Building a Super 8 Transfer Unit

[Scotness]

Bump (to get it up past the spam)

[RCBasher]

I note on your web pages you both use extension tubes and a macro, going straight onto a ccd in a machine vision camera.

I've been experimenting with my camcorder with a macro lense and can almost fill the whole frame of the camera with the Super 8 image - what would I have to do to make it fill it - just use some extension tubes? If I was stick with using this camcorder what would be the ideal way set up to get the image right?

Hi Scot, Was wondering when yoy would get to this problem ;) Don't know what the answer is, probably depends somewhat on the camcorder optics. I gave up with this approach as was getting too much chroma abberation with intermediate lenses. I actually got better results projecting onto an A4 sheet of paper and filming off of that. I eventually gave up, "bit the bullet" and bought a machine vision camera. The quality difference is so huge there is no going back...

I've also been thinking about an HD webcam instead - assuming I could take the front of it off and then use an image path similar to what you are doing now.

Been there too - I personally wouldn't bother! But if you are keen, then you need to make sure you have a camera with suitable means for extracting the frames. With the snapshot approach down a USB connection you may find you will pushing up the daisies long before you have run a few films through. Don't know if there are any faster USB3 webcams out yet at a good price?
Anyway, principle is the same - an S8 film frame size is around the same size as a 1/2" sensor (which is not actually 1/2" BTW) and will hence require around 1:1 magnification. The sensors you are likely to be looking at will probably be smaller so you will be looking at a small reduction in image size (as opposed to a huge reduction in image size normally required of a camcorder lens). I'd start with a 50mm enlarger lens with extension tubes between the lens and the camera sensor to get the magnification right and obviously move the whole assembly in and out to focus on the frame.

Good luck!
Frank

[71er]

Hi Scot!
Just yesterday I stumbled over this:
http://web.archive.org/web/200812240240 ... ction.html
Unfortunately it is not an actual web page anymore, but via web archive you can open all pages of the description on the self built telecine unit.
Seems like some of your questions can be answered!

[RCBasher]

That's the one I gave up on due to too much chroma aberation - but perhaps I had a crap condensor lens.

[Scotness]

Hi Scot, Was wondering when yoy would get to this problem

Yep I certainly got to that!! So what I'm trying now is to hack a webcam and go from there. Unfortunately I just can't afford a machine vision camera. I'll have to post some pictures but I've got a really cute little webcam I bought years ago - it's in the shape of an old movie camera - with lense, lense hood, and mouse ears - I thought I'd have to break it apart to get the lense off but to my amazement I found the lense hood comes straight off and then you can unscrew the lense and it looks just like a real zoom lense only about 2 cm long! It's just a 640x480 lense but if I can get the whole system going properly then I'll try an HD one.

Anyway I've been following Freddie's instructions fairly well - so I'm about to start experimenting with a prime and extension tubes and the raw ccd.

Alex thanks for digging that up for me - I'll save the page and read through it in detail - it looks pretty much like how Roger's workprinters were first set up with a condenser lense. I think (from memory ) the chromatic aberration occurs when the image is fairly large in the condenser lense - if you can keep the film image fairly small in the centre there should be little or no aberration -- it depends alot on the lense quality too

Thanks again
Scot

[Scotness]

Quick question too - for those in the know tell me if you think this would work:

Lets say I get all the optics right, the next thing is the capturing and the triggering - but do you think this would work:

I play the film at 3 frames per second on the projector and then just record that as straight video on the computer using a webcam.

So it's changing frames every 0.33 of a second - but if I write a script to operate on the AVI clip and get it to pull out one frame at say 0.16, 0.49 and 0.83 I should be able to get one good grab of each film frame.

Now the projector will drift a little - but I've got about +/- 0.14 of a second before I'm likely to get the frame in transition - and since I'm doing single 50 foot rolls hopefully it won't run long enough for the drift to have accumulated enough to be a problem. So this in theory should work?? I'm just thinking it would be easier than getting a trigger and capture mechanism going.

I guess the only issue might be the shutter - if I grab a frame when the shutter is blocking it?? but then does the shutter only close when the image is moving through the gate? Sorry that's probably basic knowledge but I'm still a bit of an amateur!

So if someone could clarify and give any thoughts on this whole approach that would be great

By the way the web cam I'm thinking of getting is the Logitech C920

It seems to have the manual controls I'll need - according to this review



Thanks
Scot

[RCBasher]

Hi Scot, It will also depend on what frame rate you run the webcam at. If you run at 60fps you should in theory get 10 saved frames in the avi for every film frame. No idea how in phase the projector and camera will be over the length of the film.

Had an idea, but don't know if it will work: If your webcam has audio recording too (or another mike into the recording software) then how about recording the sound of the projector? You may then be able to hook onto the distinctive pulldown beat and lock onto that to tell you which frames to grab. Just one problem though (and one reason why I recommended on my website not to go with the Eumig you have) is that it is very hard to determine what speed the frame rate is set to because nearly all the projector mechanics, including the pulldown, run at the same speed regardless of the fps setting. The only thing which changes for different speeds is an ihibit mechanism which stops the pulldown pin from always making the motion into and out of the film sprocket for slower speeds. Clever, but a pain in the arse!

I wish you more good luck!
Frank

[RCBasher]

PS: I was not thinking it through too clearly earlier Scot! Extracting good frames with Avisynth should be a doddle. The projector shutter blade will cause 3 blank periods and three exposed frame periods for each new film frame. Now assuming you run the projector at 3fps and the webcam at 60fps, you will have plenty of clean frames to get a good one from. All you have to do is use the image stats to find the first image frame after a completely blank dark frame and then use the next one (in case the first one is a partially exposed frame from the edge of the shutter blade). You will need to divide the process by three by then selecting every third frame.

You could also remove two shutter blades, only leaving the blade which hides the pull down. This will make post frame recovery very easy indeed. Will have to rebalance the shutter blade assembly though, or you may get too much vibration.

Some food for thought...
Frank

[granfer]

Scotness,
Point to bear in mind when using the bare CCD from a Webcam with extension tubes and a suitable lens... you will probably find that you will get a fuzzy image with little colour! It happened to me when I hacked one for this purpose. If you find this, the problem is that the lens you removed from the webcam has a built-in IR filter. You will need to insert an IR filter in the optical path: the problem is that large IR filters are EXPENSIVE! I solved mine by using the IR (Heat) filters from a scrap 35mm slide projector. There were two in the projector I used; one was sufficient, two even better.
I never actually got round to using the Webcam as I spotted two 3CCD C-Mount JVC CCTV cameras on Ebay... and won them (complete with power supplies) for 99p each!
Best of luck.

[RCBasher]

Will depend on the light source. If Scot uses LEDs then it will not be a problem. Otherwise, a UV/IR cut-off filter from an astro supplier costs about £16 in 1.25" dia size.

[granfer]

Agreed , Frank. As to cost, let me remind you of what you said earlier about" It is a tricky thing to give advice when it comes to someone spending money,"... it's not just the £16 (which to me is a lot of money; I'm a pensioner on limited means!), it's how all the "£16 bits" add up that you have to watch.

As to...

" Scotness wrote:I note on your web pages you both use extension tubes and a macro, going straight onto a ccd in a machine vision camera.

I've been experimenting with my camcorder with a macro lense and can almost fill the whole frame of the camera with the Super 8 image - what would I have to do to make it fill it - just use some extension tubes? If I was stick with using this camcorder what would be the ideal way set up to get the image right?"

Frank apparently doesn't know the answer, but I do. Scot, you can only use extension tubes with an interchangeable lens camera. If you want to use a "Macro Lens" in conjunction with your Camcorder the Camcorder zoom lens must have a "35mm camera equivalent" Focal Length of AT LEAST 7.5 x the Focal length of the "Macro Lens" to fill its frame with Regular 8 (slightly less with Super Eight). Contact me directly if you want a more detailed explanation, in order to save Forum Space and not to bore others that don't want to know! (Others that do are welcome as well!).

One other thing, Scot, that hasn't been pointed out yet in this thread that is not obvious... With the projector you have purchased, no matter what speed the film is running (even at 3 fps) the SHUTTER runs at 18 fps. So if you are struggling for sufficient time for the actual capture, the lower speeds won't help. It pays to remove the shutter blades completely on this machine (removing two of the three could give vibration problems).

[RCBasher]

Agreed , Frank. As to cost, let me remind you of what you said earlier about" It is a tricky thing to give advice when it comes to someone spending money,"... it's not just the £16 (which to me is a lot of money; I'm a pensioner on limited means!), it's how all the "£16 bits" add up that you have to watch.

Which is why I prefer to give absolute values rather than statements like "EXPENSIVE" because what may be expensive to some, may be a small fortune to another and peanuts to someone else. Besides, value is what it is all about after all, £16 for a working motor car would be extremely cheap! ;) A lump of IR glass out of a projector will be possibly free but must of course go between the lamp and film as it will be optically poor. A £16 IR filter should be optically good and allow for more flexibility in mounting. Scot's choice!

Frank apparently doesn't know the answer, but I do.

Good, this is what forums are for - sharing knowledge!

One other thing, Scot, that hasn't been pointed out yet in this thread that is not obvious... With the projector you have purchased, no matter what speed the film is running (even at 3 fps) the SHUTTER runs at 18 fps. So if you are struggling for sufficient time for the actual capture, the lower speeds won't help. It pays to remove the shutter blades completely on this machine (removing two of the three could give vibration problems).

I did point this out, but probably not obviously, when I said the only thing which changes with speed is the claw pin in/out movement. I would first try removing just enough of the two non-pull down blades to clear the gate and then see if it could be sufficiently rebalanced with some small weights. This will make it a lot easier in post to lock up to the frame sequence and pull out the wanted frames.

Another option would be to remove the blades altogether and then use a pulsed LED light which gets turned off during the pulldown.

[Scotness]

Thanks Granfer and Frank for the tips - I was planning on using an LCD light source - so the web cam should be alright -- I'll remove the shutter blades - and so you know my budget is AU$300 - not much but my sister is paying for this - the job is to transfer some home movie footage for her father in law - who's elderly and ill.

Scot