Working towards a solution at reversing the image the Agus35, I had already picked up one of these great gadgets http://www.zgc.com/zgc.nsf/active/6FA3DA5F0C16A24985256B82007B576D a little shock absorber/mic/eye-piece extender. So to right side the image all you have to do is flip the mic/eyepiece arm to the other side of the support T and turn off the evf display. I'm still awaiting a few key pieces to build out my Agus35, I will be on vacation for the next few weeks but I hope to show pics and tests of my mod the early week of january.

D

I have no plans of my own for building an Agus35 yet and I'm not an expert in optics, but here are my thoughts on the subject just from having read through the thread--

- The name of the game in building one of these should be preservation of light. Additional generations of reflectance/transmittance are going to substantially reduce the amount of light that gets to your CCD.
- To that end, why fool with mirrors to invert the image. This is something best done in post. If you're having a hard time visualizing on the set, put the inversion apparatus outside the camera after the viewscreen/viewfinder.
- Similarly, it's hard to imagine the amount of light reflected from a built-in white screen (as in Paul's diagram on his web site) would be as good as what's being transmitted through a ground glass.
- Someone mentioned using something other than a frosted CD as a ground glass. The nice thing about the CD is that it's already very round. Use anything with a center of mass in a different spot than the center of rotation and your implementation is going to vibrate like the dickens.
- When's the XL2 coming out again?

<<<-- Originally posted by Danny Tan : nice page. but i think if you have fresnel lense, then you don't need the magnifier cause they just do the same thing. correct me if im wrong -->>>

yea thats wrong.

The Fresnel lens is to even out the light recieved from the 50mm lens, so you dont get a really bright spot in the middle of the GG.

The Magnifier (macro lens) is so you can get your DV camera really close to the GG and be able to focus a clear image on the GG.

------------------------------------------------------------------------------

Please people- read the previous posts, I know 28 pages is daunting but its really not that hard.

"- Similarly, it's hard to imagine the amount of light reflected from a built-in white screen (as in Paul's diagram on his web site) would be as good as what's being transmitted through a ground glass."

Indeed: at best, Paul could get a regular 1.0 reflection rate for his screen. Spinning disk implies he can't get any sort of gain for his screen, because gain would make the screen highly directional. "No gain screen" means the light is gonna end up being scattered everywhere, in every direction. So lots of photons are gonna be lost in the process of reflecting the picture.

Furthermore, I just can't see how he could possibly get a correct picture geometry with this setup... The adjusting process must be daunting. Paul must be ending with a very dim and somewhat distorded picture IMHO.

Paul, why don't you take the "KISS" approach (Keep It Simple, Stupid)?

To: Jim Lafferty.

Jim.

Perhaps we should talk about two distinct functions which happen and call them stage one and stage two.

Stage one is in effect a camera and setup (= AGUS35 system). -- Object>>>lens>>>focal plane |, in this case it's the groundglass.

Stage two is another camera and setup. -- Object, in this case the image on the groundglass>>>relay lens or close-up lens if needed>>> camcorder lens>>>focal plane |, in this case, it's your camcorder's CCD chip.

It sounds to me like your problem is in stage one. You have your 35mm objective lenses too close to your groundglass. The rears of those lenses must be the same distance forward from your groundglass as they would be from the film plane (focal plane) if still installed to the cameras they came off.

This distance will be in the ballpark of about 1 and a half inches or so, not the half-inch of so you are using. To get the exact measurement, grab the camera bodyn dismount any lens you have on it and look for a mark on the top to left of the viewfinder prism enclosure for the Nikon (FM2).

The mark will be an "O" with a line drawn through it. This line corresponds to the focal plane (film plane) of your 35mm camera.

Put a straight-edge (a ruler is fine) across the lens-mount face of the camera so that you can then measure the shortest direct distance from the focal plane to the edge of the straight-edge. That distance is the space which needs to be between the mount face of your objective lens and the groundglass. Once you get that right things should start to look a lot better with a sharp image projecting on the groundglass you can see with your eyeball.

The issue from that point will be stage two, being able to frame and focus sharply upon the image projected onto your groundglass.

Between your camcorder and the rear of the groundglass is where any of the close-up lenses, macros etc talked about here will have to be placed if your camera cannot frame close enough and hold sharp focus on that projected image on the groundglass.

To initially set this part up, forget about trying to project an image onto the groundglass and use a barcode panel off a food packet to see if you can get your camcorder close enough. The barcode will show any distortion of focus defects.

Once you've got that sorted, then you can mate up stages one and two with a lot less grief, knowing each of the stages in themselves are working properly.

This leaves you with the task of rotating your groundglass and putting the whole thing inside a nice looking enclosure. Don't forget to paint the inside with blackboard paint to eliminate internal reflection which may cause a fogging effect.

If your groundglass is not opaque enough, the image into your camcorder will have a hotspot in the centre, most evident when your objective lens on stage one is stopped down.

To all:

Best frosted effect with the plastic CD disk is achieved by finding a flat surface, (sheet of glass on a benchtop) laying on it a piece of dense soft cloth which is not going to scratch the smooth side of your disk, placing face-down on your disk, a sheet of 500 grit silicon carbide (wet and dry) paper, using a short screwdriver handle or similar blunt object with both round and straight edges, then scrubbing away to press the grit against the disk. Do not let the paper scrub across the disk as you want pits, not scratches in your disk. For the broad surface of the disk you can scrub the ridged grips of the handle across the paper. Towards the edge of the disk you will need to use the rounded end of the handle to scrub with as the disk rim is slightly raised and the frosting effect will not reach the edge.

It will take you about 80 minutes of patient work. The job will be done when you cannot see through the disk but a lens will project an image on it.

Cleanliness is next to godliness and most importantly, do not touch the ground surface as finger grease will spoil it and no amount of furthur work will remove that smooth mark. Efforts to clean it will polish the groundglass pattern because the plastic is soft.

cosmin rotaru says in a early post to agus that he should use a fresnel lens in order to get rid of the hot spot on the GG. Another user posted a link to an american store who sells fresnells, i live in europe and i have not been able to get a fresnel to eliminate the hot spot on my agus35. does anyone know where they're sold in europe? or perhaps another device where they can be taken out?

thanks

Thomas

Use a dove prism to flip the image.

http://www.doveprism.com/

I've used a 25 cd spindle box, and a 50mm lens. But when I have the lens focus all the way in, I need the ground glass to be as far from the lens inside the spindle box as it can to focus on anything thats about 2-3 metres away. Anything closer than that and I can't focus.

Any ideas?

Thanks

I experienced something similar, and it's one of the trials of experimentaion. If you look at Agus's design, you'll note that there's an extender between the front of the adapter and the back of his 50mm lens -- bringing the rear of his 50mm lens about a half to three-quarters-inch away from the adapter's surface.

Likewise, his motor is mounted at the front of the adapter, with the spindle facing back toward the DV camera -- with the CD mounted at the tip of the motor's spindle, placed very close to his macro lens.

I did a quick-n-dirty mockup last night with a 9v battery hooked up to an on/off button and my motor and ran tests with the GG within a half-inch of my 50mm lens, and then as far away as I could get it inside of the CD case -- in order to get focus on the GG, your film lens must be placed 3-4 inches away. Maybe slightly more. Experimentation will find your answer.

- jim

I measured my SLR camera from the front of the body where the lens mounts to the film plane, the distance came out 46mm, I adjusted my box so the distance matched to the GG. I still haven't tried any video yet, I haven't made mine light tight yet, too much to do and never enough time!

Tom

Has anyone made one of these sucessfully for the gl1? If so which macro filter are you using and what are the distances between the macro filter and the gg and the fresenel lense and the 35mm lense?

I can answer your questions with partial confidence, as I'm about 85% done my GL1 adapter.

The macro power should be +7 or greater -- this allows you to move your camera in close enough to the surface of the GG and still zoom in to avoid vignetting.

I've got probably a half inch between the surface of my Century Optics +7 macro ("achromatic diopter") and the GG. I'm working on having about two inches between the GG and the rear of my 50mm lens.

If you've got a macro, you'll likely not need a fresnel.

However, and this goes back to my comment about partial confidence:

I put together a mock-up of my final adapter design last night and I couldn't pull focus accurately. I'm making an educated guess that this is because of the distance between the 50mm lens and the GG, which I figure was too short. I'm now extending the distance with a rubber ring between the F-mount and the front of the adapter.

Also -- I haven't actually shot anything yet, only looked through the viewfinder while holding my adapter up to the camera. No telling if my guesses, educated or ingorant, will prove to make for a functional adapter.

I will be done tomorrow, and plan to have footage up by Sunday. Check for it at http://ideaspora.net then...

- jim

I don't know whether anyone has already posted this link (http://www.spycow.net/) to a diagram and explanation of the Agus35 CD + spindle concept.

And after we have all this crap put into a box strapped to the camera, we finally have a picture that's more blurry, darker, and harder to focus and zoom. But that's what we want, because it will fool people into thinking you're filming on film instead of video. Isn't photography wonderful?

Not exactly a rave endorsement; nice schematic though. And check out the Fresnel link while you're there.

here is a new video made with a beta version of the adapter
like you can see.. there is no vigneting.

http://altoque.tv/35mmAdapter/35mmtestBETA.wmv

Now we are working on fliping the image for perfect control and making all the pieces to look pretty and profesional, as well as making a pro rod system and baseplate. as well as a matte box.

Not exactly a rave endorsement; nice schematic though. And check out the Fresnel link while you're there.

Of course it's not a rave endorsement. The footage still isn't perfect because the device is still in development. But even if it were done like the Mini35, it's still harder to focus, blurry (because the background is in focus), darker (this adapter doesn't create light, you know), and we're doing it to try to make it look more like film.

Of course, I meant that ending line rather tongue-in-cheek anyway (yes, you linked to my website. Thanks. :) ). When I have the time, I want to make one of these adapters myself. And thanks about the schematic. I haven't put the macro lens nor any flipping scheme into it yet. Actually. I'll do that now.

Edit: Wow. Agus, that footage looks amazing. I had some doubts after some of your earlier footage, but that last clip really does look wonderful.

Edit 2: Near the 3:30 mark on that footage and onward, I could start to make out the edge of the hotspot on the edges of the frame. I assume this was because the sun was setting so you didn't have the same light, but how bright was it at the time, and how much light should we expect to have to work with as you have your adapter right now?

I promised I wouldn't contribute anymore to this already gigantor thread, but after reading about someone else (Jim Lafferty) building their own mini-50mm for a GL1, I had to post a question!

Ever since the beginning of this thread several weeks ago I was under the impression that the fresnel between the SLR lens and the GG was solely there to focus the image onto the GG - even in my own "beta" version of the mini-50mm the fresnel performed this action. Jim , I noticed you said "If you've got a macro, you'll likely not need a fresnel." I must be missing something here, or maybe your adapter is built a little differently than mine - but I can't see why you wouldn't benefit from having both a fresnel lens to focus your image onto the GG and having a macro to allow you film something up close. Can you shed some light on this? Also...

You said you use a century optics +7 achromatic diopter. If I had the cash to squander, you'd be certain that'd be my "macro" lens of choice. However, I'm a cheap college student on a tight budget. I remember reading that the century achromatic diopters allow for zoom thru to a certain extent. Regular macros don't pull that off as well, correct? So in essence if you fail to get a powerful enough macro lens to get you close enough to the GG to fill the frame and avoid "vignetting," you wouldn't be able to zoom in and pull sharp focus would you? I guess in this case it's better to overkill and get a +10 macro lens - better to be closer than further?

Anyways, Jim I'm very interested in seeing how your set up looks/works as a fellow GL1 owner. Unfortunately my cam is in the shop for a faulty LCD and so I haven't gotten a chance to test things out, so I'm living vicariously through this thread!

I have followed this thread from the beginning, and was thrilled to rush into buliding mine. I collected all the materials, except lens, and was worried to find that I could not locate a clear CD. All of the ones I had were already frosted. I went through about 5 or 6 of them until I finally found a clear one, I was quite relieved. I should have just tried the frosted to see if it would work, now I'm glad to see that they are preferred. (I hope I didn't throw those frosted ones away...) As far as where to get them from I'm not sure. I know that most of them came from 100 pack spindles, gotten for free after rebate (boy was that a hassle) on the day after Thanksgiving. I don't know if its a feature of the higher count spindles or what. The Discs are old ones, so I'm not certain, but I think there is a decent chance they came from KHypermedia or Memorex. I'm not sure on this, but if your desperately against grinding the CD yourself, it could give you a start.

I am loving this thread! This is the funnest little project to work on, and impress your friends with. My following of this post here has been kind of sparratic, I just got to previewing Aguss's newest beta posting. BEAUTIFUL! I'm about 90% done on mine, 90% as far as consturuction goes. I think I'll have a lot of tweaking to do, so maybe only 30% as far as complete finalization. I've got to run to the local pawn shop and see if I can't find me a 35 mm now...

Chris,

Please, please, please extract pertinent information and post to an Agus35 information thread. I think that would help us all! It would definite help me, because I can't find anything when I need it...

...on that note...I have completed stage one and wanted to offer what I have done and ask a question.

For connecting the box to the camera, I bought a UV filter, drilled a hole that size and super-glued it in. That way, you just screw the box onto the camera (just make sure you have it so when screwed all the way on it is straight! I didn't...learn from my mistake!) Also, you can then screw the macro right into the front of the filter due to their similar thread size! I have been using super-glue with good results...I got hot glue and super glue and decided to use super glue. It has worked great so far. The lens cap that goes on the back was used for the front to connect the lens. Thank you to whomever posted about that idea!

I have recorded footage without the fresnel lens (by the way, thanks Ryan for confirming that the fresnel lens is the same as a reading magnifier...I bought one in hopes that it was) or the spinning glass and it just seems to be darker. I haven't tried it in the day yet or on close ups. I also didn't notice a huge difference in the DOF as compared to footage without the Agus35 on. I hope (and know someone has stated it before, am too busy to read through 450 posts - another reason Chris!) that someone can tell me that the GG and fresnel will give me the DOF Agus is getting??? Please tell me this is what is missing for the DOF! If so, that's what tomorrow will be...a quest for DOF. Sorry for the long post. Thanks in advance from my fellow Agus35er's.

Clay

Hey, I've been following this thread and im scheming out my own little project...

We're mostly all using 35mm SLR lenses right? There should then be no need to put a fresnel in between that lens and the GG, as long as the GG is the same distance away as the film plane for that lens (there was a post on this maybe two or three pages back). If anything, I would think the fresnel would be just like the macro lens (but cheaper)...

Im not sure if I missed something, but what is the order of elements in your device, Agus? Seems like you've got the vignetting problem mostly solved. Does any vingetting become visible when the 35mm lens is stopped down, or filming in low light?

Another thing... Im worried that the box and the relatively heavy lens will pull down slightly, warping the image. Or the whole thing move as I'm filming...
Is there any place I can go to find out how to make a rail mount system, or where I can find specs/dementions of the real ones?

Here is a link that gives FFDs for various lens mounts.
http://www.gregssandbox.com/gtech/filmfacts/flange.htm
There are also tables in the likes of the American Cinematographer's Manual and David Samuelson's Hands On manual - but these are biased towards movie camera mounts.

The FFD is the distance between the mating surface of the body/lens (not the bayonet lugs, screw thread or whatever) and the image plane.

One inch is 25.40 mm.

If your lens isn't there do a search: just use 'flange focal minolta' or whatever because of the various names used for this.

If you want an upscale alternative to using a rear lens cap as your mount, look around for second-hand bellows adaptors. These are the mounts made for using lenses on bellows for close-up work. Try http://www.srbfilm.co.uk/ They also make custom parts very cheaply compared to movie industry places. They export.

Standard 'lightweight' Arri support rods (also used by everyone else for DV cameras) are 15 mm diameter, 60 mm centre to centre. These dimensions have to be very accurate for some standard equipment to fit. The rod axis is 85 mm vertically below the lens axis and the rods are equidistant from the lens axis (at least they are on my Petroff matte box). Some adjustment is usually possible for the exact lens axis / rod axis alignment. Plenty of people offer rod adapters as standard items. They aren't terribly expensive even when custom made.

Best,
Helen

To Chris: The condensing of the thread. Good idea. Soon enough we will be beginning to see thread deja-vu otherwise.

To All: A useless and unproductive curiosity question?

Has anyone added controlled lighting onto the groundglass to achieve an effect similar to that of pre-fogging motion film. It might be interesting in situations where the contrast exceeds the workable range of the DV camera. It might be interesting creatively if different colours were used, even more so if a known colour temperature offset was used and the lighting then adjusted back in post., ie., an effect perhaps similar to using an 81EF filter at sundown with tungsten balanced film.

I must be missing something here, or maybe your adapter is built a little differently than mine - but I can't see why you wouldn't benefit from having both a fresnel lens to focus your image onto the GG and having a macro to allow you film something up close. Can you shed some light on this?

Devin,

Well, maybe you're right -- I thought I'd read something in one of the earlier posts where Agus discarded his fresnel after installing the macro. Now I see, going over the old threads that this wasn't necessarily the case. My mistake, sorry. And so I have to ask -- is everyone using a fresnel and are they helpful?

Agus -- is the fresnel in your latest version of the adapter?

So in essence if you fail to get a powerful enough macro lens to get you close enough to the GG to fill the frame and avoid "vignetting," you wouldn't be able to zoom in and pull sharp focus would you? I guess in this case it's better to overkill and get a +10 macro lens - better to be closer than further?

I think this is all correct. I'd go with a more powerful macro either way you slice it.

I'll definitely keep you posted,

- jim

hello there,

as far as i can see - there is no info about manufacturer of frosted fake cds.
i have suggestion that anyone who knows the manufacturer who is definitelly NOT producing frosted/sanded CDs - to put it on the list, so we will be closer to that real one.

second thougt - does anyone knows how to make CD frosted with some chemicals? maybe this is much simpler than making it "mechanically"

filip

Just picked up a cheap fresnel and it doesn't help me -- at least, not yet.

I'm convinced my focusing problems are a flange focal length issue, but I've yet to find the proper distance between my lens and the focal plane (the GG). It's better, but still not acceptable.

When/if all else fails -- is a longer distance between the lens and the focal plane the best solution?

Incidently, I've got a Nikon Nikkor 50mm f/1.4 lens, part # 3958069. If anyone has the info that Google doesn't seem to turn up for me, I'd love to know...


edit: Helen -- the link you posted was down when I first clicked on it -- the link now works and I see that the distance for a Nikon SLR lens is 1.83 inches. Thank you for the info!!

- jim

The focal plane for the 50mm lens are 50mm away from the lens. That's the distance from the middle of the mirror to the focal point. On the lens it usually says something like f=50mm. If it doesn't say that, I would assume that because it's very common. If you measure the thickness of the camera, it gives a good approximation of where your GG should be.

Anyone find out where the pre-frosted CD's come from? So far from the thread this is what I have:

CD Packs that do not offer Frosted CD's:
Imitation
Fugifilm
Philips
100 pack $20 at Best Buy

Possibly have it:
Khypermedia
Memorex

Please let us know and add to the list so we can find out which pack it is...and then run out and buy their stock because you know they will be selling a hell of a lot of them!

Agus,
That beta footage is awesome! Do you have any recent pics of your new design so we can start drooling for the commercial version? Thanks.

Chemical means of achieving frosted surface on disk!!

Those chemicals might be a little dangerous.
There may be some solutions but it would be irresponsible to post them here.

It could render me and the host of this service possibly liable for suit should tiny vexations like chronic dermatitis, blindness, chronic obstructive airway disorder and death emerge as collatoral consequences.

This is one area I would commend anyone not qualified to avoid like the plague. If you don't know it or can't do it, don't try. Chemicals are very socially enlightened. They don't discriminate. They just drop everybody. Seek help from somebody who has accreditation in this very specialised industry.

So you are going to go for it anyway. Whatever chemical you choose to experiment with, be extremely careful, avoid the vapors and don't leave the stuff lying around for little bro or sis to encounter. And for heaven's sake read the Hazmat notes, know what to do beforehand if it all goes wrong. Devise your personal or household counter-disaster plan if you have not already.

I don't think you will achieve by chemical means, anything you can't do with a lot less risk or hassle with graded silicon carbide grit or wet and dry silicon carbide grit papers or jobbing the task out to somebody who can gritblast with graded grits. That final 5% to perfection everybody looks for might only be achieved by experienced practitioners of specialised crafts.

The frosted CD disks people have been mentioning here?? Are they "frosted" right through the thickness of the disk or only on one surface??

If the "frosted" feature goes right through the full thickness of the disk, you will likely get inferior resolution, a halation effect into neighbouring image from pinpoint highlights and lower light transmission.

If the disk is only lightly translucent, your camcorder is going to also see through it into the front lens and you will get a hotspot in the centre of your recovered image.

There were two versions of the small "Pringles Chips" container press-on caps. One cap which originated from Belgium was a clear plastic with a frosted finish applied to one surface. These containers made excellent pinhole cameras for kids. The US cap was made of a translucent plastic which did not work as an image plane.

Another solution might be to do what they do to make ground glass. It may also work on the clear CD's...just another thought...

Check out this website:
http://www.phototechmag.com/previous-articles/2003/mj-dokas/dokas.html

I am sure there are others, but may be another option.

Bob,

Agus has stated, after using the frosted CDs, that his resolution increased and there weren't any problems. In fact, by his latest footage, I would say he pretty much got it right! Don't know about where it is frosted as I can't seem to find one of these bloody things:( Will let you know if I can ever find one.

Agus Casse <btw Paul, your designs wont work, i tried them and they are no good.>

You are absolutely right! The one or two mirror versions do flip the image vertically but not horizontally. Back to the drawing board. Looks like the only way is to copy the SLR in as far as the light path through the viewfinder.

Paul

For what it is worth - In the past, I have had clear pieces of glass turned into frosted pieces very nicely via sandblasting. I didn't do the sandblasting though, it was done by an ordinary local glass & window service company. The pieces were very consistent with each other and it only took the shop an hour to perform the job.

- don

I have one frosted CD that came in a spindle but I forgot which brand it came i in. It could be Maxell or Primaris. They are definitely not from Fujifilm... :]

http://www.imagestation.com/picture/sraid93/pd6981a3f96a25751b76a28be5b610bee/fa3e9a51.jpg

http://www.imagestation.com/picture/sraid93/pce3cb261f697697c7010e87d21a72c9b/fa3e9a4e.jpg

http://www.imagestation.com/picture/sraid93/pfdfd18bebce77ffb524f1792d72ba330/fa3e9a54.jpg

Well, I got 'er functional today -- she's not pretty yet, and without a rail system in place the image shakes a bit much (going in and out of focus with it.) But, what can I say, I'm proud:

http://ideaspora.net/agus35/agustest.mov

(12.8mb Quicktime 6)

- jim

I am sure that someone has already pointed this out earlier, but here goes. The frosted plastic that you are using in place of real optical ground glass is deteriorating the image too much. It is also causing you to lose too much light. Earlier, someone had posted something to the effect that "if you use ground glass, the image will be too bright". Well, if that is the case with this design, then the design is flawed and should be reworked so that you can use real optical ground glass. So far, none of the sample clips I have seen show an image that does not look degraded by the plastic. No offense, just an observation.

- don

Yeah, but expense and weight have to be factored into the design, as well.

I've got about five "ground glass" CD's here -- they cost me nothing more than I'd long ago spent on CDR's. If I drop them, or decide I want to mess with them to get different optical effects, I don't have to sweat their replacement and the costs incurred.

The question isn't (for me at least) 'How can I get the best image possible, at the expense of other considerations?', it's more 'How can I create an image that's acceptably interesting with the things I have at hand?'

- jim

I would still say that as long as you limit yourself to using plastic in the image chain, you will be self-defeating yourself. Why waste all that energy trying to produce an "acceptable" image with plastic when you have the potential for an excellent quality image with glass? It's a simple thing that we have known for years - plastic does not produce good results in photography.

You mention "expense" - what is your budget cap? C'mon save yourself a lot of frustration and wasted effort, spend a little more and put some real glass in there. I dare say that it is not impossible to find an affordable glass solution by modifying the design a bit. Regarding finding an affordable piece of glass - has anyone thought of using a 2mm thick 4x4 or 3x3 mist or fog filter from LEE Filters or Cokin? Or perhaps an even-more-affordable resin filter from LEE or Cokin? Even a resin filter would be much better than plastic - but you really should use glass.

Again, no offense implied here, I'm somewhat impressed with what you are doing, really. It's just that the image is too deteriorated.

- don

New version with higher res...

http://altoque.tv/35mmAdapter/35mmtestBETA.wmv

Don Berube is right we are loosing a lot of light and considering that still havent installed a dove prism to correct the image. Still, cost vs performace is amazing... DOF is great, my TRV18 is kicking ass with no modifications or aditional investment.

hey Jim, thanks for that credit dude !!

i see that you are having some vibration problems, are you using a cd motor ? did you sanded the cd or was a already frosted one ?

i think they can cut the glass center just like the cd, i saw some stores that have some glass windows with little holes. i will try up with glass next week if i am lucky, i really need to improve this for the comercial version, also i am still working in flipping the image.

agus - I think people would be satisfied in a commercial version if you could find either:

A. an output from the cameras RCA's that will flip the image normal for an external monitor/lcd

B. If you include an LCD that will flip everything.

I like the idea of the prism but I think it will cause too many problems plus it will just be one more thing the light must go through and will bring the light levels down yet again.

I don't think most people have a problem with flipping in post... the problem is to see everything as it is (right side up) while filming.

Agus, are those your sons or your nephews? They seem like good kids. You should name your device after them to reward them for tolerating your chasing them around with your device, which I am sure looks a little scary to them. hehe

Just curious if you could find a way to control the exposure more - so that you are not so overexposed in the white areas of the frame? It would be cool to see a nice flat, balanced exposure.

Is that sound I hear being made by your device? Is there a way you could deaden that sound? Reminds me of an old class at MIT, where the engineering students were given a Braun coffee bean grinder and the goal was to see who could figure out the best way to make the grinder perform as silently as possible. One solution was to deaden the walls of the coffee bean grinder with neoprene and to use a motor which was slightly over-rated for the task of grinding coffee beans. They lowered the voltage to that motor, so that it ran at only the torque needed to grind the beans and it was indeed a bit quieter. I would say that plastic shell of your device is resonating and somewhat amplifying the sound of the motor. Perhaps gluing a thin piece of neoprene inside the walls of your device (or around the motor?) would help mask the sound.

- don

yeah those are my newphies they are twins. :)

The problem really is that the mic of the TRV is less than 3 inches from the motor, so it is silent but the mic is too close. it can be solve using an external mic with no trouble. about the exposure, my bad i was so excited using the device that i didnt set it manually. but well :) i am so haappy that the optics are working well, and the image is not deformed like my first versions, and also there is no vigneting.

Don what do you think about a commercial version ? is flipping the image critical ?

Are you using a fresnel lens or macro between your GG and the camera Agus?

Yeah, a magnifying glass actually it is very powerfull i took it off froma wide conversion lens (VCL-0630 S)

Peter i still havent test using Glass, i am sure i will loose lest light with it than with a plastic cd, also the pentaprism or dove prism should be high quality to work...

I have figured out a static (no moving parts) solution. The test is very promising. I'm still waiting for parts to complete the whole thing. Once complete, I'll have an adapter which:

1. produce upright image
2. smaller (6x10 cm)
3. higher image quality and brighter.

The downside is that the complete cost to produce such adapter will cost a few hundred, might cost more depending on the quality of the coating and glass.

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

<<<-- Originally posted by Peter Sciretta : I think, and I could be the minority but I wouldn't think I am... if it is a loss of quality or light steps flipping the image is not needed if you could somehow see the image right side up while you are shooting (ie flipped on a monitor or lcd).

I would rather that then lose quality. -->>>

peter,
(and others, of course)

i think that there is a place where you can put a prism for inverting!
if the small prism (DOVE PRISM) is mounted as kind of EXPANDER of normal viewfinder (between your eye and a viewfinder) - you will NOT change a picture (quality) at all, you will se everything in a proper way - but you will of course need to flip recorded image after the shooting.
considering small monitor already with the cameras - i think that VERY simple device can be added to commercial version of agus35 - small mirror laying down on one side of "LCD chimney" - so if you are turning your camera monitor bit down - you will look at that mirror which turns everything upside down. so the image foer the viewer will be again proper one.
does this make a sense?

For people who don't use the viewfinder as much as a lcd or crt monitor this viewfinder idea is not good. If you're going to do any handheld work we'll need to see an lcd right side up.

As for the mirror LCD idea, I implimented this with my unit weeks ago... this still has the BIG problem that everything is still flipped horrizontally.

The limiting factor of the current method (mini35) is the requirement of moving the GG. P+S was able to create something fairly small because they probably machined the parts as small as possible. The sole purpose of the rotating/vibrating GG is to reduce the artifacts produced by the coarseness of the GG.

I have been testing a number of solutions, ground glass and other kind of materials to produce a diffusing surface that is very fine, so fine that it appears to be white to the camera. With such surface, you can project image on to it and there won't be any noticeable artifacts. The result is pretty close, but not yet there. I'll let you guys know how it goes.

This is a very rough test of the my static solution. I am still looking for method to improve the quality. Especially in terms of transmitting more light and to be able to "distribute" more light to the corners. Maybe a frensel lens would help.

http://f2.pg.briefcase.yahoo.com/bc/louisfeng@sbcglobal.net/lst?.dir=/35mm+adapter

Hey, I tried to post this yesterday, but I may have found a way to not have to use a spinning CD. I had to scrap the spinning CD because of the size of my camcorder (which made it virtually impossible for me to have a spinning cd). The non moving method has no scratches, dust, etc. The image is bright too.

I used very thin, slightly diffused plastic and if i triple the layers it becomes diffused enough to create the projection. Worked for me. I was using other still pieces and the scratches from the sandpaper were just too noticeable. I knew there had to be an alternative. I'm not sure how it compares to the spinning CD, but it works for me.

Yeah, you need to zoom or magnify it. If you are zoomed in as far as possible, then you need to magnify it before you capture it. I have had problems with the vignetting, but that was due to my holes being off and not totally centered. I was able to zoom in a little more and that fixed the problem...this is just with the lens going straight into the camera without the frosted glass. Haven't got my hands on the sandpaper yet. Hope it works!

Don, that's a good one. Actually I think Agus's last video looks really good. However, it's an outdoor shooting, lighting is much more abundant in that case. I have yet to see anyone that can handle in door lighting well.

It should be noted that the video I shoot was shooting directly from the GG without any cover and was not modified or color corrected in anyway. I'm sure it will look brighter when everything is in a blackbox. But I'm not expecting dramatic improvement from this type of GG (hint, hint).

In fact I am wondering how good the mini35 is, considering there really isn't that much light passing through the lens. I don't believe there is any magic that somehow they can "squeeze" more light from how much there actually is. Again, it probably works well outdoor with bright sun light. I haven't seen any "bright" indoor shots on their web site (most are dark and smoky).

Having played with different kinds of real ground glass, I can tell you that the best/finest ground glass can only produce ok results in a static solution. However, there are other materials can do much better job, both transmitting more light and produce clearer image, but also cost a lot more. Let science do the magic, that's what I'm going to test next. I might even impress myself.

Regarding using ground glass/plastic/consumer products

All the materials above will work fine with a rotating/vibrating solution. The downside is they scatter too much light in every direction. They are not specially made for this video recording.

A static solution is even harder. Ground glass won't work, plastic CD won't work, any short of consumer product won't work. They all produce uneven illumination or visible noise.

I am only considering a static solution for myself, because it would be much more cumbersome to produce an upright image with the rotating/vibrating solution. The missing part right now is to find the best material for the projection. I might have found what I need. I'll know in a few days.