Newbie question for pinhole w 5x7 field camera

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brianentz

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I’d like to get into pinhole photography with my 5x7 field camera but have questions about adjusting the bellows. I get that adjusting the bellows doesn’t alter the focus, but does it alter the field of view or focal length? That is, will moving the rear standard back away from the front change the field of view more from wide angle to telephoto? Or, is there a single ideal distance between the standards for pinhole on a bellows camera and, if so, how is that to be determined?
 

Rick A

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It doesn't affect focus, but does change angle of view between telephoto and wide angle. There is the possibility of retracting the bellows to the point of vignetting. Play with it and have fun.
 

xkaes

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Sounds like you need to read a book on pinhole photography.

Each pinhole has a focal length. That is the distance from the film that will produce the highest resolution / sharpest image (at infinity). The wider the pinhole, the farther away from the film it needs to be to get the best result.

So wide-angle pinholes will have smaller holes.

For example, a 120mm f290 pinhole should be placed 120mm from the film to focus at infinity. If you want something closer to have better resolution, you need to add extension -- just like with a regular lens.

And just like with a normal 120mm lens, the picture angle/angle of view DECREASES as you focus AWAY from infinity. Once you figure out the focal length of your pinhole, treat it like any other lens.

And like real lenses light falls off as you move away from the lens axis. With pinholes, you decide how large the image circle / angle of coverage is by deciding when "too dark" is too dark.

Check out the resources at:

http://www.subclub.org/fujinon/pinhole.htm
 
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DWThomas

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There are two sources for calculations online that I have used: Pinhole Designer and Mr Pinhole.

I prefer Pinhole Designer because it gives more information about what it's doing, assumptions, etc. It's main potential problem is that it's a Windows program and hasn't been updated for newer films in a lo-o-o-ng time. It does run on my Windows 10 system.

The Mr Pinhole thingy is a browser script, so more platform independent. However, I find some of its ideas seem somewhat conservative, and last I looked, there's not much info on what assumptions they make.

Either can provide a starting place. I have done a 4x5 pinhole by making a lensboard for my B&J Press, complete with a shutter. And I have since done some other cameras. Could be I enjoy building the cameras as much as using them! 😄 This link will get you to my lens-less photo efforts in the current millennium. That might give you some ideas.

Edit: The timing of your query leads me to suspect you already know about it, but just in case .... There is a group that has promoted Worldwide Pinhole Photography Day each year for the past twenty years or so. It happens on the last Sunday in April.
 
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Jim Jones

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Considerable study and experimenting over several decades confirm your evaluation of these two pinhole calculators.
 

Jim Jones

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Pinhole photographpy may be less practical than mainstream photography, but it is fascinating. The more you read about it, the more intriguing it may become. I suggest the following links:
https://jongrepstad.com/ Jon has reliable information, including instructions for building what appears a practical view camera.
https://www.google.com/books/editio...dq=inauthor:"Eric+Renner"&printsec=frontcover Eric Renner has spent many decades in intensive research in a wide range of pinhole photography, and made the results available in workshops and books. This book excerpt is an example of how deeply he has studied just one small aspect of the subject. There are considerable differences between all of the four editions of the book. Any of them are valuable to the beginning pinhole photographer.
 

Hassasin

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There is only ONE pinhole to film plane distance for ANY given pinhole size that will give best quality, or ONE optimal distance in other words. Pinhole size is a compromise between light throughput and image quality. The distance to film plane MAY give vignetting if it is too short for the pinhole size, but this is too simplistic a statement anyways.

Image quality will also depend greatly on the quality of the pinhole itself. If cut in a too thick of a material it will effectively be mediocre even, if it is perfectly round.

The mentioned calculators are good enough to get the starting info. But every pinhole made is not exactly the same. So this whole thing about pinhole is:
  • find out what pinhole size you need/want from a calculator
  • find highest quality pinhole made in that size (get exact hole measurement form the maker) or
  • try to make one yourself, but be prepared to fail many times before you get one good enough
  • once mounted on camera, try first images with recommended focal distance and if you see results below satisfactory
    • ensure pinhole is the correct size, and is as round as it can be (scanner can be used to evaluate pinhole quality, microscope is better
    • adjust distance to film plane by a minor amount and take another test photo, then again if needed

Quality of pinhole itself is not easy to achieve without proper tools. So-called laser cut pinholes are OK, but still usually need some tinkering to make them better. Material pinhole is cut in ought to be as thin possible while being as rigid as possible.

I want to note that you are going in with a 5x7 size. This has potential of giving great quality images, but it is expensive for a fresh entry into pinhole. I would suggest to start with a roll film holder to get a good understanding of what it involves. You do NOT need to change pinhole distance for the smaller format, go with calculator to get it all set up for 5x7, but then do the early images on a roll film.

In the end a small hole placed somewhere in front of the film WILL produce an image with long enough exposure. How satisfactory that image will be is another matter.

The devil is in the detail, and that is where matching it all as best as possible, through exact pinhole measurement, pinhole quality examination, and testing for optimal distance to film, that gets superior results. That is IF that is the desire. Some call low quality pinhole images ART anyways.
 

MattKing

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There is only ONE pinhole to film plane distance for ANY given pinhole size that will give best quality, or ONE optimal distance in other words.

It is even more complex than this, because there are enough competing factors when it comes to determining "quality", it is actually a question about which of those factors one is emphasizing, before determining what combination of distance and pinhole size to use.
The available calculators give good results.
 

Hassasin

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It is even more complex than this, because there are enough competing factors when it comes to determining "quality", it is actually a question about which of those factors one is emphasizing, before determining what combination of distance and pinhole size to use.
The available calculators give good results.

The issue is complex, true, but there is still only one distance to give maximum resolving ability. That distance can only be determined by testing. This is due to factors that are not possible to account for in any existing formulas, in addition to impossible to repeat, under customary conditions, pinhole size and its finished quality.

it is similar to DOF vs. actual plane of focus.

Each pinhole has a specific focal plane, just like any lens does. Any calculator will give focal distance within a ballpark, which by chance might be exactly correct, but not likely.
 
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Hassasin

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It doesn't affect focus, but does change angle of view between telephoto and wide angle. There is the possibility of retracting the bellows to the point of vignetting. Play with it and have fun.

It affects focus big time. It is the reason why optimal pinhole to film distance is so important. At the same time that is a fixed distance for any pinhole size given, all irrespective of film size used.
 
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MattKing

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The issue is complex, true, but there is still only one distance to give maximum resolving ability.

To give one example of additional complexity, different sizes of pinhole or different pinhole to film distances will be optimal for different wavelengths of light. One of the ways of improving resolution is to either filter out a bunch of different wavelengths, or use film with limited spectral sensitivity.
This 2008 thread contains a useful discussion of the complexities. Unfortunately some referenced links are no longer current.
https://www.photrio.com/forum/threads/how-to-improve-resolution-in-pinhole-camera.35133/
 

Hassasin

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I’d like to get into pinhole photography with my 5x7 field camera but have questions about adjusting the bellows. I get that adjusting the bellows doesn’t alter the focus, but does it alter the field of view or focal length? That is, will moving the rear standard back away from the front change the field of view more from wide angle to telephoto? Or, is there a single ideal distance between the standards for pinhole on a bellows camera and, if so, how is that to be determined?

Just to summarise my posts and maybe some more commentary:

  • yes, there is a single distance that is optimal for a given pinhole size, if distance is not correctly set for whatever pinhole size used, results will not be optimal, this is technical best I am referring to
  • once you get the right distance, you will need to make a mark for future use, so you can repeat the setting for pinhole it was set up for
  • in order to measure the distance (starting with what calculators give), it is best to measure internally from front standard mounting plate to ground glass, then compensate that for the actual location of pinhole plate against that front mounting plate, so you end up with distance between pinhole itself and ground glass
  • calculators already mentioned will give good to very good results, key is to ensure that pinhole size used is the one as stated, with purchased pinhole, they are likely close enough to what they say they are, but it would not hurt to check upon receipt, good makers WILL provide actual size of what was shipped (so when you order say a 0.3mm pinhole, what you will receive may say i.e. 0.323 mm or something else, if it only says 0.3 then it is not likely accurate), how far off is still good enough is a matter of desires, taste, and wanting to be as exact as possible
  • some disappointment form what a specific pinhole produces comes from not examining the pinhole and only relying on either "method" used in making it (assuming drill bit used produces that size pinhole, it did not), or pinhole provider's data
  • quality of pinhole is important to get best resolution, when viewed under microscope it is clear what the problem is, edge artefacts that can be significant, lack of roundness, all play part in what can be achieved on film, material thickness is also very important,

Pinhole vs. lens is like an open gate vs. heavily screened one.

Lens corrects what is happening with light rays as they pass through each subsequent element and how they ultimately coincide at film plane.

Pinhole is not capable of doing that, is not correcting for anything, so light rays come through and fall onto film plane as they may. Pinhole size and shape, combined with distance to film plane, determine how it all records on film.

In most basic sense, each tiny part of what makes up each detail of a scene is projected onto film plane as a "cone of light", which as it passes through the hole continues to expand in size until it reaches film plane.

The best resolution is achieved when two neighbouring "cones" are just adjacent, not separated nor overlap[ping. This is where focal distance makes its mark, and cannot be calculated accurately enough, it must be tested and adjusted for (again, from pure technical best standpoint). How important this part is, it is up to each individual to determine. And there are three basic pinholers out there (later on this).

These "cones" also distort in shape as they move away from on-axis position, something that is part of pinhole image projection complexity, and only partially controllable.

Vignetting has two categories: physical one, which is basically not the case with pinhole projection due to very wide angle of view (call it some 120 degrees, even if it depends on several factors and not a fixed value).

Vignetting that does apply to pinhole photography is from light fall off. It may be significant, depending on how all pieces come together in camera design. In order to minimise light fall-off vignetting:
  • pinhole size and corresponding focal distance can be deliberately chosen to project at film plane smaller portion of what pinhole is capable off (so if you have your 5"x7" set up as best possible for pinhole size / focal distance, then use roll film back to make an image say 6x6, you may not notice much vignetting, if any, But then you loose in some other areas by doing so, to much to cover at this point though.
  • use curved film plane instead, which has a benefit of minimising light fall off issue and lessens geometric distortion of said "clones of light" at film plane. Unfortunately it also introduces geometric distortion of its own for most parts of a scene, and of course adds film plane design complexity
  • importance of both of these points is certainly debatable as pinhole imaging is often equalised with vignetted and distorted outcome
in all this, how does one choose which pinhole size to use? Bigger one will admit more light, so exposure times will become much shorter, but resolving ability will drop. So generally the smaller the negative the smaller the pinhole (until diffraction puts a stop to going smaller), so when that negative gets enlarged, things will continue to look acceptable. With larger negatives there is more "room" to sacrifice on recorded detail and allowing better control of what is being recoded (very long exposures directly affect what things look like, some won't even show up i.e some moving objects).

In the end, pinhole photography is a game of compromises chosen to achieve a desired result, Some of it can be well controlled, some will remain in the doldrums of chance.

As you examine pinhole photographs, you will have noticed wide range of outcomes, from hard-to-believe "sharpness" to hardly recognisable detail.

In my view there are three basic types of pinhole shooters:
  • whatever makes an image is what I want - does not matter much how I got there, I have an image, I call it art and stop right there, this group is one that uses pinholes of all kinds of shapes, film plane in all kinds of shapes, as result the outcome is not predictable, some images come out very interesting, some far from it, but it is all a matter of personal approach and subjective seeing, so whoever likes this I can appreciate it
  • get in the main pinhole groove - use recommended pinhole, set it at recommended distance, buy a ready made camera, and shoot away, good chunk of this approach produces good to excellent images
  • tinker till you die - trying to achieve technical limits of pinhole image making, a. partly futile battle, which can be quite rewarding, and with biggest benefit being ultimate understanding of how pinhole does what it does, easy later to depart from it, just like it takes knowing the rules in order to break them
To give one example of additional complexity, different sizes of pinhole or different pinhole to film distances will be optimal for different wavelengths of light. One of the ways of improving resolution is to either filter out a bunch of different wavelengths, or use film with limited spectral sensitivity.
This 2008 thread contains a useful discussion of the complexities. Unfortunately some referenced links are no longer current.
https://www.photrio.com/forum/threads/how-to-improve-resolution-in-pinhole-camera.35133/

Yes, absolutely correct. But without going that far, things can be improved by getting things lined up properly. I am only referring to getting optimal focal distance nailed as best possible.
 

reddesert

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The focal length of a pinhole is just whatever distance the pinhole is from the film. If you put a pinhole on a large format camera and extend the bellows, you're changing the focal length and thus the field of view.

For any focal length pinhole, there is an optimum pinhole diameter that will yield the least-blurred image, which is what Hassassin is talking about. However, you can use a given pinhole at a range of focal lengths and it will work, just be slightly sub-optimal. The equation for optimum pinhole diameter is proportional to the square root of focal length, so it's a slow function of focal length. IOW, if you have a pinhole calculated for focal length 150mm, don't be afraid to use it at 100mm or 200mm pinhole-to-film distance.

I prefer to say that changing focal length and changing pinhole diameter is affecting image quality, not affecting focus. The pinhole has an equal blur circle at all non-macro subject distances. So in the sense that we use "focus" to describe focusing a glass lens, you don't need to focus a pinhole. When you extend the front standard of a view camera with a pinhole, you're changing the focal length, not the focus as you would be with a normal glass lens.

Edit to add: What I said above applies to classical pinholes, not zone plates.
 
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Jim Jones

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There is some latitude in pinhole diameter. Also, we may use other than the optimum on-axis pinhole diameter to improve off-axis performance. Pinholes do exhibit astigmatism off-axis, especially with extreme wide angle photography. This can be reduced by using a pinhole larger than would be optimum for on-axis performance. However, the overall sharpness is also significantly degraded.

These curves represent the smoothed average of two exposures made through four pinholes in a wide-angle test camera with a focal length of 3.5 inches. Solid lines represent radial target lines, broken lines represent tangential target lines. The subject was unevenly illuminated to compensate for the cos 4th power factor. Not graphed was the performance of the .008" pinhole, which was too small to perform as well as the larger pinholes at any off-axis angle. Further research on the curves representing 1.8 and 2.5 Rayleigh Constant would yield practical information useful to some pinhole photographers, but soon after these tests the camera and test chart were given to Eric Renner, who has contributed so much to the pinhole community
 

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xkaes

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IOW, if you have a pinhole calculated for focal length 150mm, don't be afraid to use it at 100mm or 200mm pinhole-to-film distance.

One more reason to have a set of pinholes, just as we have a set of lenses. Why use a 150mm pinhole as a substitute for a 90mm pinhole when you can use a 90mm pinhole? After all, they are a lot smaller and cheaper than glass lenses.
 

Donald Qualls

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they are a lot smaller and cheaper than glass lenses.

If you can handle scissors, a straight pin, fine sandpaper, and the tools to make an ersatz lens board, they're almost free. You can also mount them in card stock socket that will slip fit into the front of a shutter you already have. Convenient for opening and closing vs. tape or similar.
 

Jim Jones

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Yes, indeed! One of the joys of pinhole photography is the designing, fabricating, modifying, and using pinhole cameras. Also, extreme precision is unimportant in practical pinhole image making. A few percent divergence from optimum pinhole size makes little noticeable difference in image sharpness. Consider this: pinhole size as recommended by various authorities varies by more than that. Also, individuals have different preferences.
 

Donald Qualls

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Agreed. The most important qualities of the pinhole are roundness, and thinness of the edge of the hole. Size is third (though you need to know the size to calculate exposure).
 

xkaes

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And fourth is the focal length so you can get the intended picture angle (angle of view) with the best image.
 

Grandpa Ron

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Brian,

As you have discovered there is a lot of theory and design that goes into pinhole optimization and construction.

I have played with pinholes in 35mm, digital and 4x5 cameras, for several years. I have learned the following.
  • The biggest thing you have going for you is your 5x7 format.
  • It allows you a lot of focal length adjustment.
  • You can contact print the image.
  • Pinhole images are "soft focus", a polite way of saying they are blurry. The best PH images are simply less blurry.
  • The best 35mm PH photos suffer when enlarge to 5x7.

Always keep in mind that,
  • Finding the best pinhole size, material, exposure and is a personal opinion and that keeps the hobby interesting.
  • The more you read, the more you will discover that the formulas for light manipulation are very complex, and every author chooses which variable are of lesser importance and interprets what the proper value should be for a given "constant" value.
  • The end result if you will find that the "correct", pinhole size varies from publication to publication based on the authors equipment and judgement. They do however provide a reasonable starting place for your own experiments.
Good luck and post a few of your shots. Here are a couple of mine.
 

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