The All New Zed 2000

Actually, it's an old Agfa Billy Record. Since it has been reborn as

a pinhole camera, I thought it deserved a new name. I took the lenses

out of the shutter, pulled out the bellows, and clipped out the

associated framework. Cutting a hole in the front plate was tough; it

is solid steel and probably could be put to good use as Humvee armor.

I managed to drill three holes before my one Dremel bit got too dull

to cut. Luckily, that was just enough to insert a carbide wire

hacksaw blade. Finished rounding out the hole with a needle file.<div></div>

I lined the interior with sticky-backed Walmart foamies; that provided a nice black matte finish, as well as blocking any light from entering through the door edges or the drilled-out rivet holes in the front plate. Slapped some more fomie on the front and made a little doughnut sandwich to hold the pinhole up against the shutter's aperture blades. I had to retrieve the film roll holder from my Kodak Monitor where I was using it as a 120 roll film adapter. The 35mm viewfinder is off my Kiev 4A. I'm pretty pleased with the result; it looks like a real camera, it's light tight, and it was built for next to nothing in a couple days.<div></div>

The camera is a work in progress, and I've still got a lot to learn about making pictures through a pinhole. The vignetting has a certain charm, but I think I would soon tire of seeing it in every picture. I'm going to try making the doughnut holes a bit bigger for a start.<br><br><center><img src="http://d6d2h4gfvy8t8.cloudfront.net/3518836-md.jpg"><br><br><i>midday</i></center>

I'm imagining you using it for portraits - and every shot showing gawps of disbelief!

<p>

Do you think a more forward/aft position of the pinhole disk would make a difference to the vignette?

Here's a full frame. I'm pretty sure it is just the hole in the foamie that is the origin of the vignette because of the irregularity. Once I've enlarged the hole, I'll find out if the image is going to clear the edges of the lens mount. I'm also going to paint the inside of the lens mount black as it seems likely that reflections could be a problem.<br>     This is kind of a fast pinhole; in bright sun the correct exposure is a just-doable one second with 100-speed film. I may try some slow film to get a bit more control. Could also be fun to push some fast film and do some hand-held shots.<div></div>

I've got a pinhole body cap for my Spotmatic that lets me shoot hand held at ISO 1600 -- 1/60 in "Sunny 16" condititions, even though I don't have a really effective way to compose because the viewfinder is too dim to see in bright light at f/128. I've gotten good hand holds down to 1/4 second with this setup, BTW -- small amounts of movement matter less, because as long as the motion blur is less than the inherent fuzziness of the pinhole image, it's invisible.

Very nice construction, Mike. I'm surprised at the speed: one second in daylight at ISO 100? My pinhole camera is ~8s with ISO 80, which is much more manageable. On the other hand, in the evening when light is low, it gets a bit tedious waiting for 90s or more to get a shot!

A focal plane shutter would be nice to use with a pinhole; certainly would simplify construction. Thought I was done with buying cameras, but maybe I need just one more.

Well, the nice thing about the speedy pinhole is that I don't have to worry as much about reciprocity failure. The Tower pinhole I built first was 4 seconds in sunlight which was convenient, but indoor shots were up to a minute or two. When I used box cameras often in the past I would carry two loaded with different speed film; I suppose I could do that now with the pinholes.

That vignetting could be caused by the foam, but take a real close look at your pinhole, too. One of the first apertures on my camera was made from tinfoil, and was really irregular; it was as bad as the vignetting you're getting. I ripped it out and switched to a flattened thin sheet of soft alloy from around a tealight (<a href="http://www.ikea.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10101&storeId=3&productId=26118&langId=-15&parentCats=10109*10242)">like these from Ikea</a>). It was a major improvement.<br><br>

Keep us up-to-date... I should really post a picture of my pinhole camera; it'd be the Beast to your Beauty!

Definitely would like to see your camera and some pictures it makes. The pinhole in the Zed 2000 looks pretty smooth under the loupe, though it didn't start out that way. It is one of the "precision drilled" pinholes that I got from the ebay guy. When I looked at it in preparation for installing it in the camera, I was shocked to see burrs around the edges - so much for the "precision" part. I sanded down the stainless steel with 500 and 1500 grit, which got rid of most of the problem, though not all. The last step was inserting the tip of a very small needle and turning it a few times. I felt more confident tinkering with the hole on this one because the stainless is tough stuff and likely more resistant to deformation.

Isn't that vignetting caused because the pinhole is too close to the film to fill out the whole frame?

That's what I was wondering too Steve. Perhaps due to the 6x9 negative size there is a bit of a coverage issue?

 

Pinhole Resource sells precision drilled pinholes for $44/set of 12 sizes. Not sure if that is competitively priced, but the quality might be a bit higher.

 

Doesn't somebody sell pinholes done with lasers? Or does that take all the fun out of it? ;-)

None of the discussions of pinhole angle of view that I have come across provide very satisfying explanations for me as a non-physicist. <a href="http://www.bizarrelabs.com/pin2.htm">The standard formula</a> actually seems to just produce a calculation of how big a portion of the light cone is captured by a given film format. Using that, I get a result for my 35mm pinhole to film distance of 147 deg. on 6x9 (somebody please check my math). It seems like the thickness of the material in which the pinhole is made should determine the diameter of the projected image, as well as the sharpness. I suspect that at normal working distances, coverage is not an issue. When I have run into problems with vignetting in the past, it has been because of an obstruction like the edges of a shutter or lens mount. I'll try to run some film through mine today with the expanded retainers and report back. Meanwhile, maybe we can lure some errant physicist into the discussion.

<a href="http://www.lenoxlaser.com/pinholephotos/">Lenox Laser</a> is the company everyone refers to. I'd love to try one of theirs, but they seem to want a $125 minimum order. That just isn't on my agenda for this sort of project.

Two other observations on the angle of the angle. An infinitely thin pinhole would capture a 180 deg. view, so it seems like we just need someone to do the math. More practically, I think the Zero 2000 has a pinhole to film distance of only about 28 deg. and I don't believe that produces any vignetting.

Sorry, I meant 28<b>mm</b>. I'll shutup for a while now.

That's a shame about Lenox Laser. I'm pretty sure I ordered my two laser drilled pinholes from them last year. I have a 150 and 300 micron ones that I use on an old Holga with great results. You can buy laser drilled pinholes from Edmunds. http://www.edmundoptics.com/onlinecatalog/Browse.cfm?categoryid=677

 

They are more expensive than Lenox, but you don't have that $125 minimum order... I'm in the process of converting an old Spartus Fullvue to pinhole because it has a bulb mode on the shutter and I'm tired of using tape for a shutter...

If the vignetting were coverage, it would have a fuzzier, softer edge than that, especially from a pinhole -- pinholes can cover better than 140 degrees, and loss of coverage usually has more to do with inverse square law light fall-off than a limitation of the "optics". That ragged edge is clearly *something* obscuring the light path. If it were the inner or outer shutter threads, as I thought at first, it would be smooth, so it pretty well has to be the foam.

I enlarged the holes in the foamie retainers for the pinhole, and that got rid of the jagged vignette. However, I now had a smooth round frame that was clearly the barrel of the lens mount -- in a couple frames I could actually see a nice image of the front of the lens mount in the corner of the frame. So, I moved the pinhole in front of the shutter which put it at about the middle of the lens mount tunnel. That did it; I got full coverage of the frame.<br>     This has been a great learning experience for me. In addition to working through the building of the camera, I also learned something about shooting with a pinhole, and with an ultra-wide angle system which I had never tried before. It took me a couple rolls to realize that I needed to get a lot closer to my subject with this kind of camera.<br><br><center><img src="http://d6d2h4gfvy8t8.cloudfront.net/3524289-lg.jpg"><br><br><i>Waiting for Margaret</i></center>

Mike, the formulae I've seen suggest the light falloff from center to edge is governed by a cosine^4th function. That is, there are two factors effecting light falloff:

 

1) The distance from the pinhole to the corners of the image are further away than the distance from the pinhole to the center of the image. The effective focal length increases with off-axis angles of view, so you've got an inverse-cosine square function operating there;

 

2) At off-axis angles of view, the pinhole aperture appears as an ellipse rather than a circle. So the effective aperture size diminishes with angle of view, again at an inverse-cosine square function.

 

The critical question is how much light falloff is acceptable with the light-sensitive materials being used. That's where assumptions about acceptable angles of view come in to play. Shooting color transparency film would be less tolerant of light-falloff than B/W negative material (film or paper).

Wow Mike! That was (is) a great project.

 

Before I read to the end of this thread, I was going to guess that the vignetting was caused by the extremely short focal length for the 6x9 format. I was thinking of the pinhole as having depth front to back that would make it like a short tunnel. As the angle increases (at the edges of the frame) the pinhole itself becomes an obstruction.

 

Well, maybe I'm wrong, because it certainly looks like you fixed the problem. Great image of the tennis shoes BTW.

 

John

I cropped about a mm off either end of the sneaker shot because of some reflections off some scratches on the film gate. Have since painted over those, so should be able to print the whole frame. There is no noticible fall off around the edges, so I'm assuming that I've actually got quite a bit of lee-way on coverage at 6x9. I think the film to pinhole distance is about 38mm. I'd still like to try a laser-cut pinhole if I can find one at a reasonable price, but I'm actually pretty satisfied with the whole setup right now. I do need to work on my shooting technique, though.

I have several dead folders and you have put all kinds of thoughts in my head.<p>Thanks Mike.