Buying Pinholes

[waynecrider]

I need a pinhole for a 4x5 and so far have reading two totally different suggestions for the right pinhole size, one by (http://www.lenoxlaser.com/pinholephotography/pinhole_photography_prices.html) saying .018 and the other at (http://www.stanford.edu/~cpatton/pinholemath.htm) saying .314; Any ideas?

Secondly I would like to buy a pinhole so need a sugestion. Pinhole resource has a nice pinhole plate with shutter available but it's a $150, ouch. I have some shutters that work on B or T. Lenox Laser has some at $65. I don't need to take the cheap route and make one, I just need one that is good. Thoughts...

 

[removed account4]

wayne:

many years ago i bought a double set of pinholes (maybe 12 in all ?) from minute aperture imaging / christiansen gallery ( calumet buys them from him too). they were very inexpensive and precise. the guy that runs the business + gallery is very nice and answers emails and phone calls &C.

http://www.foundphotography.com/PhotoThoughts/archives/2005/08/cheap_laser_dri.html

.018 is .018 inches and equiv. to a 160mm focal length.
.314 is .314mm and close to a 75mm focal length.

i have never used the lens plates or shutters that pinhole resource and others sell -- they do look nice though!
i'm sort of low-budget and used a cardboard lensboard with black masking tape holding the pinhole ( shim of metal ) being careful not to tape over the hole ... then a piece of paper with tape on the other side to work as my "shutter" .. kind of primitive, but i've never had a problem (35mm + 4x5).

- john

 

[glennfromwy]

At every resource you will get a different answer on optimum pinhole size. Confusing to the point of giving up, if you let it get to you. Actually, it's not as technical as it sounds. This is one game where close is good enough. I make my own pinholes. It's possible that the ones you can buy would be better than home made, but not by much. My opinion, for what it's worth.

 

[Donald Qualls]

First, Wayne, the optimum size of a pinhole is dependent on the projection distance, equivalent to focal length if you were using a lens. The longer the distance, the larger the hole you need (the hole increases as the square root of distance, so if you quadruple the projection distance, you need a hole twice as large). There are 4x5 pinhole cameras commercially available ranging from around 50 mm up to 150 mm; that would cover a range of optimum pinhole sizes roughly from 0.28 mm (about .011 inch) up to about 0.49 mm (about .019 inch).

Second, different methods of calculating the optimum hole size vary by a few percent; I used the method of taking the square root of the projection distance (in mm), then dividing by 25 to obtain optimum hole diameter (also in mm), which has given me good results and is easy to remember.

I make my own holes, not least because enough .001" brass shim stock to last me ten years or more, and a package of small beading needles, cost me less than the shipping for a minimum order of commercial holes. Using good technique (which you can read about in dozens of locations, if you Google a bit), you can make a hole every bit as good as the commercial ones (even the laser drilled ones) at a cost of about a nickel per hole plus ten to thirty minutes of your time (depending how many times you overshoot the size and start over). A scanner with transparency lid can measure the holes to its limit of resolution (mine gives me .01 mm very neatly), or there are methods using an enlarger with calibrated magnification factor or a microscope with reticle eyepiece. You can get close enough for good results with a dial caliper ($20 at Harbor Freight) and a loupe to compare the hole size to the jaw gap.

And, IMO, it's more fun to make the holes myself and know that the final image quality is dependent on my own craftsmanship.

 

[waynecrider]

First, Wayne, the optimum size of a pinhole is dependent on the projection distance, equivalent to focal length if you were using a lens. The longer the distance, the larger the hole you need (the hole increases as the square root of distance, so if you quadruple the projection distance, you need a hole twice as large). There are 4x5 pinhole cameras commercially available ranging from around 50 mm up to 150 mm; that would cover a range of optimum pinhole sizes roughly from 0.28 mm (about .011 inch) up to about 0.49 mm (about .019 inch).

Second, different methods of calculating the optimum hole size vary by a few percent; I used the method of taking the square root of the projection distance (in mm), then dividing by 25 to obtain optimum hole diameter (also in mm), which has given me good results and is easy to remember.

QUOTE]


I shoot a 135mm lens on my 4x5. I make Ziatype contacts of the negs. The optical 135mm focal length, or maybe even a little longer optical FL like 150mm would be perfect for me. Know I know that the focal length for pinhole size relates to the film to plate distance. According to your formula above, I would use a .46mm pinhole for the 135mm focal length which I guess is .018"?

As regards making my own pinholes, I am going to do that, but think I'll buy one for one of my shutters and then compare my pinholes to that, just to see any differences. Thanks for the help.

 

[Donald Qualls]

Looks like you have it, Wayne.