Re: Pinhole 9x12cm quest
Jon Grepstad (GREPSTAD@sprakrad.no)
Thu, 09 Oct 1997 12:57:19 +0100
> I'm planning to start 9x12cm sheet film photography.
> Am I right to use formula for hole diameter D:
> SQRT(Focal lenght)
> D= -------------------- [mm]
> 44
>
> Since I have enough quantity of b/w 9x12 sheet film, film holders,
> cassetes, Jobo tank for development of 6 pieces at time, home made
> enlargerer; can someone recomend me a combination of hole diameter
> and focal lenght for this format. I am esspecialy interested is
> there combination that can allow enlargment and by what ratio?
You will find some formulas here:
http://home.sol.no/~gjon/pinhole.htm
Focal length depends largely on your own taste. I prefer wide angles,
e.g. 45-50 mm for 4x5 film to make the most of the infinite depth of
field and rectilinearity at the periphery of the pictures.
Pinhole negatives do not tolerate much enlargement. I enlarge 6x7 cm
negatives 1.8 times sometimes.
Jon Grepstad
gjon@online.no