----- Original Message ----- From: earthecho Hello, Frazer Bryant here - New member from England.
Hello Frazer and welcome to the list. >The sheet Film size is 8 and a 1/2 inch X 6 and a 1/2 inch. >(I will be using paper negs.) I have one of those, only mine is 6 1/2 X 8 1/2" !!! Just kidding, Frazer. :-) >Q1 What Dia. pinholes should I use for a) wide angle, and super >wide angle images, and, what would be their corresponding fstops ?. >Q2 What would be the appropriate distances between negative and pinhole >for the above pinholes ?. The above question should probably be formulated in reversed order, in other words, you first want to know what focal lengths constitute super wide and wide, then what diameters "should" be used for them and finally what f/stops would they be. Wide: 120mm to 180mm Super Wide: anything under 120 In general, you could multiply a 35mm format focal length times 6 and that would be the equivalent to 6.5X8.5 format, I.E., 50mm is normal for 35mm formt, the equivalent for your half plate camera would be 50x6 = 300mm The so called "optimum" diameters would be given by: diameter in mm = 0.03679 x SQRT ( focal length in mm) SQRT stands for square root. F/stops could be found by dividing the focal length by the diameter of the pinhole you are using. The appropriate distance distance between pinhole and film plane is the same as the focal length. Download David Balihar's PinholeDesigner at http://www.pinhole.cz/en/pinholedesigner/ , excellent tool to help you with diameters, focal lengths, angles of view, f/stops, etc. Read my articles: http://members.rogers.com/penate/pinsize.htm http://members.rogers.com/penate/diameter.htm Peruse the resources page at Pinhole Visions http://www.???????/resources/ and the one at the World Wide Pinhole Photography Day http://www.pinholeday.org/ Guillermo
