focal length and using Lord Rayleigh´s formula but since I know my pinhole size I wanted to know if I can use the same formula but for calculating optimal focal length.<br> David, I am not sure if I understand your principle of 0,6 times the diagonal. Do you mean that the pinhole was inserted 90 mm from the sheet of film 4x9? Because according to calculation the 90 mm focal length is not 0,6 times of diagonal, or am I missing something? Thank you</p>

<p>Thank you, David. I am building my own camera. I know size of the pinhole but now I try to figure out how far I should insert my light-sensitive material. Of course, I can experiment and see the result, but it is important for me to understand the principles and mathematics behind.. Anyway, if anybody knows what are the correct formulas or knows some useful links where I can read about it, I will appreciate that. Thank you.</p>

<p>Hello there,<br> I am building pinhole cameras from any boxes and tins. Usually I calculate my pinhole diameter as I know the focal length and where to put the light-sensitive material, so I use the formula of Lord Rayleigh: d = 1,9 sqrt(f*0,00055), where d = pinhole diameter, f = focal length in mm, 0,00055 = wavelength of day light. Recently I bought micro drills so I already know the exact diameter of the pinhole and I would like to calculate optimal focal length. To me it sounds simple, I would just mathematically change the formula to get result for "f". Something like that: f = (d)^2/0,0019855).<br> However, I started to search on the internet and I found out that many pinhole photographers use another formula for counting optimal focal length which is probably called Connors formula: f = (d/0,037)^2, therefore formula for optimal pinhole diameter: d = sqrt(f*0,001369). And here is what confuses me!<br> When I compare Rayleigh´s and Connors´formula the results differ. So my questions are: Are there many formulas for counting optimal pinhole diameter or optimal focal length and it just depends on me which one I choose and which result I prefer and are the formulas I wrote correct? Or in the case I need to know pinhole diameter I use Rayleigh´s formula and in the case I need to know optimal focal length I use Connors´one? Or do I calculate anything wrongly from beginning?<br> Thank you for your help and time. I would really like to know all the mathematics and physics about pinhole photography I am just not the best in maths..</p>