Using a filmstrip projector for DIY telecine?

Ben Syverson · February 14, 2010

Hi all, I'm new here... I just bought old 35mm filmstrip projector (look up "Dukane Micromatic") hoping to use it as the transport mechanism for a DIY 35mm telecine/scanner. They're less than 1/10th the price of a 35mm stop motion setup...

Does anyone have any experience with these beasts? My theory is that I could either project the image directly onto a DSLR sensor, or use a macro lens to photograph the film in the "gate." The original lamp would be removed and replaced with an RGB programmable light source (an iPhone running Catchlight). An intervalometer would simultaneously trigger the Micromatic to advance 1 frame and trip the camera (set to 2 second self timer).

My two biggest concerns are focus and framing. I'm worried the film might move around slightly in the gate and/or slip out of alignment with the frame... If so, that might kill this project pretty quickly. But if it's consistent, it seems like it could be a good platform...

Thoughts?

Ben Syverson · February 26, 2010

So I got the projector... Focus variability won't be a problem, as the film is held sandwiched between two plates of ANR glass. Registration doesn't seem to be a problem either -- the film advance mechanism is simple, well-built and accurate.

The biggest problem will be getting the light source placed correctly... It may involve some Dremeling. The ANR glass means the light has to be 100% even and soft, or you'd see the texture.

Shooting with a 1:1 macro lens on a full frame DSLR, I'm able to image 100% of the film, including the perfs and keycode, which should help with registration.

The actual image area winds up being about 3.5K, but so far I'm happy with the detail I'm resolving. I'll post some examples soon...

Paul Bruening · February 26, 2010

You only have to have edge numbers from a telecined pass (workprint) to choose with physical verifiability the useful frames in the scan pass (mark an X at the head, make sure it shows in the telecine, line it up on the X in the gate for your scan pass and your Tcine data will match your scan pass frame counts). As long as you have a way to manage frame counts with a computer so to scan only useful frames you're in good. You can make up shot lists by hand on the computer. A keycoded system might be useful to read general frame locations but you still have to decide on and tell the computer which scan shots you do and don't need with the knowledge that it can get them with frame accuracy. I guess a keycode reader could get part of the info that you need but some kind of perf counting or some kind of revolution reading of the motor still has to be done since keycodes are spaced. At that rate, you might as well let the revolution counting or perf counter manage the whole roll. You have to make workprint decisions first, anyway. That is your best source for scan shot lists. I'm guessing that you won't want to make all 1,730,000 frames of a 2 hour feature at 10:1 shooting ratio into high res scans to cover both workprint and conforming steps. 173,000 4K RAW scans alone take up about 5.5TB of drive space. 10X that gets noticeably hard to manage.

Does that make sense? Is it useful or am I goofing up a different approach you already have in mind to solve those issues?

Paul Bruening · February 26, 2010

To alter my post, you don't really need any edge info assuming your frame counting method on the film is utterly reliable during scanning. An X at the head and tail of the roll included at sync speed with the telecine capture gives you all the verifiable info that you just have to have. Adobe can change from any normal frame counting system to sequential frame counting (making sure the capture is non-drop frame, of course). As long as the math in the editor matches frame for frame the edge number math between X's, you can depend on the editor's Tcine, sequential numbering for dependable scan lists. I just liked the idea of seeing the edge numbers included in the telecine and have the confidence I could physically verify the scan list accuracy in the off chance I get hick-ups in the telecine capturing or editor. Video, software and computer circuits do hick-up from time to time.

Ben Syverson · February 26, 2010

Paul, thanks for your notes! That does make sense. I'm looking at the keycode/edge numbers as a bonus -- the main thing I was interested in capturing was the perfs, so I could use them for stabilization. But now that you have me thinking about them more, they could potentially be pretty useful... The edge numbers could serve as a "sanity check" during the stabilization process, to make sure I'm not skipping frames.

If it seems like I'm skipping a lot of frames, I might have to read the keycode in realtime (not a problem since my system will be so slow) and have the computer control the forward/advance mechanism. (Right now it's a "dumb" intervalometer)

In terms of workflow, it may make sense to use the HD video mode and the "fast" advance on the projector (2-3 fps) to read a roll in quickly into a compact format. That can be used for the edit, and then the edge information used to create an "EDL" for the final scan.

Storage-wise, I'm sort of trying to plug my ears and say "lalala." :) All of my early tests will be 100' rolls, which works out to ~40 GB. I'll be getting a cheapo TB drive or two for those tests, and after that who knows... I'm not even 100% sure this will be a workable system. I know that right now the filmstrip projector is a little too rough (okay, way too rough) with the film. I'm seeing scratches, mostly in the perf area, and need to eliminate those before I run any negatives of consequence through.

Paul Bruening · February 26, 2010

Paul, thanks for your notes! That does make sense. I'm looking at the keycode/edge numbers as a bonus -- the main thing I was interested in capturing was the perfs, so I could use them for stabilization. But now that you have me thinking about them more, they could potentially be pretty useful... The edge numbers could serve as a "sanity check" during the stabilization process, to make sure I'm not skipping frames.

If it seems like I'm skipping a lot of frames, I might have to read the keycode in realtime (not a problem since my system will be so slow) and have the computer control the forward/advance mechanism. (Right now it's a "dumb" intervalometer)

In terms of workflow, it may make sense to use the HD video mode and the "fast" advance on the projector (2-3 fps) to read a roll in quickly into a compact format. That can be used for the edit, and then the edge information used to create an "EDL" for the final scan.

Storage-wise, I'm sort of trying to plug my ears and say "lalala." :) All of my early tests will be 100' rolls, which works out to ~40 GB. I'll be getting a cheapo TB drive or two for those tests, and after that who knows... I'm not even 100% sure this will be a workable system. I know that right now the filmstrip projector is a little too rough (okay, way too rough) with the film. I'm seeing scratches, mostly in the perf area, and need to eliminate those before I run any negatives of consequence through.

Mitchells are cheap these days. They have all the head features you need. From my assessments to date, you will still have to do some monkeying with the gate and/or pressure plate. The easiest way is a pressure plate chopped out in an upside-down U shape that will allow enough light through on a 4-perf frame. You'll then put a 45 degree bounce board behind that (clearing the registration pin assembly is the hassle on that).

On the storage note, as you know already, 2TB SATA 3.0 drives are going for as low as $150.00 these days. The storage issue gets better with each passing quarter.

Paul Bruening · February 26, 2010

If it seems like I'm skipping a lot of frames, I might have to read the keycode in realtime (not a problem since my system will be so slow) and have the computer control the forward/advance mechanism. (Right now it's a "dumb" intervalometer)

I recall going over this with Bruce: What happens if the keycode stops on the reader, in between scans? Can it still make the read? Revolution or perf counting would bypaas this problem as well as the keycode spacing problem. I dumped the whole keycode approach since Bruce and Paul had an accurate and cheaper way to handle the whole system through 1:1 motor rotations, which the Mitchell does already.

Ben Syverson · February 27, 2010

Yeah, the keycode stuff would be experimental... I'm thinking I'll play around with it post-scan, but not worry too much about it as a control mechanism. I'm getting excited to get this thing running! I'll upload some test scans soon...