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Subject: Anyone built their own multi viewer?
Date: 2018-02-23 10:33:04
From: blackiceuk

Are there any plans out there for these for the Realist as a start? Seemed to be a few versions at the time along with one that shuffled the slides.

I need one or a few so best if I can have a starting point.

If anyone has an existing one then could you do me / all a favour and do some comprehensive shots on the inside? I plan on using Kodak/Realist single slide viewer lens elements and go from there.

I've sold my 3d World 120mm 10x slide viewer and 2nd on the to do list is to recreate that as well. From there it will be easy to do a Holmes card version.

What I really could use is a source of the lenses for the steal the light 120mm viewers or the proper name / spec on the lenses.

Cheers

Mark

Subject: Re: Anyone built their own multi viewer?
Date: 2018-02-23 10:53:31
From: Geoffrey S. Waldo

Hmm..
“Are there any plans out there for these for the Realist as a start? Seemed to be a few versions at the time along with one that shuffled the slides.”
To what time are you referring to? It sounds interesting! Is there a thread?
Geoff

> On Feb 23, 2018, at 9:32 AM, blackice@pavilion.co.uk [MF3D-group] <MF3D-group@yahoogroups.com> wrote:
>
> Are there any plans out there for these for the Realist as a start? Seemed to be a few versions at the time along with one that shuffled the slides.

Subject: Re: Anyone built their own multi viewer?
Date: 2018-02-24 04:47:48
From: bbrio1

A good place to start looking for lenses would be Edmund optics (easy to find on Googoo). They have some good and reasonably priced ones including achromatic with focal lengths in the 70-80mm range. Worth a look.

I researched, ordered and received these for a home-made MF viewer, a project which sadly never got off the ground (although still planned) so I don't know if they will work well for what you have in mind. But definitely a good place to start.

Subject: Re: Anyone built their own multi viewer?
Date: 2018-02-25 02:56:28
From: blackiceuk

I got a pair of Edmund lenses. Prices stacked up so looking for another source.

What were the full specs working too on the lenses?

I now have a UK media university briefed and interested so I'll commission my local guy just to do the realist vers - prob do 2-3 at once then when tested we scale up.

Once the 'engine' of the realist vers is made - everything else is scale. Recycling Kodak and a broken Realist viewer for the magnification and focus.

Someone did a stereoscope patent collection which I got from ebay -but I think having the slides/cards locked in place is best compared to suffling them each time it advances.

Also 8-12 seems optimum due to dwel time on the viewer in situ.

Cheers

Mark

Subject: Re: Anyone built their own multi viewer?
Date: 2018-02-25 10:54:26
From: Bill Glickman

Can u describe what u are trying to build..

I spent many years and big $$$ in the design and prototyping of viewer optics...

its quite complex to make high end optics...

I have quite a few completed, ready to build that are incredible...

but they are very costly to build in low volume... to get high quality optics requires 4 - 6 elements which are wide diam and therefore very heavy...

but the view would blow u away...

be glad to work with you..

Bill

On Sun, Feb 25, 2018 at 12:56 AM, blackice@pavilion.co.uk [MF3D-group] <MF3D-group@yahoogroups.com> wrote:

Hi

I got a pair of Edmund lenses. Prices stacked up so looking for another source.

What were the full specs working too on the lenses?

I now have a UK media university briefed and interested so I'll commission my local guy just to do the realist vers - prob do 2-3 at once then when tested we scale up.

Once the 'engine' of the realist vers is made - everything else is scale. Recycling Kodak and a broken Realist viewer for the magnification and focus.

Someone did a stereoscope patent collection which I got from ebay -but I think having the slides/cards locked in place is best compared to suffling them each time it advances.

Also 8-12 seems optimum due to dwel time on the viewer in situ.

Cheers

Mark

Subject: Re: Anyone built their own multi viewer?
Date: 2018-02-25 13:01:35
From: depthcam

> I have quite a few completed, ready to build that are incredible...

but they are very costly to build in low volume...

Having discussed these with you quite a few years ago, it's clear that your designs are amazing. But the cost and weight are prohibitive.

As I recall, we were talking about an over a thousand dollar price range - even though in some of our last conversations you said you had come up with a much lower cost design...

I think that much of the cost however was related to the fact that the aim was to create very wide angle optics that are distortion-free.

Francois

Subject: Re: Anyone built their own multi viewer?
Date: 2018-02-25 14:07:31
From: Bill Glickman

Your recall is very good...

The cost to build multi element optics in low volume, well...its very costly..

If you consider a single element at this size can sell for retail at $40 which are mass produced, multiply this by 5, and add about $150 for a barrel with tolerances required to allow the optics to meet the required specifications. And, all this glass and metal weighs a LOT, about 1.5lbs per eye piece. so hand holding is more difficult, so table tripod would be have to be offered.

So a 5 element eyepiece in a barrel with a run of approx 40 units would be at least $350 each. This is using low cost Asian makers..and with all the design work and prototyping already accounted for. Of course, there is always risk and QC issues adding to this cost estimate.

Considering a high end Telescope eyepiece of similar size and quality cost more than this, and are relatively high volume.... this is the reality of high end optics...

There is no ready made optics, that are ideally suited for MF viewers. It's a very unique optical instrument, nothing else compares, not even binocs and telescopes. With telescope and binoc eyepieces (and microscopes), the optics design is optimized for the center 20% of the radius only. So to see the outer radius of the image circle, you simply move the instrument and re center the object of interest where the optical quality is optimum. This greatly reduces the optical design complexity. However, this is not possible with film viewers, as u must swivel your eye to see off center. This is the foundation of the design complexity, as the eyes center axis of rotation is located 12-14mm behind the cornea, requiring very long ER vs. the other stereo optical instruments.

So, along 80% of the image circle radius the film viewer optical design should hold all the requirements of very high MTF, very low distortion, no chromatic abberation, long Eye Relief for eye glass wearers, and then, a much wider field of view for additional immersion....this is why it becomes such a specialized optic. Its also why the view in VR viewers is very poor. (low pixel count as well, of course)

If low cost is the goal, a doublet will give you the biggest bang for the buck... which I have a few specialized prototypes for these as well, but they are very large, about 60mm diam from memory. I think the lowest fl I hit in a doublet is 75mm. But they will have limited FOV, limited ERelief, and distortion, which can not be corrected at these fls. Granted, the avg person deals with it, as there is no better options. The 3D world viewer IMO was impressive (considering the incredible low cost), assuming you did NOT wear Eye wear, u had very close IPD vs. the optic spacing and could use the sun as a light source.

Its like comparing a pair of 10x40 Chinese binocs for $40, vs. 10x40 Leica binocs for $4K. Are they 100x better... of course not, but they are night and day in optical quality and build quality.

As u recall, this was the reason I pulled the plug on making a run of the viewers years ago... cost became prohibitive. Cost exceeded my original estimates. But I was covering all links the optical chain, lighting (critical to force eye to 2-3mm pupil diam where eye has max MTF), IPD adj with film chips moving with IPD, focus and multi view transport system... well above $2K per viewer cost.

I was not aware of the previous posters objectives for a viewer, I thought he might have a bigger outlook vs the typical MF viewer...

Of course with the rapid advances in display technology, in the very near future, I think the most cost effective 3d viewing solution (incl quality of view) will be with 8K tvs and PC displays...granted, not portable, until 8k displays are in laptops. Mass produced electronics with 32MP will be less costly then one of these proposed high end film viewers. Granted, u will need a mirror viewer to view Side by Side, and wont achieve ideal FOV, due to mirror size limitations, due to, pupil - nose - pupil, spacing. Regardless, based on reasonable ER spec., u can still get up to 35 - 40 deg FOV, which is on par with current MF viewing with typical 75-80mm fl optics. If you add some glass prisms, maybe 5 deg more. But this will greatly effect the weight.

Bill

On Sun, Feb 25, 2018 at 11:01 AM, depthcam@yahoo.ca [MF3D-group] <MF3D-group@yahoogroups.com> wrote:

> I have quite a few completed, ready to build that are incredible...
but they are very costly to build in low volume...

Having discussed these with you quite a few years ago, it's clear that your designs are amazing. But the cost and weight are prohibitive.

As I recall, we were talking about an over a thousand dollar price range - even though in some of our last conversations you said you had come up with a much lower cost design...

I think that much of the cost however was related to the fact that the aim was to create very wide angle optics that are distortion-free.

Francois

Subject: Re: Anyone built their own multi viewer?
Date: 2018-02-26 15:32:20
From: John Thurston

On 2/23/2018 7:32 AM, blackice@pavilion.co.uk [MF3D-group]
wrote:

> Hi
>
>
> Are there any plans out there for these for the Realist as a start? Seemed to be a few versions at the time along with one that shuffled the slides.
>
>
> I need one or a few so best if I can have a starting point.

Mark, can you give us an idea of the breadth of your project?

Are you trying to build a one-off viewer for your
livingroom? Or maybe want to build four and put them in a
gallery? Or are you trying to design a commercially viable
product for resale to the general population?

. .

> I've sold my 3d World 120mm 10x slide viewer and 2nd on the to do list is to recreate that as well. From there it will be easy to do a Holmes card version.

While nice "in theory", in practice I think you will find
the difference in required optics and illumination will
impede simply "scaling up" your viewer for different
formats. MF3D slides, for example, can be viewed with
straight-path optics. Holmes cards require prismatic optics.

> What I really could use is a source of the lenses for the steal the light 120mm viewers or the proper name / spec on the lenses.

At one time, George Themelis had bare 3D-World lenses for
sale. I'm pretty sure the are long gone.

Talk to Larry Heyda, the maker of the Heyascope. At one
time, I think he was willing to sell bare lenses. His lenses
are larger, than those used in the 3D-World steal the light
viewer.

If we're talking about the 'proper name' to use while
designing and discussing viewers, it is time (once again) to
mention medium-format stereo images (MF3D) are made on 120
_format_ film. The film width (and resulting image size) is
60mm. You may call it "120 film", or "60mm film". There is
_nothing_ 120mm about these images.

--
John Thurston
Juneau, Alaska

Subject: Re: Anyone built their own multi viewer?
Date: 2018-02-27 12:28:36
From: Timo Puhakka

At one time, George Themelis had bare 3D-World lenses for
sale. I'm pretty sure the are long gone.
Pretty sure those are sold out years ago.

Surplus Shed https://www.surplusshed.com does have a couple of achromatic lenses that have similar focal length and diameter to the 3D World lenses. I have a couple of pairs of these. One pair is almost indistinguishable from the 3D World lenses. These lenses are priced around $8 each. Certainly a good option if you want to keep the price down. I would recommend blackening the edges of whatever pair you choose to increase contrast (preventing internal reflections will make a similar improvement in contrast).

Talk to Larry Heyda, the maker of the Heyascope. At one
time, I think he was willing to sell bare lenses. His lenses
are larger, than those used in the 3D-World steal the light
viewer.
I bought a pair of these from Larry and they are awesome lenses.

If we're talking about the 'proper name' to use while
designing and discussing viewers, it is time (once again) to
mention medium-format stereo images (MF3D) are made on 120
_format_ film. The film width (and resulting image size) is
60mm. You may call it "120 film", or "60mm film". There is
_nothing_ 120mm about these images.

A stereo pair occupy a combined 120mm of film. Perhaps this film was purpose designed for stereo photography ;-)

Timo

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Subject: Re: Anyone built their own multi viewer?
Date: 2018-03-01 02:45:57
From: blackiceuk

Helllo

I am thinking that I'm going to start with a realist sized viewer - 8 to 12 slides and do 2-3 units.

From there I need my own 120mm version but also a single hand held one as well. Multiple of each. The hand held vers needed for Augmented Reality installation experiments and pieces.

I have a London media University on board now.

Several leads to sell the viewers into for public access.

Still early days so a nice solid yet simple realist version to start with.

Mark