<<<-- Originally posted by Daniel Moloko : http://www.bobflash.com.br/franquias/recife/locais/barrozoclub/eventos/24-12-2003_3147/fotos/124306.jpg -->>>

Daniel, it looks good. Could you post a full resolution still image without color correction? I'd like to have a reference to compare. Thanks.

i cant post it on the site

i dont have where to post also

anyway, i can send you a email.

tell me yours adress...

ciao

email: coppercapt at yahoo.com

Daniel's image is up at

http://f2.pg.photos.yahoo.com/ph/louisfeng@sbcglobal.net/album?.dir=/35mm+Video+Still+Images

Can we see some footage, too? I've got server space -- I'm willing to lend space for files 15mb and under.

Drop me an email here: jim@ideaspora.net

- jim

I have got my prisms (roof+penta combo) from the links posted earilier. It looks like they will work. I'm working on a draft design right now and once I have it done I'll post it. But it's probably going to be something a little bit more complex. But you can strip it down or simplify it to fit your need. Actually the static version can be very simple if producing upright image is not needed, you only need a ground glass and two condenser lens to remove the hot spot problem.

Since I'm producing a physically correct 3D model, it's possible to create actual product from it. I'm planning to send it out to make a prototype in plastic.

My new material has not arrived yet, but I was told that it has a feature size of around 1 micron, comparing to the finest GG I produced at 3 micron. Plus it transmits much more light than ground glass. This sounds very promising. It should arrive any day now.

vendible,

i just spoked yesterday with the guy who knows optics, and he will find also 1micron GG from some russian military equipment... not bad.

did you tryed to work WITHOUT PENTAPRISM? since dove prism already inverts the image? am i correct? or in dove prism case - image is upside down AND turned left to right?

IF... dove works just upside down - you don't need prentaprism.

just dove and GG, and that's all...

i mean if you have following situation:

35mm lens -> (image upside down) ->dove (image corrected) -> GG ->camera... it means that everything should be allright... or not?

you mentioned somewhere in the thread that dove should be at least 150mm long to acheive 24x36mm frame.
BUT!!!!
film (cinema) frame is just half of that!
so, does this means that shorter dove is possible?
just a thought...

please, correct me if (or where) i'm wrong

filip

Filip,
Actually the image produced by the 35mm lens is both upside down and left-right reversed.

So the image must be both inverted up-down and reverted left-right. A dove prism only inverts the image up-down, not left-right. So you do need a way to revert the image left-right in addition to the dove prism.

Considering a roof/penta combo costs much less than a dove prism alone and without the need of additional instruments to revert the image left-right, the combo is a better choice. Another even cheaper one is the roof penta/mirror combo (the origenal method used in SLR camera), which could be even better.

Also after playing with the roof and pentaprisms, I realize although the roof prism is smaller at 28x28mm compare to the pentaprism at 24x35mm, it's possible to "see" approximitly the full frame passed from the pentaprism of 24x35mm. I know this is not very easy to understand and I was concerned before actually see it.

This more or less confirms why the roof-penta prism in SLR camera allows you to see the full image even when it has one side larger and the other side much smaller.

Honestly I don't know much about the film/cinema frame spec. I only see the standard 35mm camera produces frames of 24x36mm. What kind of lens do you use for half of that frame?

How is that you create the 3 or 1 micron GG ? Seens like here in Guatemala getting alliminun oxide is almost imposible, but still looking. Want to give this a try or o will try making a round GG just like the CD to but made from glass and with really low grain.

Agus, I found this site and it's also posted by someone else in the Homemade adapter thread. http://www.phototechmag.com/previous-articles/2003/mj-dokas/dokas.html

I bought the 5 micron and 3 micron aluminum oxide dust from the company mentioned in the article, Willmann-Bell, Inc. (800-825-7827). I don't know if they will ship international, but it's a good possibility.

For those want to make their GG using these dusts, you are better off buying those 1/16 inch thick glass (the thinnest I can get from a glass shop) at larger piece. I have a 6 inch rotary palm polisher for polishing cars. I use one round piece as the sander and use super glue to glue it on the polisher. With that to sand a bigger piece of about 7x7 inch. After you finish sanding it, you can cut it to fit your need.

The 1 micron material is totally different. I can't produce such thing, it's not made of glass and is less than 1mm thick.

From what I understand, the 1 micron and smaller grain sizes are all diamond... at least that's all I've been able to find that small. In the article Vendible just mentioned, it says diamond is too hard on the glass and causes big gouges that are easily noticable in the image. I've been thinking about giving it a try anyway, just to see what happens.
http://www.facetingmachines.com/polishes.shtml has some very fine diamond compounds, sprays, and slurries (dust & lubricant). Appearently, these are used for polishing purposes. Basically we're trying to get as close as possible to polish without actually polishing the glass. So maybe 3 micron is the best option until Vendible finishes his experiments with the coating he bought.

Ideally, we'll be able to grind/coat the flat side of the first plano-convex condeser lens. That would eliminate the plain piece of glass but accomplish the same result (much like the SLR's ground fresnel lens).

<<<-- Originally posted by Vendible Book : Filip,
Actually the image produced by the 35mm lens is both upside down and left-right reversed.

>>>>---

i think you are wrong on this. maybe i do not understand something, but if you extract (in SLR cameras) mirror, and penta roof prism - what you get? just the image which is upside down. i just took the lens from my AGUS35 and looked thru it - yes, it's of course upside down, but when i turn my head upside down, i can read everything thru this lens. i also tested it with frosted CD (just to be sure everything is checked) - and the image is still upside down. but not reverted left-right.

>>>>>>-- (Vendible's quote)
right. A dove prism only inverts the image up-down, not left-right.
>>>>>>>

so if above is true for dove prism (i cannot check it right now, i beleive i will found it in next few days, when i receive dove for testing) - that means - no need for pentaprism, roof or no roof.

>>>>>>-- (Vendible's quote)
Honestly I don't know much about the film/cinema frame spec. I only see the standard 35mm camera produces frames of 24x36mm. What kind of lens do you use for half of that frame? -->>>

i didn't thought about any specific lens. i'm using "normal" 35mm still camera (read cheap) lens for testing etc.
i just said that film frame dimensions are:

1.33 Full Gate 24x18mm

(1.33 stands for proportion of the frame - 24:18)

that is two times smaller then normal 35mm still cameras frame, so this means that we can still zoom into it and to have proper image - compare to film (cinema) frame size. and if you are talking about roof prism and your experiment - even with the smaller frame - it is possible to reach film look... i hope.


filip

p.s.

happy new year

The home-made ground glass instructions are interesting, and they've inspired me to return to an abandoned project. For a while I've been playing with a C-mount adapter - like a 16 mm version of the 35 mm adapters. The depth of field is, of course, greater with 16 mm than with 35 mm (especially full-frame) but you can get very fast 16 mm lenses - 25 mm f/0.95 and 16-44 mm f/1.1 for example.

The other advantage of 16 mm is that it is easier to avoid darkening around the edges of the frame. A 20 mm diameter plano-convex lens can be used as the condenser. I've got my system to work with an aerial image (ie no GG), but the penalty is great depth of field: the video lens can focus the 3D aerial image too well.

Apart from a shortage of spare time, I've been putting off grinding the plane surface of the condenser because I didn't think that I could do it well enough. Having read Vendible's posts, I now feel like risking it - testing on a piece of plain glass first.

My existing adapter works with an image about 10.5 mm x 8 mm - just larger than full-frame Standard 16 (most Standard 16 lenses will cover a little more than the full frame). If you divide the frame height and width by 3 microns, you get about 3500 x 2500. That seems to suggest that the grain should not be visible if there is no light shining on it other than from the image. I'll test first, because it seems to good to be true and I wonder why it was visible when Vendible tried it with a much larger frame.

The final part of the adapter is a Hoya 10 diopter 55 mm c/u lens. I got the standard C-mount parts, condenser lens and mount from Edmunds.

Best,
Helen

Helen, what focal length condenser lens will you be using? are you planning to use a fresnel and condenser, or two condensers?

Nicholi,
The current version has a single 20 mm focal length, 20 mm diameter plano-convex condenser.
Best,
Helen

I have posted my new design
http://f2.pg.photos.yahoo.com/ph/louisfeng@sbcglobal.net/album?.dir=/35mm+Adapter

The cost of making these plastic parts for prototyping will cost over $250, ouch. I guess I'll make my hardboard version first.

colonia35 zenit
my footage from january 01.

look

http://www.moorefilms.com/dtest.htm

to me it looked GREAT.

the best i can get from a trv18 with the 35mm adaptor.

ciao

OK, it's finally here! This new material I have been talking about is the Holographic Diffusers.

Benefits:
- High diffuse transmission efficiency (over 90% light are transmitted)
- Very high diffusion quality, details are not blured! At the same time, the hot spot problem is gone, no fresnel or condensor lens needed. (Can you believe it?)
- Very thin (less than 1mm thick) and flexible

I was hesitate to tell people because it's not cheap to test them out and there are many varieties of it. I have a picture of it with my other parts here

http://f2.pg.photos.yahoo.com/ph/louisfeng@sbcglobal.net/detail?.dir=/35mm+Adapter&.dnm=DSC00142.jpg

It's certainly better than any of the ground glass I have seen or made, even the 3 micron ones. I don't have a footage yet. But I have seen what it can do and I'm very excited. People probably aren't willing to spend $100 for a 2x2in piece at this point, since you haven't seen anything made from this material.

Edmund sells this kind of diffuser (but I didn't get it from them). See http://www.edmundoptics.com/IOD/DisplayProduct.cfm?Productid=1363

It's going to take me at least a week (2 weeks more likely) to complete a prototype and shoot some videos. Another reason you might want to wait is if it's good enough, many people might want to buy it and I can get them at a much better price.

That's excellent. I will admit I've been a bit hesitant to buy everything for grinding glass just in case your diffuser idea worked. It sounds very hopeful, good luck with the prototype.

A note about Holographic Diffusers, they are very easy to scratch, must be handled VERY carefully. Try not to get your figure prints on it and don't try to wipe it with cloth even if it's soft cloth.

If anyone is interested to order this together, please let me know. I can get them at OEM price of $50 each 2x2 inch piece if there are over 25 orders.

You already got the stuff... what dispersion angle did you get? I have been in contact with the company for about a week and a half... so far it seems the best angle is 80 degrees for complete elimination of vignetting over the entire 35mm frame...

Anyway, I certainly would be interested in getting an OEM price, as I was considering getting the stuff anyway...

What are the prisms that you got there? Once you get it all together would we be able to bulk order them also for that OEM discount?

I'm really anxious to get this all started, especially as I got a short film to start shooting in about 2 weeks.

Louis,

How thick is the diffuser itself? You have said that the material is less than 1 mm thick - but is the diffuser a thin coating on that, or is the diffusion medium that thick (like opal glass)? I'm asking because I suspect that it is very important to have an extremely thin diffusion layer (ideally infinitesimally thin), otherwise the image will be soft. Is it a very thin layer of photopolymer on a thicker substrate? It sounds ideal.

I'm also surprised that you don't need a condenser - that baffles me a little, but it is late after a heavy day. Are off-axis rays diffused towards the axis? Magic indeed!

Best,
Helen

Helen,
The whole diffuser is 0.1 mm thick, the coating (diffusing) surface is much thinner. I mentioned before that the feature size of it is about 1 micron.

Nathan,
This Holographic Diffuser (HD) is very interesting, the one I have is the 80 degree version. After some test, I'm very happy with its diffusing ability, since it completely removes the hot spot problem by itself without any help from condensor lens. The quality of the image is superb and there is no visible grain.

The diffuser itself transmits over 90% of light, but this 80 degree version diffuse light to all directions within 80 degree, that's a lot of light going everywhere. So comparing with a fine ground glass I have, the camera actually see a darker image with HD.

I want to get one with 10 degree or 40 degree to see if they will direct more light into the camera. The only thing is, I was told that with the smaller degree, the feature size goes up (up to 10 micron). But I think it's worth a try before we decide which one to order.

Louis,

Given the nature of the 'features' I wouldn't be surprised if you could get away with them being 5 to 10 microns without them being visible to a miniDV camera (when the image is 24 x 36 mm). After all, 36 mm is 3,600 units of 10 microns - about five times the number of pixels across a DV frame.

This appears to be the magic bullet - well worth 100 dollars a sheet!

Best,
Helen

louis,

this is exelent news. so exiting!!!!

i feel that we all are kind of underground group and working in secrecy to show one day - ta-dammm - it's here!

i'm desperate to see the results, but from the other hand, now i have SO big need to do some tests - since my guy who knows optisc asked me by the way about holograms, and i IGNORED!!!! that part. now, i know that there is SOMETHING which can be used from holograms.

by coincidence or not the very first part of the world HOLOgram means:

PREFIX: Whole; entire; entirely
ETYMOLOGY: Greek, from holos, whole !!!!

so that HOLO means that you have all parts to build it! :)

so, good luck, and share the news!

filip

So maybe Vendible, or Louis (I can't figure out what to call you now) is designing the new Holo35 or 35mm Holodaptor ;).

I've been following these developments with bated breath since the Agus 35 developments. I realize I'm waiting in the wings on making this 35mm adaptor but I've got a feeling Louis is going in the right direction with the holo-diaptor.
Good luck and keep it coming.
I kind of think Holo-mini 35 is a good name for the unit.

I think the holo35 is going to work. I will join in on a power buy
when we have a parts list .

I was really just kidding around with the name. This is Louis's idea, experiment, and money, so he should have the honor of naming the adaptor.

<<<-- Originally posted by Richard Mellor : I think the holo35 is going to work. I will join in on a power buy
when we have a parts list . -->>>

Great, when people want to buy these diffuser together, please post the number of diffuser you like. I'll add them up and post the current number somewhere.

One thing about the diffusers, is they need to be taken care of very carefully, even more careful than you would with your Nikkor lens. Emund's web page has instruction on how to clean it. basically, you would only use water and air to wash and dry it. After a few scratchs on mine, I think it's best to keep them in the plastic bag it came in and only take it out when you are ready to put it in your adapter housing, and never touch the surface (hold with the edges).

Because they are very thin, you can cut the 2x2in (51x51mm) piece into two 25.5x51 pieces, since you only need one with 24x35mm. With the extras on the left/right, you can use paper(or something else) to sandwich the diffuser in between, and then you can stick it on to your housing.

The prisms I got are from the links Nicholi posted earlier in the thread. The cost me about $55 in total. Not perfect quality but certainly useable and worth the price. If you can find a roof-pentaprism, then you only need another front side mirror, basically the same setup as the 35mm SLR camera (see the photo I have in my photo gallery).

I'm getting a 10 and 30 degree HD to see if they will improve the image brightness.

I'm in for two. The basic element is to determine which would be better. You mentioned that a 10 to 40 degree element might be better suited to concentrate the light more directly into the lense of the cam. I await you experiments.

As I mentioned before, I'm in for one diffuser too.

As for flipping the image, I think there is a way to rotate the image 180 degrees with a series of 4 mirrors. If anyone knows where to get cheap 45 degree mirrors (90 degree image deflection)...
I think finding the right size mirrors to get the entire 35x24mm frame would be a lot easier than prisms... and there aren't big pieces of glass the light goes through either, as we do need to conserve as much light as we possibly can.

Anyway, I would assume that optical mirrors would be loads cheaper than these prisms.

Current group buy list

http://wwwcsif.cs.ucdavis.edu/~fengl/diffuserbuy.txt

i suggest to keep updated list on the very same site as you mentioned

http://wwwcsif.cs.ucdavis.edu/~fengl/diffuserbuy.txt

but to contact you via your e-mail. it will be easier (i think), then to use this thread just to say : i'm also in, need ... pieces etc.
after, say, 20 people replies like "me too, me too" nobody will find the real thread here.

let's discuss the proper things on this thread and contact you directly when hologlass is needed?

is this ok with you?

(by the way, i'm also in - for two pieces.)

filip

Filip, that sounds good.

So anyone interested just email me with number of pieces. I'll add it to the list. I can be reached at coppercapt (at) yahoo.com.

Am I correct in assuming that this order won't be purchased until after you've figured out the most usable angle of diffusion? I don't mean to sound like a jerk, but I tend to be a bit skeptical about everything. I am waiting until you finish your experiments, but I do plan to be in on this group buy as long as I'm getting the right stuff. Just making sure before I send the official email :).

<<<-- Originally posted by Nicholi Brossia : Am I correct in assuming that this order won't be purchased until after you've figured out the most usable angle of diffusion? I don't mean to sound like a jerk, but I tend to be a bit skeptical about everything. I am waiting until you finish your experiments, but I do plan to be in on this group buy as long as I'm getting the right stuff. Just making sure before I send the official email :). -->>>

Certainly, if it doesn't work, I won't buy any myself either although I did get them for testing. This is not a promise or any kind of contract. It only tells how many people want to get it IF it works and gives hope to get them at OEM price. I plan to post videos without any modification and full resolution snapshots before we decide whether it's good enough. I know many have posted their videos with color corrections but I don't think it shows exactly how good/bad it looks. In fact I'm going to video the same thing with and without the adapter to compare the quality and light loss.

If it doesn't work, then we'll look for something else. I have nothing to complain about the holo diffuser I have at 80 degree other than it is not bright enough. It solves all other problems (image quality, hot spot etc.). As I posted earlier, a 10 degree and a 30 degree diffusers are on their way to me. I suspect they will improve the lighting dramatically but I'm uncertain about the grain. If the 10 degree version doesn't make any visible grain, then I think that's the way to go, since it will be the brightest of all holographic diffusers.

I also notice and Helen has also mentioned, those light stops on the lens are quite important. I have a Nikkor 35-70 with f3.5, that's a lot less light compare to my Fuji 35 with F1.9. Get lens with smaller f number if you can.

I'm having my fingers crossed.

louis,

i bought on sunday on the second hand photo market rare piece of russian lens, as i was told it was used on russian cosmic program (spy?) it's a huge ang weights "a ton" - and has f1,5. which makes picture VEry bright in my adapter. i agree that "f" is very important. keep this as low as possible! (which also helps in shallow DOF).
just a thought.

filip


p.s.

(O.T.) if someone is curious how it looks - i can send the picture to louis.

Here is the link to Filips frosted CD 2 for 1.

http://www.moorefilms.com/frosted.htm

sampling frequency (Niquist) theory says you have to sample at 2X the frequency to capture all the detail. However you may still capture multiples that coincide with pixel frequency.

So the comment about DV not having enough resolution to capture the full details of the diffuser is correct. Also because the width of each line is so much less than the width of a pixel, I think it's unlikely that artifacting of coincident multiples (like a morray effect) would happen.

I've lately built and automated film recorder and have been working out my video production chain.

My camera is a DVCPRO25 which has a removable lens and I'm already doing a lot in post to get things right for xfer to film so all the optics besides the diffuser are out of the question for me.

Having just found this thread and Agus' thread. I think static is the way to go for a production environment friendly piece of equipment. Not to mention I don't want to have an injunction slapped on me for shooting a movie with someone elses intellectual property.

I definately plan to build one of these babies.

Thanks to everyone who got in early.

Can someone explain to me what the degrees mean in reference to this holographic glass? Does it mean the glass has to be slanted at that angle when put in your design? Or does it just mean that something in the glass itself (the granule's?) is slanded at that angle?

thanks

I've been trying for a while now to find information clarifying exactly what Mike just asked. All I can find is information on "scattering angle." Diffusion and scattering basically mean the same thing, so what I think is that the angle of diffusion represents the amount (specifically angle) that the visible area of image is projected onto the diffuser. Basically, when you look at the back of a lens, you will see only a small circle of the image coming through the lens. This is because you can only see what is directly in your line of sight, directly in front of your eye. As you move your eye in a linear motion side to side, still remaining the same distance from the lens, you will see different areas of the image coming through the lens. The diffuser takes the infinitely different "angles of sight" and concentrates them on one area - the ground glass/diffusion surface. The angle of diffusion causes a variation in how much is being diffused.
Okay, now that I've confused everyone, including myself, here's a link... http://topcontechnotes.home.att.net/viewingsystem/page4.html.
Hopefully, someone has found some other information regarding this question that either proves or disproves my theory.

My understanding of this term (and most likely to be correct) is it's the angle of the viewable area. This measurement is also used for LCD screens and projector screens. When you are within the specified angle in front of the screen, you will see an acceptable image, if you are outside of the area defined by the angle, you will not see the image correctly (too dark etc.), and the reason for that is light are not scattered (enough) to the areas outside the specified angle.

For some applications, you want to have a wider view angle for the screen, for LCD and projector screen etc. so that more people can see the image.

So the holographic diffusers can control where to diffuse the light and control the area where it targets to.

That makes sense. Which would indicate, like you plan to experiment, that a smaller angle of view would provide better results due to the camcorder lens always remaining at the same "straight shot" angle. Am I understanding correctly?

That's exactly what I think.

If I have understood the formula for the angle of diffusion given on the POC website correctly, the amazing thing about the holographic diffusers is that they diffuse off-axis rays less than on-axis rays. For example, with a 10 degree diffuser, a ray hitting the diffuser at 40 deg to the normal will only be diffused to a 2 deg cone. This appears to explain the lack of hot-spots and it also suggests that a small-angle diffuser will work if the rest of the system is correct.

I'm attempting to have a discussion on this with the folks at POC (they make the diffusers sold by Edmunds et al) but haven't had much luck so far. I think that I'll end up getting the 10 degree sheet and testing it myself. As I've already mentioned, my current setup works without a diffuser as far as even illumination and full frame viewing goes, but it needs a diffuser to form a single image plane instead of a 3-D aerial image.

Best,
Helen

Thank you for answering that question. Makes sense now. Sounds like it should work out great. I'm excited to see the results.

I have a couple other question though:

http://f2.pg.photos.yahoo.com/ph/louisfeng@sbcglobal.net/detail?.dir=/35mm+Adapter&.dnm=DSC00142.jpg

The prism at the top of the image. What kind is that and what will it do? Is it the same type speculated to be used in the movietube design where it will flip the image but the camera needs to be mounted at a 45 degree angle to it? If so that doesn't sound that bad. Might even be kind of nice ergonomically to have the camera slanted. At least for my camera which is a vertical design and could use some extra space at the bottom.

The prism at the top of the page with a smokey black surface is called a pentaprism. Basically it reflects the image 90 degrees but doesn't invert or revert the image (utilizing two reflective surfaces to accomplish the 90 degree angle). That's what we're using to make the camcorder located at a horizontal angle.
Not much is known about the MOVIEtube yet, not even the price or availability. My theory, however, is that they use a Schmidt prism (http://www.edmundoptics.com/IOD/DisplayProduct.cfm?Productid=2430) which inverts and reverts the image (which is what we need), yet deviates it 45 degrees. That means the camcorder would have to be located at a 45 degree angle in order to properly capture the image. The prism might even provide the required distance from the 35mm lens to the diffuser surface which would make the adaptor much shorter. The camcorder lens could be right up to the diffuser, almost as close as a filter? At least that's my theory.

Here's a neat link that has drawings, characteristics, and names of many different types and variations of prisms.
http://www.tecplusplus.de/ManualLu/prisms.htm

Ultimately, the mirror/roof pentaprism would be a great solution. Right now, I'm using the prism I pulled out of an old SLR camera. Unfortunately, probably to save space, the "roof" is right on top of the "floor" surface. Many of the drawings on the internet show a distance between the two surfaces (like a house with walls), however mine only has a small distance (like a roof on the ground). This will still work fine, but I have to place the prism further away from the diffuser in order for the camcorder to zoom in far enough to capture the entire frame but not be cut off by the roof. That makes my adapter really tall, which I'd hoped to avoid. Maybe SurplusShed will get in a shipment of roof pentaprisms exactly like we need. Here's hopin' :).