What would you like me to research and develop for adapters?

[Stephen Pipe]

Hi

I'm a working Director in London. But i'm fascinated with the 35 mm adapter stuff going on here. Someone has muted the idea of me lecturing one day a week at a university. They also said they'd like me to research something in my field using all other univrsity departments which would be a great opportunity for me to help the 35 adapter revolution.

Now I have some ideas, but would like some suggestions if possible. These guys are the best in the U.k at designing glass and bending light and making micro motors etc, they need practical problems to solve and I think that the indie film making scene is a great practical problem.

My brief to them would be to make it as cheap as possible and for the DIY market in terms of an adapter.

I need to know specific things that need to be developed and designed for these adapters.

Thanks in advance Stephen

[David Garvin]

Inexpensive universal flip unit with no light loss.

Okay....... go! :)

[Bob Hart]

Search on this site for posts by Brett Erskine who was responsible for some of the optical techniques now used in home-builds.

[Ben Winter]

Personally I think two years from now, the camera scene will be much different and adapters will be nonsense. Kind of late to start a revolution IMHO.

[Naoki Takayama]

Inexpensive universal flip unit with no light loss....

Maybe this is what you are looking for.
http://www.youtube.com/profile?user=bokehmon

[Naoki Takayama]

Here's a direct link.
http://www.youtube.com/watch?v=y6VD46kSpHs

[Bob Hart]

Ben has a point been talked about previously. All 35mm film emulative systems are going to be dinosur bones in about two or three years time.

The price point (new words I learnt here) of consumer level 1/3" video may come well down whilst the remaining stock of 1/3" CCD blocks is used up. The security camera and webcam industry may not want all of them, so there may yet be a future for 35mm sized groundglass devices.

One way or another all of the various researches including P+S have shaken down to a fairly narrow set of rules.

However, 65mm (or is it 70mm - can't remember now) emulation is a different story. There are a few have tried it with medium format optics. This offers promises of crisp sharp resolution but there are one or two problems.

The prospect of brightness fall-off into the corners or the "hotspot" may be greater because the widest available apertures over a range of focal lengths in affordable medium format lenses is apparently smaller than the 35mm gear.

Condensors will likely be mandatory. Designing an image erecting (flip) system around a matched pair of optimal condensers into a compact space would be a worthy challenge.

If you have an electronics and electrical specialty available to you, then an oscillating bearingless ring motor of 3mm orbital excursion, not a spinning movement, an internal round clearance whilst running of 36mm diameter ( allowing 3mm for orbital movement ), its controller and its sequenced power supply, slavable to camcorder frame rates from the analogue video out signal could be a project. Such a motor would assist the Letus35 and other very compact moving groundglass systems.

One problem such a motor would encounter is contact friction causing the inner ring to want to roll on the opositve direction to the oscillation, unless a counter-field was used to prevent the ring from making actual contact with a motion controlling surface. Something like maglev trains except suspending a thin metal cylinder between inner and outer fields and modulating them to create the orbital motion.

In other applications, it might be modified as a directly powered trochoid gear drive so the research would not be limited to moving a groundglass.

Making all those tiny magnetic coils could be a real headache though. My estimation is that for a fully dampened no-contact motor, you might need between 20 and 30 coils. There might howeve be microsolenoid coils around now which could be used instead.

There's a bit of homework for you.

[Xander van Manen]

I personally see a future for "small" ccd ( 1/3 or 1/2 " ) camcorders.
the trick in making a well usable 35mm dof converter is the relay lens.
Find a good compact relay lens for canon xl1h, jvc and other camcorders.

[Giroud Francois]

the only problem that has not been solved is the ground glass and lenses matching.
Due to the many combination of camera and lenses and the nature of part supply (more or less: take whaterever you can and try...), nobody has been able to provide a kit of elements that match perfectly (at an honest price).
So repetability of the build process is almost inexistent and the recipe to build an adapter is limited to the respect of some basic optical principle.
for the ground glass, you can get decent result either by purchasing one or making one, but again the perfect GG does not exist.
For sure you can buy many adapters that will give you a nice picture, but that is probably not the point of this thread.
Probably the solution is into incorporating the sensor into the adapter (or removing the original optic of the camera), so even a set of cheap lenses designed for that purpose would outperform any adapter currently existing.

[Stephen Pipe]

Thanks for the suggestions guys.

David and Naoki. I agree man, universal flip is a good idea.

Ben. Sorry about the word 'Revolution'. I agree the camera world will be different in two years time for the high end users but just like when I had to use super 8 as a kid and student I think Kid's and students of the future will benfit from these cheap solutions to film making today. Only my opinion.

Bob. Over the last year you have truly inspired me to make my own adapter. Your technical knowledge sometimes baffles me, but never ceases to amaze me. I think the motor problem is a great area for research.

Giroud Francois. I sent my d screen and a few others down to the univesity and they got all excited about trying to recreate the grain structure cheaply, easily and without the ease of scratching.

Once again guys thanks for the suggestions. i really am looking for as many as possible.

[Bob Hart]

Your groundglass team might like to look at microspheres. There's all sorts and sizes and materials they are made out of.

In a medical intellectual property rights brawl which is playing out in court over here, I have overheard technical discussion on these things. Sizes like 3 microns to 12 microns were being talked about.

Your own university's medical researchers might have some knowings about them. They are also used in automotive body filler.

Maybe there's some glass ones. I understand there is some optical lazer application where they might be glued with UV cure or fused onto a clear panel. That might be a way to go for a new generation groundglass as they would be additive, not subtractive like grinding pits are.

I think there is also a diffuser material for reverse projection TV type applications being made with fine spun optical fibre being chopped up and laid on clear substrate like random fibreglass mat is laid up in boat building.

They could investigate bombarding glass with fine metal particles, then etching them out with chemicals to leave smooth sided round bottomed pits in the glass.

I also overheard the word plasma used in relation to making microspheres.

Another look up is coherent optical fibre bundles for bth image flip and groundglass. They are a dead-end for adaptors at present. Too small for a 24mm or wider image and inferior resolution and maybe some colour wavelength issues. As an image flip, they apparently lose too much light presently. They are used in tube based night vision.

I think the best res Photonis get out of their tubes in their latest evolution is 80 line pairs per mm. I don't know if the limitation is the fibres or the microchannel plate.

As for technical knowledge, I pick up a little bit from here and a little bit from there but not enough of any to do more than dabble.