Optical fiber sandwich plate and microlens arrays for shallower DOF?
 

I have two homemade 35 adapters and have bought the Letus 35A flip for my DVX100A. I am also the proud owner of a Bolex Reflex converted to Super 16mm but prefer not to think of the price of film stock, processing and digital conversion here in Norway.
I am quite impressed about Quyen Le's mirror based solution, although the Letus 35A flip mechanism seems quite prone to dirt & dust issues. Hopefully, Quyen is a follow-up angel and problem are being sorted out....and the picture quality is outstanding. With my newly acquired shallow DOF I feel like Jean Rouch or Louis Malle !

I start a thread on alternative technologies, because I have a recurrent and nagging feeling that we (the shallow DOF community) are deploying gargatuan efforts to improve the steam engine in the age of nuclear energy (any better metaphor out there?)....
Here is my point : We should probably look collectively and systematically into novel or relatively novel technologies in order to move on towards substantially better adapters long before the killer 2" CCD with 128 bit color depth appear on the market under 5USD (just kidding ! ).
I suspect that possible improvements in 35mm adapters using intermediate planes, such as ground glass, microwax screens, fresnel type focusing screen (IntensScreen and the likes, Alain Bellon's polycarbonate films will remain incremental and marginal (less or better grain, more light passing through, less luma and chromatic aberrations, better bokeh etc.).

If we (the DOF addicts) want to move on and make substantial progress, I feel we will have to look seriously into optical fiber sandwich-structures (honeycomb array plate) or even better (?) arrays of micro lenses and keep consulting regularly the photonics website. Have a look at the new microlens arrays with selectable DOF !!!: http://www.photonics.com/spectra/tec...ex/QX/read.htm
I suggest this thread could function as a place to review and explore these new techniques.

Why a honeycomb strcuture of optical fibers might improve sharpness radically...
 

Since nobody is picking up my thread (sob) I keep on discussing with myself...

Take a classical ground glass: its microstructure consists of randomly oriented, randomly shaped and randomly sizes micro-facets (not larger than the e.g. 1500 grit allows). These microfacets might, actually, be much tinier than the pixel count of the camera's CCD(s). But color aberration (CA), diffraction, internal reflection between microfacets , absorption and transmission of light across the microfacet wall leads to substntial blurring, or to be more artistique let's call the combined effect of this optical mess: softness

Take a honeycomb structure of tiny optical fibers: each fiber acts as a closed tunnel transmitting light with no diffusion between fibers. Conclusion: Sharpness should exceed widely any ground-glass or microwax solutions.

Do we agree that most of us need shallow DOF and sharpness ?

How much does fabrication of a master cost?

Daniel,

Where can we get our hands on this material your talking about?

I have have some websites links I will will try to dig up from my trillions bookmarks on dof-ology.

OK. Find some companies that produce it and start emailing them for price quotes.

Coherent fibre bundles don't come in 35mm camera frame sizes. Fibre optic wafer viewfinder screens in the past have had problems with colour truth at small apertures, but things may well have come a long way since the CP16RA viewfinder.

Something about your unending knowledge, Bob, has me imagining that when you type responses here, there's the subtle sound the Six Million Dollar Man used to make every time he had to jump something...

Web ste
 

I starting unearthing some alternative tech websites. Here is the first.
http://www.poc.com/

More diffusers...
 

OK we all know good old ground glass
At http://www.knightoptical.co.uk/acatalog/Diffusers.html you will find escription of four diffuser alternatives:
1) Anti-Newton Glass
2) Ground Glass Diffuser
3) Flashed Opal Diffuser
4) Plastic screen Diffuser

Don't they also graft those fiber optic tapers directly onto CCDs in some medical devices? Couldn't it be possible to simply have a CCD grafted with a taper that extends to a 35mm frame and then just have a 35mm lens mount at the appropriate distance. It would probably have to be a 2/3" or larger though.

Sure it involves essentially building a new camera...but most of the hardest work (relay lenses) is taken out of the equation and its all software DSP A/D
(andromedia anyone?).

6 Mill Man. - He doesn't go "pfftt" then "aaah" before he jumps does he? Don't worry, I don't do methane - leastways I don't think I do, then agains, we are ominvores like pigs arent't we.

The coherent bundles. - I enquired with Electrophysics Corp about those.They are used to flip the upside-down image from a night-vision intenisfier tube and I thought they could do likewise for the Agus style devices.

The CP16RA viewfinder is a thin wafer cut from glass fibres stuck together. Heaps better than a groundglass for light transmisson but when you close the aperture, things get colourful in a patchy blue sort of way, but still better than groundglass for focussing and seeing what you will get in the frame.

At knight optical, the finish grade for glass and anti-newtonian glass is stated as 40 micron? We talk 5 micron here most of the time.

I will be content to let somebody else do the research on this one as optical fibres are something I don't understand, like how does the light go around all those bends.

Daniel.

The diffuser kits seem to have some promise for static applications. Have you emailed these people?

The website does not give much away in terms of resolution at the screen surface.

Just chiming in from beneath the mountain of research I've been doing lately...

I would bet that the majority of ground glass diffusers offered by large companies will not match what can be gotten by purchasing your own glass and, say, 1.4 micron aluminum oxide. So, traditional GG en masse is out.

Opal is a more efficient "flash smoked" diffuse surface, and it may prove to be a more consistent looking screen overall, but it suffers from heavy light loss -- which may be remedied (at least partly) by pairing an Opal GG with a high grade fresnel. Bill Maxwell of Maxwell Precision Optics probably makes the best among the fresnels out there, the Beattie people a close second. But be forewarned, they are expensive ($145 each) and extremely fragile.

Be carefull with Fresnel screens, although they're excellent in terms of light transmission, they're also prone to "ring artifacts" invisible on small LCD's when shooting but quite apparent when viewing full screen.

I would suggest choosing a Maxwell Precision screen without the Fresnel & using a DCX lens to eliminate the hot spot. I've spoken with Bill at length about this option, unfortunately he has no such product "off the shelf" but he could make them to order - very expensive for a one-off but in quantity, (25+), the price drops dramatically.

Thorlabs are now doing 1" engineered diffusers, but unfortuanely not 2" - which would have been perfect for us 35 home-brewers! I've talked to the supplier here in the UK about supplying a 2" version, however the costs are prohibitive...

"£400 set up charge, then around £130 each piece. The lead time would be around 2-3 weeks from order. They can also supply square float glass (2mm thickness) or round and square polycarbonate substrate at 3mm thickness.