There are many posts online singing the praises of 8mm telecine by scanning individual frames with a macro lens or scanner. And rightfully so – in the average case it produces better results than the alternative of realtime recording of a video projected on to a wall, projected within a film transfer box, or ‘directly’ using a special lens configuration.
With these assumptions, along with a first attempt filmed off a wall that looked mediocre at best, I went on a wild goose chase trying to build a hardware solution to what I perceived to be the greatest issues with filming off a wall: focus, frame blending and the rolling shutter effect. The focus seemed consistently worse than it could have been due to multiple variables at play: projector lens zoom, projector lens focus, camera focus, camera position, original film not always perfectly focused. To capture a flicker-free image, I found the framerate and shutter of the camera had to be configured to span potentially multiple frames of the original, which introduced a nasty blending effect. Motion appeared nice and smooth, but panning lost all detail, and ghost images occurred across transitions. Panning exhibited rolling shutter / ‘jello’ effect, vaguely similar to the tearing that results from lack of vsync, where the top half of the image would be a frame different from the bottom half.
I tried using a Sankyo variable speed projector, but it had failed to stand the test of time and had multiple issues (microswitch failures, film gate misaligned/broken). I tried focusing using a reversed lens macro configuration in conjunction with the projector lens pulled out further than usual – this resulted in a full frame in reasonable focus, but with bad chromatic aberration everywhere but the centre. Perhaps this would have worked with a macro setup with a longer working distance (max I could achieve was about 0.5cm too short), eliminating the need for the projector lens, which may have been the source of the CA. Finally, I investigated a hardware solution to run the projector off a controllable motor to advance frame by frame, but decided to save that as a last resort due to the level of hassle involved.
Eventually I came to the solution of using software to tidy up the ‘recording the wall’ approach to the same level of quality that I have seen from professional telecine with a proper machine.
- Canon DSLR supporting Magic Lantern and video DPAF (I used a 70D)
- Fast normal lens with minimal distortion (I used a Sigma 30mm Art f1.4 stepped down to f2.0)
- Projector with half or variable speed control (I used a Eumig with 9fps and 18fps options)
- A4 paper stuck on wall
I consider this a ‘software approach’ due to the lack of hardware mods or unusual hardware configurations. The only hardware involved is the bare minimum of a camera and projector.
The process is as follows:(more…)