I've done some tests, and with the Raspberry Pi lens unscrewed all the way, you can get a nice macro shot of the film, but I can only focus about 25mm away from the lens. Not bad, but results in only capturing about a 1/4 of the actual total picture size. Not good enough for the quality I want.
I have decided to play around with the optics, and have ordered a 0.67 macro lens: [ http://www.ebay.co.uk/itm/310967616338 ]
The idea would be to use the Raspberry Pi camera standard focus setup, and attach the lens in reverse.
I am hoping this will achieve the result I am looking for.
Will see in 10 days time...
-- UPDATE --
11th July 2014
I've received the lens, and it has two parts. A macro lens, and a 0.67x lens.
I unscrewed the 0.67lens and put it in front of the RaspberryPi camera.
I had to unscrew the Raspberry Pi camera lens pretty much all the way, and with the added macro lens in front of it, it resulted in a very usable image.
The usable image result in about a 1450 x 1050 image. Fairly decent for a 720p version film :)
Now to get busy constructing a feeder and fine focus adjustment system.
