Heavy Metal

Filing out the negative holder of a Pentax slide copier.

After toasting a few films with the “Canon P” rangefinder I got in Japan earlier this year I ran into problems when trying to scan the negatives: The film gate of the Canon is just ever so slightly larger than those of the Pentaxes I usually use, resulting in a ever so slightly larger area of film exposed to light. This made it impossible to leave a border of unexposed film around the picture in the digital file, which I have grown used to.

The solution is to file out the negative holder of the slide copier I use to digitize my 35mm films. This leaves just enough room around the negatives made with the Canon to form a black border. The negatives from the Pentaxes are not affected by this.

Below an example taken with the Canon P, now with proper black border of unexposed film.

Hamburg, May 2017. A hammock over the water of the Alster.

Slow progress

Second iteration of the slide copier setup, now with enlarger lens and section of drainpipe.
Second iteration of the slide copier setup, now with enlarger lens and section of drainpipe.

The light in Hamburg is still not nearly bright enough for doing photography. This hardly matters, since I don’t have time to roam around outside anyway. What I did have time for was to improve the slide copier setup I’m using to digitize my negatives.

While at my parents home during the Christmas holidays, I rediscovered an old enlarger lens (Schneider-Kreuznach Componon 1:5,6/80) that I had bought a few years ago attached to an enlarger. Turns out it has just the right focal length to work with the camera in this setup. Having determined this, it was just a minor hassle to attach the lens to a M25 to M42 adaptor and that one to a M42 to Pentax-K adaptor which allowed me to connect it to this bellows unit. The distance between the lens and the slide-attachement was still too long to cover with the included bellows, so I had to cut a section of drainpipe to the right length, to act as a shade keeping stray light out. It looks a bit rustic, but it gets the job done. To avoid reflections on the inside of the pipe I used matte-black spraypaint.

Even though the Componon lens is already in quite bad shape (no way around that, new ones are prohibitively expensive), the optical quality still easily beats the zoom lens I was using before.

Progressive progress – digitizing film using a slide copier

In the Sachsenwald near Hamburg.
The Sachsenwald near Hamburg. Digitized using the new process.

In the last few days and weeks I have been too busy to get much real photography done, but I was able to at least improve the speed of my workflow, using a slide copier attached to a digital slr.

The problem

Until now, it took me a long time to get the photos I made into a presentable form. One of the reasons for this was my trusty “Epson Perfection V370 Photo” flatbed scanner. While I cannot fault the quality of its output, it takes about three minutes to scan a negative, which for the usual film strip of 36 negatives quickly adds up to serious time. Furthermore, this is not even counting the time needed to clean up the resulting files (removing dust spots from the pictures, adjusting the grey values, etc.).

The solution?

I decided to try a different approach, using a digital slr to photograph my negatives and thus reduce the time to get digital files. For this, I now use a slide copier, a machine originally used to make copies of slide film (or negatives) with a normal camera. It basically just consists of rails to keep the film to be copied at a precise distance from the camera and provisions to adjust this distance as needed. The one I got was manufactured by Pentax as an accessory for their cameras sometime in the 1980s. Thanks to Pentax still utilising the same lens mount (the infamous K-mount) on today’s digital cameras, it is no problem to seamlessly connect it to a modern camera for producing digital copies of the negatives.

Pentax macro bellows with slide copier attached to a Pentax K-x.
Pentax macro bellows with slide copier attached to a (digital) Pentax K-x.

The process

This is how I do it: The slide copier is connected to a tripod and the camera is attached to its back. The adjustments needed to set the right distance between the negative, lens and camera are done in advance, based on measurements I took before with a test negative. Then the whole apparatus is aimed at a white curtain in direct sunlight, to provide a uniform, strong lightsource to illuminate the negative. After the right exposure setting for the negative has been set on the camera (the histogram displayed by the camera is extremely helpful for this), a full film can be quickly “scanned” with little need for further adjustments. (Perhaps a slightly dense or thin negative might require some exposure compensation, again, I keep an eye on the histogram provided by the camera.) After about a quarter of an hour, the digital files are ready to be uploaded to the computer.


The advantages to this process are manyfold. Speed is first and foremost. Using the time saved on digitizing the film for doing the digital darkroom work, I can finish the photos much faster. Secondly, the direct manual settings on the digital camera allow for much more control of the scanning process (at least compared to a consumer-level scanner).

Since this is a “lo-tech” approach, it can also be easily upgraded and used for a long time: Just connect the latest digital camera to the back and the quality of the digital files will keep up with the latest technological advancements. (Or the advancements of second-hand gear, one or two generations behind…)

Finally, while the principle of capturing light shining through the negative with a digital photo-sensor is the same as with the scanner, the files produced by the camera seem to have much more “bite”.

Disadvantages (or room for improvements)

Of course there are disadvantages to this process, too. Most obviously, the slide copier was designed to be used with film cameras, in other words, to use the “full frame” sensor format. Because the digital cameras at my disposal all use the cropped sensor format (APS-C), the scales and measurements on the slide copier change in relation to each other. This for example precludes the use of most of the excellent macro lenses designed for it. I had to make do with a SMC Pentax-M 40-80mm F2.8-4 Zoom lens, set to a focal length of somewhere around 70mm. Of course this lens is a far cry from the optical quality needed for precise reproduction, but for now, the quality is acceptable. Maybe in the (far) future I will invest in a prime lens of around 70mm focal length (perhaps an enlarger lens?), or even (gasp!) a full frame digital slr to bring all the measurements back into their normal range.

But there is no urgency. For now, I am happy with the results. Of course, when using 35mm film it also seems a bit pointless to engage in pixel peeping like this.

Addendum 31.01.2017: Later on I improved the slide copier setup somewhat, you can see it here.