Wednesday, January 29, 2020


In our last episode on stereo photography, I noted that 3D effects diminish in impact when you get too far away. With a 6cm baseline between pinholes (based on the dimensions of a human face) on a 45mm 6x6cm format camera, once you’re 15 meters or so away from something, it’s looks no nearer than an object on the horizon.

But what if you had a one meter separation? Now that would take a big stereo camera. Or two regular cameras. Or one camera that you just moved over a bit and made two exposures being careful to keep the camera level and pointing in exactly the same direction. The extension of the baseline beyond normal human dimensions is known as hyper stereo and the method of moving a single camera between two exposures is known as Cha-Cha. I’ve played with Cha-Cha before reducing the baseline to get close up, but only once to extend the baseline to add dimension to subjects farther away and that was only to about 25cm.

I took two film cans and filled them with brass square nuts (1/4 x 20 of course) and tied a piece of butcher’s twine between them so I could quickly define a straight line on the ground.  That line has to be parallel to the film plane. If you make sure the camera is pointing exactly between two tripod legs you can just extend the line those legs define. Take one picture and then, making sure the tripod legs stay completely extended, hence the camera stays level, move it on down the line to the other end and take your second exposure.

Anything moving isn’t going to get rendered in 3D if it’s recorded at all. It was dark and foggy when I did this so I didn’t think moving objects were going to be a problem and the light wasn’t likely to change very quickly.

The internet says that the closest thing your brain can handle is a 1:30 ratio between the baseline and distance to the subject.  The distance across an intersection is about 30 meters so the one meter baseline should work. I decided to use the slightly longer-than-normal 100mm front of the Variable Cuboid so I could fill the frame with the buildings at this distance.

These are set up for crossed eyes (click here for how to do it) and as anaglyphs for those with red/cyan glasses.

I’ve been doing this to possibly include some stereo work in the Oshkosh Public Museum’s “Then and Now” exhibit. Churches are very popular in the stereo views in the museum collection.  This is the First Presbyterian on the corner of Church and Division Streets.

Just down the block another church on Church Street is the former First Baptist Temple. The stereoview in the archive is of their second church on this site. This is the third. The congregation just recently moved to another location and put it up for sale.

One of the archival stereo views is of the Beckwith Hotel, now the New Moon Coffeehouse. You do need a nice flat spot wide enough for both positions of the tripod. It has been snowing for five days so most street corners are a little messy with piles of snow. On the corner of Algoma and Main, the spot I needed to get the picture from included several slushy piles and the camera was tilted both vertically and horizontally between exposures. The right side was composed the way I wanted, but the left was rotated about 5 degrees and tilted down. I rotated, moved and aligned it and then cropped them both to match. I think I got them to match fairly well. I don’t have any trouble getting this one together crosseyed, but it takes a little concentration to get the anaglyph to pop out. This was just across the street and not all the way across an intersection so it also might be a little closer than that 30:1 minimum. I think one issue might be that you have to slightly cross your eyes like you do trying to look at something very close up.

I thought the archive included a view of the opposite corner of Main and Washington, but before Woolworth's built this Art Deco store now occupied by the Exclusive Company. It turns out it was one block down at Main and High. This one only needed about a degree rotation, but it also had to be aligned up and down. It’s actually a few feet nearer than the previous picture but this one is pretty good. It pops into 3D easily and that awning nearly seems to stick out of the picture.

There is a stereoview of Main Street looking North in about 1871 that must have been taken from the roof of a building. Right next to the river, there is a skyway between the hotel and the conference center crossing over Main Street.  It was nice to be indoors with a nice flat floor to work on. Complicating this one were the reflections of structural elements of the skyway in the windows. The street lamp at the bottom is too close, only about 10m away, but if I concentrate on it, I can get it into 3D, but then the rest is out of alignment.

One of the stereo views is of the first Main Street bridge five years after the first permanent wooden bridge was built. The reflections with this one were less of a problem.  I just used the bottom of the skyway window to keep the camera level and parallel. I was close enough to the window so that standing behind the camera, the reflection, or lack thereof, of my black coat filled the frame and eliminated most of the unwanted reflections.

I don’t mean to cause anyone eyestrain.  I think I might set up a few of these pairs for a stereoviewer and make prints to see if I can subject the public to looking at these.

Sunday, January 26, 2020

Building a 45mm 6x6 stereo Populist

One of the things I enjoy about the Populist design is that it’s fairly easy to modify to different formats. I’ve extended it to longer distance to the pinhole, used wider formats, and made stereo cameras. Since I did the redesign last year, I hadn’t made a stereo version from the new template.

The 6x6cm format is particularly appropriate to stereo. Side by side chambers make the baseline between pinholes almost exactly the distance between human eyes. Most manufactured 35mm amateur stereo cameras like Kodak’s Realist had this separation, but made pairs on every third frame.

Poking around on the internet it looks to me like the most common angle of view (aka focal length for the refraction enthusiasts) for stereo cameras is the “normal” one of about 40 degrees which supposedly reproduces the perception of depth of human vision. In experiments I’ve done, angle of view is less important than the distance to the subject and the baseline. There have been couple pinhole cameras available for sale and, as is pretty common in pinhole, the angle of view is typically a little wider. I’ve done quite a bit of 6x6 pinhole at 60mm, so I decided I would see how it worked out at 45mm, about a 67 degree angle of view, which is very wide for stereo, but actually a little long in the pinhole world unless you make a camera yourself.

In order to make a Stereo Populist, take two templates for the camera length you want, and cut off the end for the film chambers on opposite sides.

Then glue them together on to the cardstock to make the camera body. This will eventually have to be done for the back as well.  Here's the two parts of the back template glued together.

Glue the two internal assemblies together.

Otherwise it’s just like making a regular Populist.  It does require two shutters.  I have used two separate shutters and connected them with a bar in previous stereo cameras. Since I was thinking of taking pictures of buildings, I wanted a rising pinhole, so I modified the shutter I made for the stereo fronts for the 6x9 Variable Cuboid for this camera’s longer baseline.

Since the divider between the two chambers is now in the middle, I decided to put the tripod mount external to the box in couple layers of foam core glued to the bottom. The counter shutter can remain in the same place and either one can be used, but you have to remember to advance two frames for every picture.

I did encounter a few problems and they may be related.

I painted the inside of the box and sides of the boxes where they slide together with some black satin finish interior latex paint. That may seem like a smooth surface, but when two of them are in contact, they don’t slide well at all.  I think it also may have absorbed in to the card and made things swell a little.  After the paint dryed, when I put the two boxes back together, it was almost impossible to get them apart. I eventually sanded off the paint on those surfaces.

If the take up reel isn’t parallel to the supply reel, eventually it will skew in one direction and completely jam up the film advance. I’m not sure if I hadn’t gotten it glued right or if the latex paint distorted it, but the take-up chamber was a little wider on the bottom. The film locked up before I even got to the first frame. I made a little spacer and taped it to the bottom of the divider and that did the trick. The film advanced very smoothly thereafter.

 I loaded and unloaded this roll of film three times and in addition to crumpled backing paper at the beginning, let’s just say it didn’t do it any good.

These are set up for Crosseyed viewing. It’s easy to learn with this simple exercise.

I also broke down and bought Anaglyph Workshop in case you have red/cyan glasses. I hope I got the alignment correct. Unlike crosseyed viewing where your brain and focus muscles do all the work, anaglyph does need alignment. It’s a hand made camera. OK? Every .16mm error from on-axis pinhole placement equals a degree on the image. The pinhole itself is only .3mm. The best thing I found is to adjust it until the image looks most monochrome. Viewed with your red/cyan glasses on, out of alignment they have an overall reddish or cyanish cast, like something you might correct with color balance. It gets sharper when it’s aligned too.

I thought the hydrangea would be a good subject.  I always forget how wide angle 45mm is on 6x6cm format and kept finding myself having to move closer to things to fill the frame. The nearest branches are about 4 feet (1.3m) and the garage is about 12 ft. (3m). Looking at the left side of the garage, I can see a definite separation from the distant trees.

Out in the street the near tree is maybe 30 ft. (10m) away and the much taller trees across the road are twice that. I can see the separation, but it’s not really dramatic. Stereo imaging is based on parallax, and a 166:1 (10m/6cm) triangle doesn’t look that much different than a 330:1 triangle. Everybody knows that wide angle cameras make things look farther away so you have to consider that in what your brain is trying to figure out.

The “Then and Now” exhibit at the Public Museum was part of the reason I’m doing this. A lot of pictures in the museum archive are stereoviews and the curator told me they had put stereoviewers and cards out in a previous exhibit and the public really liked looking at them.

One was of the Oshkosh Normal School which burned in 1896 and was replaced by Dempsey Hall. I expected to take this from the sidewalk but I had to trudge through the snow halfway to the building in order to get it to fill my frame. Stereo imaging is as much art as it is science. One of the tricks is to put something in the foreground so you get a real 3D wow effect.  I thought the trees would take this function. It’s a better trick if your foreground object overlaps your background object. If you look at the top of the entrance where it’s right next to the tree branches you sort of get that 3D wow effect. The pine trees are even closer to the camera, but since they don’t also overlap the building, you hardly notice.

The Dale School was our first home in Oshkosh. Again, I thought the trees and the low wall would give that dramatic depth, but again I was too far away. This was as close as I could get and keep the camera level and have the top of the building in the frame even with the rising front. Shoulda just gotten closer, pointed the camera up and lived with the converging verticals.

Probably the best of the lot, incorporating all these tricks are the chain link backstops in East Hall Field. Unfortunately, there’s no stereoview match for it in the museum archive.

For this camera and for those similarly wide angle pinhole cameras on the internet, I’ll paraphrase Robert Capa: “If your stereo effect isn’t good enough, you’re not close enough.”

Tuesday, January 14, 2020

From f295: Lens Replacement

F295 was an international discussion forum begun and administered by Tom Persinger. Originally just about pinhole photography, it expanded into all kinds of alternative methods.  It was active from 2004 until 2015 but it remains on-line. Recently it disappeared from the web for a few days, and that prompted me to decide to reprise some of my favorites here at Pinholica, for backup if no other reason.

Andrew Bertram posted a picture of him giving blood on Facebook recently and wondered if anyone else had done any medical pinholes. I posted this on f295 on October 1, 2007.

For a few seconds last Friday, my right eye was lensless, but they did replace it with another lens. Here I am waiting in my gown, then all prepped for surgery and ready to go, and then waiting outside in the free fashionable sunglasses. Didn't have the courage to ask if I could bring the camera into surgery.

The Populist, .15mm pinhole 24mm from 24 x 36mm frame on ISO 200 film. Three minutes, two minutes, 4 seconds. 

Thursday, January 9, 2020

Adventures and misadventures with the Variable Cuboid.

For the Oshkosh Public Museum’s “Then and Now” exhibit, I really wanted to make a match for one of the archive pictures of a woman working at the Buckstaff Furniture factory. The site is now occupied by the Menomonie Nations Arena which hosts the Winter Farmers’ Market.

These apple sellers had a colorful display. I hadn’t noticed the distracting poster of the guy with the sword and the pizza behind them, and the round table cloth doesn’t do much for the composition.

I buy cheese from this lady nearly every week. All the boxes, blocks of cheese and tubs of spread make a better match for the belts and pulleys in the archival picture

These two were with the 45mm front for the Variable Cuboid.

When I made the new camera for the Building the Variable Cuboid post, I made a 100mm Front, which I hadn’t used yet. Better try it out.

In order to get any shadow detail when photographing holiday decorations, the lights often get really blown out. I exposed this for the time measured without the lights and turned them on for just the last minute.

I put a continuously adjustable rising front on the 100mm and tried it out on the just-a-bit-higher-than-my-tripod-will-go pothos above the bathtub. This is with the front at maximum rise. One nice thing about the long distance to the pinhole is there’s virtually no vignetting even this far off axis. The verticals did remain parallel.

While I was waiting for that exposure, this blue bottle with the shiny gold lettering on the dresser in the bedroom across the hall caught my eye, and I am a fan of close-ups. This is about a 1.5 to 1 macrophotograph.

I finally got around to going out with the 100mm while shopping for holiday gifts. While in the store where I’ve been buying jewelry for Sarah for years, I thought the room dividers and the counters formed an interesting composition. No one else was in the store so while they wrapped my package, I opened up the tripod and made this exposure.

And then, disaster!

I’ve been using the Variable Cuboid for almost a year now in all sorts of conditions. I’ve only seen one light leak when I rode around for about 50 miles on a couple bright sunny days with the camera on the tripod strapped to the rack on the back of my bicycle. Since that also included one time the camera jostled off the tripod and bounced down the highway, it didn’t seem like a problem. Now that I think about it, since then I’ve been careful to take the camera off the tripod and put it in my back pack while riding around. This time, however, I just carried it mounted on the tripod while I walked around downtown in the sunshine looking for something to photograph. This was also with the Lomo 800 in the camera, so it didn’t take as much stray light to cause mischief.  It appears that the sun can get down the light trap if given an opportunity, at least with this front.

The solution is more cardboard, of course.

On the top of the camera the front slides under the winders which keeps it in pretty good contact. The bottom is held tight by the tripod mount. On the sides where the pictures indicated it was vulnerable, I glued one double layer of cardboard on the film back just where the fronts stop, and then another which the front will slide under and deny Old Sol a chance to sneak down that way. It makes it a little bit fussier to change the fronts, but it’s still doable.

I hope it works.

Wednesday, January 1, 2020

From f295: On the fourth day he rested,

F295 was an international discussion forum begun and administered by Tom Persinger. Originally just about pinhole photography, it expanded into all kinds of alternative methods.  It was active from 2004 until 2015 but it remains on-line. Recently it disappeared from the web for a few days, and that prompted me to decide to reprise some of my favorites here at Pinholica, for backup if no other reason.

During the break between Christmas and New Year’s in 2007, I made five Populists to give as premiums for a contribution to support f295. I finished them and posted about it on New Years Eve. Every year on f295, there was a special forum for pictures done on New Year’s Day, kind of a members only version of Pinhole Day. I posted this under the title “On the fourth day he rested” on January 3rd, 2008

I have to say I had an enjoyable time working on getting a picture for the New Year's Day gallery. No braving the cold for me. I spent most of the day watching movies on TV and reading.

I really didn't even have to get up if I didn't want to.

Here are Sarah and I lounging in bed about 10:30. Cats coming and going thoughout the exposure.

The Stereo Populist. Set up for crossed eyes. About 10 minutes exposure

This is where the TV watching and reading took place. The chair which is enjoying the comfy environment with me is just to the left of the camera here.

The prints on the wall are from my earlier period in the late '70's-early '80's using an alternative optical scheme.

The Populist. about 10 minutes. 

Maybe this will make it more real for you.

The Stereo Populist, about 10 minutes, set up for crossed eye viewing. 

Here's a shot of the plants you can see both in the above photos and the New's Years Gallery photo during the brief period when the sun rose over the house next door and shone on the sun room windows.

The Populist, about three minutes exposure. 

I did have to compete with Spenser for this spot on the couch for a while, but he's as crazy as a Minnesota pinholer and kept going out on the back porch and coming back in all day.

The Populist. about 10 minutes.

Stewart is a much more sensible kitty and slept on a chair in the living room most of the day.

The Stereo Populist. Set up for crossed eye viewing. about ten minutes exposure. (He was really fast asleep, but he spends most afternoons that way.)

Even the ceramic kitties from the Metallica tableau in the kitchen were provided with a little extra comfort.

The Populist, about 10 minutes exposure.

And of course one has to eat.

The Populist, exposure as long as we spent having lunch.

I have been taking guitar lessons for past six months (and I'm only on page thirty-eight), so I did have to venture down stairs in the cold to practice.

The Populist. Exposed while playing scales and exercises and working on "Waltz in F"

All in all a pretty good day.

And in case you were wondering, here’s the photograph I submitted to the New Year’s Gallery.