Pinhole Camera Quantitative Reasoning

[shannon_boyle]

<p>I have a film/processing quantitative reasoning assignment for my college level black & white photography class.<br>

I wanted to do something with pinhole cameras. Any idea what I should try to explain about pinhole camera film/processing specifically?<br>

The only pinhole camera I've ever made before was photo paper in a box with a hole in it. Then developing the paper into the darkroom and getting a negative of the image. With the light of the enlarger, I put the negative on top of another piece of paper to get a positive.<br>

While doing research for this assignment you can imagine my surprise when I found out there are actual sophisticated pinhole cameras that use film. What kind of film and paper will I need? How does it work?<br>

Any info will help. Thank you.<br>

-Shannon</p>

[SteveH]

<p>Perhaps, if you could explain what "quantitative reasoning" is to older viewers (and an occasional pinhole user, myself).</p>

[SCL]

<p>The processing of the film, in my experience, is the same. The issue is more film reciprocity which must be taken into account in exposure. There are lots of tables to help you with this. Also, in the exposure side, is the issue of the pinhole size - to determine the effective aperture., and regularity for evenness of exposure. Today many are made by lasers to achieve uniformity both of aperture and focus.</p>

[michael_madio]

<p>Processing is the same. The paper/film doesn't know/care if it's been exposed with a pin-hole. A simple pin-hole body cap on an inexpensive 35mm SLR (digital is okay too) will work.</p>

[jim_jones3]

<p>Your college library should have a copy of Eric Renner's <em>Pinhole Photography</em>. It is the most comprehensive source I know of on the subject. Perhaps more convenient are the f295 and Jon Grepstad pinhole websites. The pinhole camera can be a simple device; a comprehensive study of pinhole photography can consume a lifetime.</p>

[sarah_fox]

<p>... and if your library doesn't have it, they can almost certainly order it in for you through the Interlibrary Loan network. Ask a librarian. ;-)</p>

[shannon_boyle]

<p>Thanks for your responses. Each one was helpful.<br>

In this context, quantitative reasoning is just a fancy way of referring to the science behind how the pinhole lens/film works.<br>

Is there any pros/cons to attaching the pinhole lens to a 35mm manual camera vs the pinhole "camera" made from an empty oatmeal can etc. w/ a sheet of photo paper?</p>

[va3uxb]

<p>Shannon, I think there are some fairly basic pros and cons of using a ready-made 'pinhole lens' on a 35mm camera versus a scratch-built or kit-built or dedicated pinhole camera.</p>

<p>With the ready-made 'pinhole lens' on a 35mm camera body, you have the advantages of using an existing film transport system, existing shutter, and presumably the pinhole adaptor itself has been properly made and probably has a precision-drilled hole. On the downside, you probably have no control over the focal length, or any other aspects of the camera. And IMHO you also aren't going to learn too much about the process.</p>

<p>With a scratch-built pinhole camera, there is a lot more leeway in every aspect of the finished product. You decide the focal length, you decide the film size / format, and you have to learn enough about how and why pinhole cameras work, to get some decent results from it. To me, these are all big advantages. On the other hand, it can be tricky / difficult to get things working right, especially if it is a first try. </p>

<p>My first crack at a pinhole camera was a medium format wood camera with brass fittings, and it was a lot of trial-and-error and head-scratching to get it all working. The end result still isn't much to behold, but I'm proud of it and I got what I wanted in terms of format and focal length. <br>

Some sample pictures: <a href="http://planetstephanie.net/2009/10/12/more-pinhole-pics/">More Pinhole Pics</a><br>

My pinhole camera: <br>

<img src="http://planetstephanie.net/blog/wp-content/uploads/2009/10/front-525x349.jpg" alt="" width="525" height="349" /></p>

<p>More recently I threw together a bit of an oddball, a pinhole camera that uses instant film (Fuji Instax Mini film). It was made in under an hour with plastic, tape, and tinfoil, and was done because I was wondering if it would work. I did a write-up of it here: http://www.lomography.com/magazine/tipster/2011/09/21/pinhole-instax-camera</p>

<p>I guess to summarize my opinion, there's pros and cons whether you just use an adaptor to a normal camera, or you build something from scratch. It depends what the real goal is. If one wants to try pinhole photography then a quick and easy way to do it is with an adaptor to an existing camera. If one wants to really learn about it and get a feel for it, then try building a pinhole camera and go from there.</p>

<p>Cheers!</p>

 

[don_bryant2]

<p>Try this link:</p>

<p><a href="http://www.pinholeresource.com/shop/home">http://www.pinholeresource.com/shop/home</a> </p>

<p>There you find a wealth of information about pinhole photography. And if you have a Nikon or Canon camera you can purchase a pinhole or zone plate body cap. I have the zone plate cap and it provides a unique method to make images.<br>

<a href="http://www.pinholeresource.com/shop/shop?page=shop.browse&category_id=13">http://www.pinholeresource.com/shop/shop?page=shop.browse&category_id=13</a> </p>

 

[SteveH]

<p>I think you could do a lot of "reasoning" with such topics as size of pinhole related to pinhole-to-film (or sensor) distance, and effective f-stop related to size and distance. Also, for film, the long exposures require exposure modifications based on reciprocity failure. I have made pinholes and mounted them on lensboards as the front element of a view camera, so could vary the distance for different effects. Once the image is on the film, there are also development modifications related to the amount of reciprocity failure you encounter. The folks above have nicely outlined many of the available resources. Also check out the World Pinhole Day website for hundreds of samples and other links. http://www.pinholeday.org/</p>

[jim_jones3]

<p>A major advantage of large pinhole cameras over 35mm or digital adaptors is image quality. With optimum pinhole sizes, increasing the film size from 35mm to 4x5 inches with a proportional increase in focal length doubles the sharpness when the prints are made equal in size. This is because the optimum pinhole diameter increases in proportion to the square root of the focal length. Thus, the pinhole for the 4x5 camera is twice as large as for 35mm. The image blur is proportional to pinhole diameter. Since the small negative must be enlarged four times to equal the 4x5 image, its blur will be twice as large.</p>

<p>The above applies to images where sharpness is important. For many pinhole images, a lack of sharpness is acceptable.</p>

[richardsperry]

<p>jim,</p>

<p>So then given time as the only variable. The smaller aperture, pinhole diameter, for a 4x5 is better, correct?</p>

[albert_richardson1]

<p>It would be a good exercise for you to develop your own spreadsheets to perform the calculations built into the various pinhole calculators available in various printed materials and on the web. Consider this to be the "quantitative planning" phase of the project.</p>

<p>I started my own spreadsheet simply to find out how far I could carry out a simple f-stop calculation. This led me down a path that ultimately turned into a pinhole calculator of my own. You can include calculations for optimum pinhole diameters from well respected sources such as Renner. I found ten of these. I also made an inverse of the same ten formulas to find the optimum focal length for a given pinhole size. My reasoning for this was simply that if I bother to pay attention to the result of a leading expert then I had better get the hole drilled right! On the other hand if I can't drill a hole to suit the exact calculation because of some mechanical limitation, then perhaps I might adjust the focal length to the optimum size based on the calculation for the hole I did make.</p>

<p>I also made a calculation based on EV for getting the exposure time right in the field based on an actual light meter reading of the scene.</p>

<p>So there you have it ... spreadsheets to learn the math that goes into building your camera and spreadsheets that help you use it once you have it in your hand. There's a lot to learn here!</p>

<p>Since you are a student this will turn into a great experience for you. You didn't say that your instructor wants you to build a camera, so it shouldn't be a very big deal if you run out of time before you get to the point of buying any film.</p>

[drew bedo]

<p>Hello Shannon,</p>

<p>Think about this:<br>

First: Take a few exposures with some 4x5 camera and a lens. Standardize the subject, composition, exposure processing and printing. This is the control part of the study.<br>

Next: Shoot the same set-up with the same gear only with a pin-hole on the camera set to the focal length of the original lens. This could be as simple as a pinhole plate taped over a drilled lensboard. Extend the front standard till the ground glass-to-pinhole distance matches the nominal focal length of the lens.<br>

Same subject, composition etc . . .only now you will have to adjust exposure and development to approximate the control image.<br>

Photographic principles to discuss are: focal length vs max aperature, depth-of-field (circle of confusion and hyperfocal issues), defractin effects on sharpness, reciprocity, changes in darkroom parameters, the appearance of the final prints (contrast, sharpness, fall-off etc).<br>

This could be quite a good project.</p>

<p>Please let us know what you do and how it turns out!</p>

<p>Cheers,</p>

<p>Drew Bedo<br>

<a href="http://www.quietlightphoto.com/">www.quietlightphoto.com</a></p>

[shannon_boyle]

<p>I am so grateful, all the responses have been so interesting and informative. Each one has helped me in a different way.<br>

Does anyone have any information about pinhole printing techniques?<br>

I printed my image the most basic way. I printed the exposed paper (or in this case I think the proper terminology is negative or paper negative?) in the darkroom like normal. The result was a negative image, which I placed on top of an unexposed piece of paper, the same type I used to get the negative. After exposing and printing, I got a positive image. Even though it wasn't perfect the result still fascinated me.<br>

What are alternative methods? Tricks? Manipulation? Tools?<br>

Any info would be greatly appreciated. Thank you!</p>

[drew bedo]

<p>Shannon: Up-date? What is the current status of this project?</p>