Sunday, June 25, 2017

Overexposing Tri-X in the Oshkosh Populist

Over the last two decades, I somehow have gathered six rolls of 35mm Tri-X.  The only time I've ever done any pinhole with 35mm in black and white was last year when I finished a roll that otherwise had been used in a camera with a lens.

My student period from earlier this year made me a little curious again, and I decided that the Oshkosh Populist with it's panoramic format would be a good tool to use this film with.

I'm used to guessing exposures with ISO 200 film in an f160 camera (The Populist) so I thought f144 at ISO 400 wouldn't be too different.  Turns out you can't get away with overexposure with silver the way you can with color dyes, and I ended up with a lot of blocked up highlights, and even a few shadows that were a little hard to push some light through.

But, lets see if we can get anything out of these negatives.  I only got three I liked.

As the name implies, the Oshkosh Populist is all about working with the level topography of Oshkosh.

The Buckstaff Plant on South Main St. has been an eyesore and fire hazard since it closed in 2011.  A good bit of the rest of this area can best be described as blighted, although a few somewhat industrial businesses still operate. This year, the Milwaukee Bucks decided to locate a minor league  team in Oshkosh - the Wisconsin Herd (of deer, get it?). The Buckstaff plant was finally torn down, and the new arena is under construction, and hopes are high that it will bring a major renewal to the area (a micro-brewery is already starting across the street).

Just across the railroad tracks on Lake Winnebago, on a island all it's own is the Pioneer Inn. It used to be one of the hot spots for business and vacation travel in Oshkosh. It closed in 2005 when the owners got into a dispute with the Department of Natural Resources over a reconstruction project of the hotel, and it's been vacant ever since.  I wonder if the new arena will be sufficient impetus to get it going again?

On the north side, hemmed in against Highway 41 and suburban housing developments is the Oshkosh Correctional Center, a 300 prisoner medium security prison for men. Except for the entrance, it's surrounded by a giant berm and all you can see are the lights and guard towers. I couldn't tell if there was anyone looking down at me while I was taking this picture.

I'm going to continue to see what I can do with the Oshkosh Populist with this stash of sort of out-dated Tri-X.  I replaced the .27mm pinhole with the .2mm I measured with the Teslong USB microscope, which gets me about a stop slower.  It's theoretically too small for the 35mm distance to the film, but I've had success with smaller than ideal pinholes in other cameras, and I think diffraction is more likely to lower contrast a bit than sharpness, which I could kind of use with these negatives.  I've also learned my lesson and am stopping to actually measure the exposure, and I've been practicing trying to make one second exposures.

Friday, June 16, 2017

Measuring pinholes with the Teslong USB microscope.

June 2019. When my university retiree account disappeared with a new change in policy, the pictures I uploaded to this blog while logged into that account disappeared. I'm working on fixing that but it's going to be at least a summer long project. 

If you follow me on Facebook, you may recall that I posted about a new favorite toy, the Teslong USB microscope. It's about the size of a pencil with a camera at the end that's held on a nicely adjustable stand.  There's a focuser on the other end so you can adjust it to various distances, and it has LED lights on the camera end to illuminate the subject. It's marketed as a microscope with up to 200 times magnification. (Just so you're not wondering about it, that's a .2mm pinhole at the right of the screen.)

In the comments to that Facebook post, Earl Johnson asked if you could measure pinholes with it. Well, since the magnification is a function of it's distance from the subject, which the device can't report to the computer, you can't tell directly what the size of anything is.

I usually measure pinholes with a scanner. Since the scanner knows exactly where the pinhole is and is scanning at a precisely known resolution, you can just read the actual size right off the screen.  The highest I can scan is 4800 dpi, which makes this .3mm pinhole about 60 pixels across. A bit of a problem is that the scanner software doesn't deal well with bright highlights and the pinhole is made from brass, so it tries to fix that and makes a way too high contrast image and it's often difficult to see just where the edge of the hole is. This example is better than most. Anyway, it works but it could be better.

I just happen to need a .2mm and a .15mm pinhole this week, so I got my brass, needles and emery paper out and tried to see what they looked like on the Teslong and see if I could measure them.

First I had to standardize some things. I wanted as much magnification as I could get, so the first thing I did was see how close I could get to something and still get it in focus. When you turn the focusing knob, you can feel stops at either end. So I put it at what I thought was its near point (lenses, ya know - by the way I just learned that term from Wikipedia) and then slowly pulled it away from the table until it was in focus.  That turns out to be about a quarter inch. It's pretty easy to get it set up to it's minimum focus repeatably.

200x magnification means movement gets magnified 200x too, so pointing is a little tricky. That swirly mark that's on the screen in the picture above was made when my drilling needle, which I was using to hold down the brass against the table, swept across the screen. Pretty exciting. By carefully moving it by nudging the base around you can get enough control moving it to find what you're looking for. The field is much less than that illuminated area, but it's possible to find the approximate center of the spot of light. You don't need the pinhole to be in the center, you just need it on the screen.

The camera uses the shareware video capture program VLC to display the image in a 1280x720 pixel window. VLC wants to capture video, so the easiest way to get a still image is to do a screen capture.

What I need now is a known object to compare my pinholes to.

I happen to have several sizes of Gilder EMS pinholes. They come in vials of 100, but Earl Johnson, I think, still resells small quantities for about $1 USD apiece.  I'll let him give you contact info in the comments if he wants to. Anyway, my stash includes some .2mm apertures - just what I'm trying to measure.

They look pretty good under magnification.

Selecting just the pinhole, it measures 100 pixels across (how convenient), so now I can measure with it and it's a little better than twice as sharp as the scanner  (recall that my scanner had 60 pixels for a .3mm hole).

I happened to have a pinhole that I recently measured with the scanner as .2mm, so I put that under the scope. I took the new image and pasted it next to the image of the Gilder aperture. I guess my measure with the scanner was pretty accurate. They're exactly the same size.  But, what you can see now is that around the edge of my homemade pinhole is a bit of fuzziness, probably dust from sanding off the burr on the exit side of the needle hole.

I bet some canned compressed air would get rid of it, but I don't have any of that. Blowing with my lips didn't do anything. So I stuck the needle tip in as gently as I could and spun it a little. That pretty much did the trick cleaning out the schmutz without enlarging the pinhole. Not bad. I think I'll use this one.

Now I've got to try to drill a .15mm.

I used my standard method for .15mm pinholes, drilling right against a hard table top, this time with the needle held in the eraser of a pencil.  Much to my surprise, it measured 75 pixels - exactly .15mm - and very clean with no fuzz. Two for two. I guess I'm starting to get the hang of this.

Both pinholes are now mounted on cameras so we'll see how they do when I get some film through them.

The Teslong seems like a pretty good deal for $41.

Friday, June 9, 2017

Two orphaned 120 rolls of Portra 160.

I've just finished two rolls that started one way last year and then kind of got forgotten.

When I finished the roll which I took to the Paine Art Center in the Evil Cube, I thought I had left the camera sitting empty on display on a tripod in the living room, but when I went to load it for documenting my surgery experience, I pulled the back off, saw that I had reloaded it with Portra 160 and as fast as I could, pushed the back closed again.  Wanted to use the 400 for the medical coverage, so I just rolled the 160 back on the original reel (why you have two winders) and put it in the freezer with a note on it. After I finished the Shut-in challenge with the faster film, I loaded the orphaned 160 back into the Evil Cube.  It was on frame one when I opened the camera, so I thought I would be safe to advance to frame four. Turns out, frame three was probably OK.

This was when the magnolia was still blossoming, and I'm always taken by the pattern of the falling petals around the trunk and the daffodils.

By this time in my recovery, I was cooking a little again, so got seduced by a sunbeam in the south kitchen window. Since I've taken similar shots many times, I hung the cane on the sink to place it in context.

This was a week before WPPD, and I did a more loosely framed version of the same dish of fruit that was tightly cropped on Pinhole Day.  It's actually sitting on cake plate (you can see the shadow of the base), but it looks a little like it's floating in air.

The other orphan roll, was from the other camera I had with me that one gloomy day I shot in the Paine Art Center, the Glenlivet Vertical Populist.

It was very dark except for a few minutes of sunshine that day, and I could only fit one hour and a half exposure in with that camera. This is in the powder room off Mrs. Paine's sitting room. It's behind a velvet rope across the door which is just to the left of the frame, so you never see it face on like this.

When I got home, I put the camera on the shelf in the basement and kind of forgot about until I shot the other orphaned roll.

In order to ride for the first time after surgery, I had to put the summer tires on, which I did on the sunny driveway.

One of the oaks making a calligraphic stroke on the garage.

Gene and Laura came to visit. Here's Gene shortly after they arrived after driving through rain for three hours.

He had calmed down quite a bit the next morning.

Laura in a near real time discussion of a casting announcement for a community theater production.

Don't you just hate having to use up the leftovers after you have guests?

And, in case you were wondering about what happened to that tulip trying to grow up through the rose thorns on Pinhole Day.

The first three with the Evil Cube.  .3mm pinhole 60mm from 6x6cm frame.

The rest with the Glenlivet Vertical Populist. .3mm pinhole 45mm from 6x6 frame.