Hi I just turned an old agfa folder into a pin hole. What now

[Curlypengling]

Hey everyone I am really new to pin hole. I know it's just longer times and tripods and stuff. I took out all the glass from a agfa isollete or b2 commander and behind the focusing ring but in the focal plane I put a piece of gaffers tape and poked a hole near the middle. Questing how do I go about finding out the aperture and is it critical for the hole to be dead center? I'm doing it for fun so I don't mind if it's alittle experimental but I would like to see a glimpse of some sort of image

 

[Curlypengling]

 

[summicron1]

not having the hole dead center shouldn't hurt anything -- pinhole photography is, by its nature, kind of experimental.

As to how big is the aperture? No clue -- get a really tiny ruler, I suppose -- seriously, you could use a roll to run tests to see what time works in bright sunshine and use that to calculate back. Be sure to allow for reciprocity failure.

 

[Curlypengling]

not having the hole dead center shouldn't hurt anything -- pinhole photography is, by its nature, kind of experimental.

As to how big is the aperture? No clue -- get a really tiny ruler, I suppose -- seriously, you could use a roll to run tests to see what time works in bright sunshine and use that to calculate back. Be sure to allow for reciprocity failure.

Ah ok at work they have fine tools to measure diameters. If I were to find that out how could I calculate the aperture from that

 

[summicron1]

Ah ok at work they have fine tools to measure diameters. If I were to find that out how could I calculate the aperture from that

well, the f-stop is the width of the hole divided into the distance from the film .... An f2 lens has a diameter 1/2 the distance from the lens to the film, so the calculation is similar. For pinhole, most of the commercial holes I have seen work out to about f 138, which with asa 100 film gives me an exposure in bright sunlight of about 2 seconds.

if you google "ideal pinhole for film photography" you will find several sites that tell you how to calculate the ideal hole size, but don't sweat "ideal." As I said, pinhole is by its nature experimental, many wonderful images have been created by punching a hole in foil and having at it.

 

[MattKing]

That looks to be a rather large pinhole - you might have trouble getting usable images with a hole that large.
But it should be fun to try.

 

[Curlypengling]

That looks to be a rather large pinhole - you might have trouble getting usable images with a hole that large.
But it should be fun to try.

Thanks for the Input, the nice this is I can unscrew the focus ring and put in a new piece of material to poke a hole in

 

[Nige]

I like the happy face

there are a number of ways to measure a pinhole including:

• poke a needle of known size in to ensure hole is the needle size
• scan the thing and do some maths based on pixels
  
• if you have an enlarger, put it in the neg holder, project onto the baseboard and measure the circle. Use the enlarger magnification factor (read of column if has a scale or calculate) to determine pinhole size

I use the enlarger method. Whatever method you use, you'll still need to experiment with your exposure times.

 

[pdeeh]

just a wee tip which might be of interest:
rather than use tape (which is going to be difficult to get accurate size holes into and is anyway unlikely to be light-tight), I expect you can find an empty aluminium beer or soft drink can. They're usually blown these days so are thin but not so thin as aluminium foil, and make very nice material for a pinhole.
cut a piece of can to fit where the lens was, and puncture. Sand off the ragged edge of the aperture (the opposite side to where you push the needle or whatever through).

 

[Harry Stevens]

I intend to make a pinhole camera from a very old beat up box brownie, I have found empty sardine tins to be made up from a lovely thin type of metal(aluminum I think) that a tiny needle or pin would love going through..

 

[M Carter]

I converted an isolette I to a pinhole, but I wanted it about 40mm focal length so removed the bellows and stuff - the door can still close, which is cool.

I found an online calculator where you enter hole-to-film distance and hole size, which gave me the FOV (or whatever - essentially what mm lens the coverage is like) and the f-stop.

But I set up a still life and tested film with a range of f-stops and made small prints with a 2.5 filter - to me, that was the best test, it was a "real world" look at how that camera actually exposed the film, and I settled on an aperture for exposure calculations based on what seemed to print the best. And glad I did, my calculations said something like "F90", I found F180 behaved the best.

 

[ced]

I suggest you put a piece of metal (brass shims the nec plus ultra) rather than tape as the tape is probably very "furry" about the edges.
A link to size calculation: http://www.mrpinhole.com/holesize.php
Good luck and post some images.

 

[RalphLambrecht]

Hey everyone I am really new to pin hole. I know it's just longer times and tripods and stuff. I took out all the glass from a agfa isollete or b2 commander and behind the focusing ring but in the focal plane I put a piece of gaffers tape and poked a hole near the middle. Questing how do I go about finding out the aperture and is it critical for the hole to be dead center? I'm doing it for fun so I don't mind if it's alittle experimental but I would like to see a glimpse of some sort of image

the pinhole image will form from the pinhole projecting onto the film,having it close to the center is OK. If it is off center,the image will be slightly off center too.as far as aperture,enlarging or high-res scanning of the actual pinhole will make it easir to measure it.Calculate the f/stop by dividind the focal length(usuallt the distance from the hole to the film plane) by the hole diameter;N=f/d