Finally Some Success with the Cadobo Cam

Continued experiments with the homemade lumen camera



4/8/20233 min read

I think this has been case of job interfering with life. I've been surprisingly busy with school lately, this combined with the persistently unpleasant weather here has really bit into my time to work on the new camera in its various prototypes.

While my initial experiments with the new 63mm f/2 lumen camera were promising, I wasn't getting anywhere near the colors I'd achieved in the past with Jorge Otero's wonderful Lumenbox camera. Part of this may amount to comparing eggs to apples as my camera uses a much different lens than the Lumenbox. The Cadobo cam uses an 45mm dia. plastic Plano-Convex lens with a focal length of 63mm, while the Lumenbox uses a plastic asymmetrical Bi-Convex 25mm lens with a 50mm focal length.

Regardless of whether I was using my old standby paper, Aristsa Edu grade 3, or the new paper I've been trying Fomapan MG Classic 320, my colors were mostly quite muted with the Cadobo cam, at least compared to the Lumenbox. I attributed this to a couple possible causes; It seemed like the Cadobo cam boxes were too vapor tight, allowing the moisture from the dampened photo paper to fog the lens, thus reducing contrast and possibly reducing the range of colors? I also wondered if the lenses I was using had less chromatic aberration than the Lumenbox, again possibly reducing the range of colors?

I began to line the Cadobo cams with the stick on velvet that I use for light seals and instead of soaking the photo paper in water, I just misted it with water. This seemed to have little effect.

Below are a couple shots from yesterday. The first (on the left) is a 10 hour exposure on a partially sunny day with Lumenbox (f/4) and fully dampened Arista paper, a control shot of sorts.

The middle shot, also from yesterday is a 10 hour exposure with the Cadobo cam (fitted with f/4 aperture) using undampened Foma paper.

The shot on the far right is from today, a cloudy day, it's a one hour Cadobo cam shot with lightly misted Foma paper and an f/2 aperture. The camera was wearing a plastic sandwich bag to protect it from the intermittent showers. I do like this image, muted colors and all and plan to use the Cadobo cam in this configuration in the future, sans sandwich bag I hope.

So again, these tests aren't very scientific at all, mostly just illustrating the differences between the two different cameras an lenses.

This last shot, again from today is a 5 hour Cadobo cam (f/2 aperture) exposure with lightly misted Arista paper, also with the camera wearing a protective sandwich bag.

As soon as I pulled the paper from the camera I knew I had some good colors! In my mind they're up there with Lumenbox colors. It's good to know that the new lenses aren't the problem. It seems to be mostly a matter of exposure and aperture. I think at this point I'll use the f/4 aperture with the Foma MG Classic paper for slightly higher resolution more subdued color images and the native f/2 aperture of the Cadobo cam with the Arista paper for the wilder, more intense colors that I usually prefer.

While I was exposing this shot I built a control camera of sorts, it's a Cadobo cam as I've been building them but with an actual Lumenbox lens, hopefully this will allow me to trouble shoot a little better if I'm not getting the results with the Cadobo cam that I'm hoping for.

I hope to post comparative photos of the original (well version 2 actually) Cadobo cam and the hybrid Cadobo/Lumenbox soon.

I've also built a gigantic (well, larger anyway) Cadobo cam that uses a 100mm diameter 150mm focal length glass Plano-Convex headlight lens. I also hope to have results from that soon, this new Cadobo XL uses 4.25" square paper sheets.