Pinhole recipe

[sandeha]

Take one empty 6.5x9 plate camera (Vag), one shutter mechanism from a busted 127 (Luxette), add a few strips of brass, some copper sheet, nuts and bolts, goo and paint.  Stir slowly over several days ... when ready, add a film back and shoot.

Ecco - the Vageluxe.  Focal length 40mm.



With 6.5x9 Zodel film pack, stuffed and sealed.  This is the smallest pinhole I've been able to drill so far (0.25mm) and it would be luck for me to get a decent circle smaller than that.  

Here's a full negative (5x4" sheet film cut in two) and a tweaked crop.  FP4 in Rodinal.  





The Cylux shutter on the Luxette (1955 ?) had a three-aperture slider (f7.7, 11, and 16) where the pinhole foil now sits.  Speeds of /100, /75, /50, /25, and B, and a flash contact.  There are a couple of shots of the parts 'over there'.  

The first test showed that the camera still needed work; I've since fixed the leak and widened the shutter gate.  Another time I could use the RB67 back, so it'll get some use.

[Gene M]

Very very cool. I've got to dig my PH out.

[sandeha]

Go fer it ! !

(Warning, I don't know what this Emo is supposed to imply.)

[connealy]

That's a great looking camera.  My current one has about the same focal length, and I think the pinhole might be about the same diameter, but I'm not sure why I settled on that.  The calculator on the Lenox Laser  site recommends a .3 aperture at 40mm.  If I can summon up the energy, I may try some different sizes.  Also may yet try one of the laser-drilled pinholes as I read recently at APUG that Lenox has removed the $125 minimum order requirement.

[Glenn Thoreson]

I like that first picture. It has a certain something that makes you want to look at it. The second is just too good. Nice job on the camera!

[sandeha]

Well I do appreciate your kind words, all.  As you'll see here, it's clunky nuts and bolts again, holding the shutter-trip inside - about the limits of my technogrip.  


Turned out that the major light leak was under the dark slide, so I'm looking forward to getting out with the 6x7 back.  And it is WIDE - probably equivalent to a 20mm lens.

On the topic of pinholes, I've been going by John Evans' book Adventures with Pinhole and Home-made Cameras which for different focal lengths quotes as follows:

35mm ......... 0.22mm
40mm ......... 0.24mm
45mm ......... 0.25mm
50mm ......... 0.27mm
60mm ......... 0.29mm
70mm ......... 0.32mm

and so on.  In practice it's probably all fairly arbitrary as to what is really 'optimum', but the scale is very tight.  He actually starts with a 5mm focal length and 0.08mm pinhole, and ends the list with a 1meter focal length and a pinhole of 1.2mm.  He also gives the f-stops and a Pinhole Time Factor (for multiplication) for different meter readings, which is useful.

[jcapodiferro]

Excellent!!!.  I love to see people with the skills and imagination to produce a camera that will produce images such as your example!!! Well done.

[connealy]

I think that you are right about the so called optimum aperture.  There are too many schemes for calculating that to have a lot of faith in any of them.  There are also a lot of variables that can influence results and mask any effect the aperture size may have.  I tried out a new aperture on my pinhole today and can't really see any obvious difference in sharpeness.  The quality of the light, the choice of film and the developer really seem more significant. Of course the other part is that sharpness is really not the point in pinhole images since they are all inherently unsharp.

[Glenn Thoreson]

On the subject of optimum pinhole size: I have run across so many formulas and charts that I don't know what to believe. They're all different. I don't understand any of the math, either, so I just use the old fashioned approach. I close my eyes and guess.

[ImageMaker]

Nothing wrong with closing your eyes and guessing.  If all else fails, you can make another pinhole in ten or fifteen minutes (maybe less than that if you precut the brass squares and leave the needle in the pin vise).

The formula I use is the square root of focal length, then divide by 25, all in millimeters.  That gives 0.010 inch, or 0.25 mm for the 40 mm focal length, just dead on what Sandeha came up with as "smallest practical hole", and seems to agree well with commercially made cameras that produce some really exquisite results.