Bob

I'm interested in the static aldu35 type design too. So the bosscreen is not good enough, what about the holographic screens and the Reflexite screens, are there any sources of really fine ones? Has anybody got one and tried spining it?

Now heres another idea for dealing with the grain.

As most of us already know the first models of the P +S Technik used a CD-like rotation GG. Because of picture quality and physical size problems the idea was dropped for a better design where the glass is almost vibrated in place.

But I had a third idea...but its much more complicated movement to build. You can get even closer to a "film look" and deal with the grain issue by having the GG rotate and stop 24 times a second (for DVX100. 60 times a second for other camera). The GG would stop just in time for each frame to be captured. The result would be the same beautiful effect subtle film grain has on footage.

Its kind of imbraces the idea of just a little amount of grain in the picture which might help take that harsh edge off of the image that you find only in video.

Now I know what is involved to make this happen in sync as Im sure some of the techs out there do as well and your right - it would be difficult. I only offer it as a third option for anyone that is interested/cazy enough to try it because its sure to give great results.

-Brett

just in case you didn't check - take a look at upside down monitor solution thread. the inverting/flipping image problem is finally solved! take a look.

filip

Brett.

You don't need to do that. Just set the disk motor speed slow and camcorder shutter high and it's done.

With my DVD-Video version of my Agus35 footage, which is higher res than .avi files, interestingly there is a faint fine scintillation or random grain effect in the image. I dont know whether this is small bright pinpoints being created by the pits in the groundglass. It is like low-light video noise but is finer. These pinpoints might flash fast enough to register sharply in individual frames. It is visible on a hi-res monitor but goes away when projected or viewed on a standard TV screen.

I made mine with an initial pressing of the 600 grade paper against the CD-R disk. Whilst the surface has been subsequently rubbed with aluminium oxide and back-polished, I suspect the bottoms of the pits originally pressed in, remain and have clean sides, with steeper edges perhaps than pits caused by rolling grit in the conventional polishing method.

If you can play back PAL DVD-Video on DVD+R discs, I'll send you a copy by the mail. It might be something worth going after as an effect.

As for rotating the gg in 25 to 30 ps increments, stepper motors and computer controllers might achieve it. There are kits from electronic hobby shops for this. The motion control people in the video/film industry know how this stuff works.

Wayne.

Holographic screens and reflexite are high science things I don't know anything about, so I can't comment on those.

OK, so if the GG vibrates rather than rotates, then the grain visibly disappears because:

- the grain is moving with the frequency much higher than shutter speed, thus creating motion blur in camera;

- the image projected on GG is NOT moving, thus staying sharp for the camera.

My understanding is that the amplitude of the vibration should be small enough to keep GG within the DOF of the camcorder's macro lens, but large enough to create grain motion that would translate into motion blur in camera.

Correct?

Questions:

1. If I shoot with 1/60 shutter always, what should be the frequency of the GG vibration? (I assume over 2 times higher than shutter, eg maybe about 150 HZ?)

2. What small vibrating motors are available? (Ladies' devices are out - size matters in the inverted sense here...)

Anyone who's already experimented with vibrating GG - please pitch in!

A linear movement will not work, unless electronically synced to the camera frame rate so that movement is always occurring when the image is being scanned off the CCD. Otherwise there will be intermittant frames of a staionary gg. The motion has to be circular or orbital if it is to run at a free speed.

The movement, rotation vibration or orbital motion of the gg is across the camcorder's field of view, not back and forth towards and away from the camcorder. Ie., it does not deviate from the focal plane of the objective lens on front or the adjusted relay focus of the camcorder.

I was messing with my Agus 35 today. I just wanted to share with you all that I was very pleased with the images I shot today. No visible grain, no hotspotting and no vignetting. Everything was rock solid. I used all of my 35mm SLR lenses and was able to stop down without increasing vignetting. If I get some time, I'll post some images on my web site. Here's what I used to get my results.

thick acryllic CD spacer ground carefully with 9 micron WAO. (I tried CEO and 5 micron WAO but couldn't get an even enough finish)

Coated double convex rectangular lens, 40mm by 27mm wide by 9.5mm thick at the center. Rounded ends. 63mm focal length
found here http://www.surplusshed.com/pages/item/l1584.html for $3 ea.
The condenser was mounted between the spinning GG and the Video camera, as close to the spinning GG as possible.

I shot with all of the following SLR lenses and had great results with all.
35mm F2.8
45mm F2.0
58mm F1.4
28mm-80mm F3.5 Zoom
80mm-200mm F3.5-F4.0 Zoom

I'm now convinced that the spinning plastic CD is still the way to go for the best image. I'm sure a glass disk will give you better light transmission but how much better? I'm curious to hear how the CD motors hold up spinning the extra weight of glass not to mention the cost. Did I read right? $420 for 10 disks???? I'll post some images asap. Joe

Maybe grinding the acrylic CD very thin would improve light transmission. It's soft and should grind easily. Another CD may be trimmed down to hub size and glued to the ground CD for strength if needed.

Joe.

Yes you read right. It is a ballpark calc. Yes, it is a bit of overcapitalisation for an Agus. I err a bit on the side of technical obsession versus simplicity. Here follows a copy of Hiro's quote :-

""""""""""""""""""""""""""""""""""""""""
I am finally ready to submit my quotation for 10pcs of S-BSL7 D120.0 - 15.0 X 1.2T disks as follows:

1. Glass Type = Ohara S-BSL7 General Optical Properties as per Ohara Catalog Standard

2. Outer Diameter = 120.0 +/-0.2 (mm)

3. Inner Diameter = 15.0 +/-0.2 (mm)

4. Concentricity between OD and ID = 8 micron meter or less

5. Thickness = 1.2mm +0/-0.3 (mm)

6. Surface condition = Ground

Our price for quantity 10pcs is F.O.B. Japan JPY3,400.- / pc F.O.B. stands for "Free on Board".
This means the price includes the cost of the product itself and the cost for clearing customs in Japan.

Therefore the consignee ( customer ) needs to pay international transportation fee. The reason why we offer F.O.B. price is it we have no idea how the consignee wants to transfer the goods ( by ocean-ship, or air-freight, or postal parcel ).
If you have a specific requirement for transportation method, we can quote our price which includes all such costs and you have only to receive the goods at your door.

Please let me know how you want us to ship the goods. Does my explanation help you understand?

Lead-time = 4 weeks after receiving Payment by remittance

End of quote.

"""""""""""""""""""""""""""""""""""""""""

I don't think the true groundglass is going to yield a quantum leap in image sharpness, more like 3% or thereabouts as our images with the plastic disk are already looking good.

Glass will deal with the inconsistent finish when working with the finer grades of polishing compound you mentioned.

That in turn will deal with issues of variable density and flickering.

The CD spindle motors should not have too much bother once they spool up. We are not expecting them to precisely track a fixed rpm with applied power and braking voltages but putting a constant voltage to them and accepting whatever rpm they operate at.

We are also not operating them for continuous long periods as might be expected spinning a CD disk in a player. Provided we are reasonable about the power we put into them they should last the distance.

They may not be as tolerant of violent movements whilst in use, but I suspect the disks, spindles or the motor mounts may fail first.

<<<-- Originally posted by Bob Hart :
Wayne.

Holographic screens and reflexite are high science things I don't know anything about, so I can't comment on those. -->>>

Sorry Bob, I was up all night and must have got a bit confused. Some people are experimenting with ready made holo screens.

I've spent the past week or so reading all of the posts on the Agus & Aldu35, as well as much supplementary info on basic optics theory. The amount of info available in just these two threads is amazing. I've already 'repurposed' an old portable CD player, and started sketching out my design. I have access to a machine shop, so hopefully my first basic design will still be made out of something a little more sturdy than an empty CD-R package. My optical parts should be here soon.

I've decided to go down this path:

Nikon lenses attached to standard mount --> Maxell frosted CD spinning on a portable CD player subassembly --> glass condenser lens (with convex side pointed away from gg) --> an achromatic diopter (if needed, my Sony seems to be able to focus correctly to closer than a half an inch with no help) --> Sony TRV-9 cam with 37mm lens mount

I have the design from the 35mm lens through the gg pretty much finalized, but have a couple of questions after that point. First, the lens mount on the Sony is 37mm. I was planning on just using a step-up ring before attaching to the Agus35. Then keeping the condenser lens at a larger size, so that I can use the same unit with various cams. Does this sound like a good idea? Or would I be better off in keeping the lenses after the gg on a 37mm mount? Will keeping the condenser lens at a 37mm diameter not work because there will still be vignetting? Is there any practical difference as to the amount of light that is lost due to a different lens diameter? I really want to stay away from glue and the like, and would rather have the unit be easy to take apart and modify over time. I also want the system to be as basic and optically efficient as possible. Does anyone have a good source for step up/down rings of various sizes?

I'll be sure to take pictures along the way, as you all have done, and will also throw together a small description of what was decided on, and why.

For the Agus35 I'm working on, a flipped LCD - with image corrected in post - will probably be used, seeing how flipping the image optically is currently too cost and size prohibitive. The Aldu35 will hopefully be corrected optically using a 45 degree first surface mirror and a roofed pentaprism, such as in a SLR (I love the design of that ARRI Digital Viewfinder). Of course this depends on whether or not a suitable pentaprism can be tracked down. Any new leads available?

Joe, could you please post a few photos of your Agus35 as well as the test frames you mentioned? I'm interested in seeing how you mounted that rectangular DCX from Surplus Shed. It's good to hear you're getting such nice results.

I can't wait till I can finally use DoF in my shots. I've never been satisfied with the permanent 'infinite focus' effect built into video.

Ray

Just tested the vibrating GG - successfully!

I simply used the Nikon's focus screen as GG, and attached a micro vibrating motor from old cell phone to the side of the GG's frame.

While GG stands up vertically, the motor is attached horizontally to its side.

As a result, the motor's vibration does not change the GG's distance from the cam's lens, but rather moves GG across the cam's view.

Result: it definitely eliminated all small imperfections which were otherwise highly visible with static GG.

Larger areas where GG's structure is uneven were less affected - due to the fact that the amplitide of the vibration is rather small.

So if GG is quality ground with say 3-5 micron grit, no scratches/blemishes/eneven areas, then my test shows that the vibration will completely eliminate any visible grain.

I'm now cautiously optimistic that a HD QUALITY, wonderfully small home-made adapter is possible.

Because no-one (unless i missed it) produced such adapter, do you guys think we should open a NEW thread for it and call the adapter maybe buzz35 or vibro35?

(It seems custom to call adapter variants by the name of their developers, but alra35 does not sound right to my ear :)

alex,

can you pass us some footage or jpgs?

it sounds very intersting. what kind of motor did you use - from which phone (model/manufaturer etc)?

some times ago i bought for the same reason (someone already mentioned that in thread - the vibrating motor for cellphones) the stand alone vibrating gadget for cell phones, but i do not know how to change pulsating character of it (buzzz-silence-buzzz-silence-buzzz... etc), so maybe your knowledge will help us.
how dificult is this to build?

filip

<<<-- Originally posted by Alex Raskin :
While GG stands up vertically, the motor is attached horizontally to its side.
-->>>

i forgot to ask you about above - can you describe/ draw/picture this in more detail?

thank you

filip

I might have a lead on cell phone and pager vibrator motors if anyone is interested... I believe they are sold in lots of 10

Alex,
I'm curious as to how you are insulating the rest of your adapter housing from the vibrating motor. I experimented for a while with a homemade oscilating motor using rubber bands to suspend the GG/condenser assembly but I could never get the thing to be quiet enough for shooting and the whole box vibrated terribly. If you licked that problem, then you are definately on your way to a compact, high quality adapter. I look forward to hearing about your progress. Joe

PS: Welcome to the addiction Ray,
I will post some pics on my web site soon. I just have to take some snapshots of the Agus 35 and upload it all to my web site. Should be just a few days. You wouldn't happen to know a Sony engineer would you???? ASk around. The answer to the inverted image is in the camera.

Please continue here:

vibro35 adapter (http://www.dvinfo.net/conf/showthread.php?s=&threadid=22456&perpage=15&pagenumber=3)

Its probably a better idea to continue this topic as a new thread on the main Alternative Imaging Methods (http://www.dvinfo.net/conf/forumdisplay.php?s=&forumid=70) forum because a moving ground glass will apply to all upcoming HDV camcorders and not just the HD10.

To reduce vibration, mount the motor and screen assembly on a floating mount, springs, bands or whatever with a low natural vibration period.

There will be a need for lots of compensatory mass to be attached to the motor mount otherwise the motor itself will move instead of the screen. Lots of compensatory mass means extra weight and difficulty keeping the groundglass on the focal plane without vibration and noise being conducted by the guide system to the case.

Unless my recollection is faulty and yes, it often is, Agus Casse initially went this route and changed to the rotary groundglass.

Unless the groundglass can be kept really light, thin and small, the vibrating system may be a design dead-end.

Had an idea for a simple vibralens or vibrafilter. Mount a GG from a 43mm filter to a 52mm (or larger) filter's mount with rubber contact cement. It shoud mount securely, yet still have a little play. Then attach an earphone without the plastic earpiece, and strip the speaker down to the magnet and cord. Then plug the cord into the earphone jack on the camcorder! There should be enough vibration to obscure the grain, but should still run silent.

Hello all,

For anyone interested, you can see some images from my Agus 35 here. Just click on the pic with the Agus 35 rig. There are frame grabs, a test clip and design photos. I look forward to reading your comments. Thanks! Joe

http://www.paddlefilms.com/35mm adapters.htm

You'll have to copy and paste the link to your web browser.

Joe.

Sorry mate. The address you give above either throws up a Google Search page on 35mm adaptors or the following message :-

""""""""""""""""""""""""""""""""""""""
Bad Request

Your browser sent a request that this server could not understand.

The request line contained invalid characters following the protocol string.


Apache/1.3.27 Server at www.paddlefilms.com Port 80

"""""""""""""""""""""""""""""""""""""""""

Just change the space to %20 - try this:

http://www.paddlefilms.com/35mm%20adapters.htm

(urls can't have spaces - they need to have 'url encoded' characters for most anything except letters and numbers)

Sorry all,

I've renamed the page so there shouldn't be any problems now.

http://www.paddlefilms.com/35mmadapters.htm

Let me know what you think, Joe

PS: The corrected link posted above by Jonathon won't work now. Thanks Jonathon for doing that. Can anybody email me how I can be able to post an active link?

Yeah, no problem... just wrap your address in a url tag in open brackets (I can't type it, but it would be... pretend that the parenthesis in the following are square brackets:

(url)http://www.somepage.com(/url)

put the slash in on the last part. This will link the page.

There's more information on these kinds of things at the following:

http://www.dvinfo.net/conf/misc.php?s=&action=bbcode

Joe.

Seen the pics amd they look good. Seems like you've got it sorted. Grain and spots on the disk?

I don't know about the PDX10. I believe it's the PD150's little bro.

I suspect it may have the same offset CCD arrangement as the PD150 as I notice the cropping comes in on the left corners where it appears at all.

At 30 fps, the camcorder may be seeing massive over-exposure and clamping the shutter speed really tight.

This means that stuff on the disk surface is going to be frozen. You'll get it randomly frame-by-frame like film grain and dirt on film and you won't easily see it on monitor playback.

You may not see it on a smart progressive scan TV at all if it is sweetening the image. (That's a rumor, not established fact proven to me).

You may have locked it at 30fps but you may have to use a ND filter in the image path somewhere if there is no other separate also lockable setting for light or gain adjustment available that the camcorder does not automatically compensate for.

ND's will force the camcorder to see low light and lower the shutter speed for a given selected frame rate.

Ideally it should be in the region of 1/60th of a second to get similar motion smear to film though 1/120th or thereabouts has been suggested to me to preserve better apparent resolution.

Slower than that and the PDX10 may do a PD150, halve the frame rate or dump one of the fields which lowers resolution.

I guess the easiest way to fit ND filters will be to make another slot in your condenser lens holder and slide pieces of filter gel into that. Make it thick enough that you can stack them or make an insertion holder like a Bolex or CP16 uses.

Thank you Jonathon for the info on posting live links. I bet there are many regulars here who will find the info useful.


Bob,
You're right. The PD100A is the lil' brother of the PD150. I meant that the PDX10 was the next generation of the PD100A. The PD100A isn't being manufactured or supported by Sony any more.

My camera allows me to adjust both shutter speed and the iris sumultaneously so I don't believe it is automatically adjusting for an over bright image. I can surely over expose the image if I want to. It also has a "push-button" ND filter (can't be optical) which helps cutting down glare and evening out luminosity of the image. I certainly get a sharper image with 60fps. I believe the softer 30fps image is due to motion blur of the spinning disk but I could be wrong. I definately see the motion of the spinning disk at 250fps or higher. At that speed, the image sort of "throbs" giving it a homemade film transfered to video look. It kinda reminds me of old 8mm movies transfered to video. When I get a chance, I'll post some test grabs at various frame rates.

Right now, I'm working on a mirrored hood that will allow me to completely correct the image in my monitor without surgery to the flipout monitor or having to buy a seperate monitor and mount it upside down. It is based on the "roof" of a roof prism. I tested with two rear coated mirrors mounted at 90 degrees to each other. I 'm now ordering optic quality, surface coated mirrors so I can build a proper monitor hood. I'll post pics when It's all ready.

Thanks again for the tips and info,

Joe

http://www.paddlefilms.com/35mmadapters.htm
here's the direct link to the site (thanks again Jonathon)

I have played with a roof array for image erection into camera. For that purpose it has to be huge and totally impractical.

For your purpose I guess it will work and for a practical light box which will not bring your face too close, the mirrors themselves may not have to be too long to get the field of view you need for the LCD screen. You may find the thing getting a bit heavy to handhold that far outboard and possibly vulnerable to transport damage.

If you need it to be shorter, you may find four smaller mirrors as a porro prism array may be easier to manage. You might be able to bring the viewport back over the top of the camcorder but the porro arrangement would be extremely ugly.

On "www.dvinfo.net/media/hart" under "aguserector" you may find some info on my experiments.

hey Bob, i forget to post the solution for the image correction when shooting, i have a lot of work and the oportunity of my life in the door next to me, ( making my first tv show with my own company at one of the mayor tv station in Guatemala, and i am only 21 years old ! ).

So... have ever think of using a roof prism in the viewfinder in the camera ? not the big LCD screen, the little viewfinder, that we barely use cause we love the big screen :)... Well i order a few prisms and i test them with my TRV, (havetn test any of the adaptor stuff with my DVC80 yet.) and they work perfectly.

Heres the link and they are really cheap, i got 5 of them so i could experiment with a few of them.

http://www.surplusshed.com/pages/item/l2080.html

1 thousands thanks for keeping the Agus35 project alive, and hope to start working again in a new version. Thanks a lot Bob

Agus Casse

Agus; Its funny you should bring that up; I just ordered the same item last week and am waiting for it to arrive!

he, he, i already tested it some time ago, and it works.
(shame on me, that i didn't tell you...)

if you are looking for it - just find the cheapest binocular but not with porro prism. the other one - straight one, with that schmidt roof prism. i found one here in poland for 4$ - used one, and bit out of order, but that prism part was not infected, and this works for me. to be honest the picture inside that prism is little bit too small, but it definitelly works. and by conisidence fits perfectly without any glue to rubber eyepiece of my pd100.

filip

Yes! Shame on you for not sharing! ha ha.

I too have ordered the close-out mounted roof prism. I also ordered two other mounted errecting prisms from that site. They should arrive by week's end. I WILL share which of the three work the best.

Is there anyone else holding out on us???? Now's the time to come clean and spill the beans. They say confession is good for the soul. It can't hurt our adapters.

Joe

Her is a link to making your own HD camera, it includes a reference to:

Minolta manufacturers some high
tech GG called lentilinear???, or
something that consists of many
micro sized lenses that make the GG
brighter. They may sell us the
material.

In it's homemade idea.

http://www.cinematography.com/forum2004/index.php?showtopic=434

I have to say, that it should be perfectly possible to make a projection plane that takes the projected image, and projects it directly forward like a laser, or on low angle, or even straight towards the image plane (progressively narrowing the angle as it reaches the centre of the image). Result would be near 100% light. If you asked the optical manufacturers some of their staff should know something, if you searched through the US and EU online patent databses you should be able o find references to all the designs under the relavent section. A image plane of the first sort would just consist of a surface array of microscopic condenser lenses.

CD sized optial glass disks have arrived - nearly. They're in customs.

Preliminary methods for mounting these thin disks for hand dressing/polishing are likely to be to use doublesided adhesive tape cut into small 10mm or 3/8"squares to stick glass to a plane metal surface.

Spacing between adhesive squares to be about 1mm or 1/16" to enable entry of solvent to dissolve adhesive. Whole disk to be dipped and left to enable removal from metal surface without mechanically stressing the disk.

The optiCal people I have been observing have not been polishing glass on glass but using a steel surface to polish the glass against, so I shall try doing the same. this may reduce the scratch problem.

Furthur to above, I got the Ohara disks out of customs hock.

They are light enough that the CD motor won't have any trouble spinning them and they are concentrically true.

The downside is that because they are raw cut disks, I now have to polish the front side to clear transparency. the machine at the optical shop takes about an hour to polish a glass lens.

Unfortunately my disks won't fit within the workspace of that wonderful machine

Based on the number of orbits per second I've got four hours of rubbing ahead of me by the armstrong method.

Impatience has prevailed and I have shot some footage through an optical-grade glass Oharadisk which is as yet hastily and incompletely finished.

I have asked Chris to post some images. These are named "agusgla1.jpg" through to "agusgla7.jpg" with number 5 missing. If they are posted they will be found at www.dvinfo.net/media/hart

The disks come in raw unfinished form and are described as cut disks.

The first one spins up on the CD spindle just fine and runs truer than the plastic spacer CD I have been using.

The front surface of the glass disk which should be shiny I have only yet dressed to what might be best described as a satin finish. The rear groundglass face is still the raw form as received.

I was curious to see whether the unfinished front surface, which is a shiny plane surface with pits in it, whilst partially transparent, might also perform much like an anti-reflective coating to reduce flare from internal reflection within the disk.

The results are of course soft and I did not take meticulous care in setting up the backfocus and focus of the lens itself with the tests which were with the camcorder handheld. I wanted to see how it performed for contrast.

The SLR lens was the CIMKO zoom I used on the music video. For comparison through the unfinished glass disk and a finished plastic CD-R disk, the files "mtatk2f1.jpg", "mtatk2f2.jpg" and mtatk2f4.jpg" can serve as references as these were shot through the same lens.

Update on the glass disk.

So far, contrast and colour is good with nice whites. Resolution comes up in moderately dull lighting conditions - just, to the pressed groundglass/backpolished plastic disk but texture or "grain" is more obtrusive.

In bright light or strong highlights, sharpness falls over and the image bright spots bleed more into surrounding image.

So far I have polished the front face clear and the rear face to 300 grade aluminium oxide opacity. I have to try for a finer finish on the groundglass face, or give the boss-screen method a try with two clear disks.

Anyone knows part number/how to order the Minolta's clear focus screen that supposedly has no grain and no markings?

Strange how people don't seem to want to talk about that in this forum, do you have a link? I asked about something like this recently, as well. What ever the case is, the wavelength of light, should enable a screen to be made with a grain far beyond HD.

I have a number of links to technology they use to control and diffuse light in LCD pannels (3M is a good source). They tightly controll light, and it's direction. What ever we get we want the lght rays from the projection to go straight down to CCD size (like a laser, so no 35mm DOF loss), how to do this is another thing, but most attempts so far try to do this. Maybe a projection screen that shoots straight and then a lense to downsize the straight rays, for 3-10% light loose through the projection system. I haven't got time to sort out the refs on this yet, but it is there for anybody to look at. 3M optical products (I think they are the leaders), the Society of Information Displays (SID) has a list of Manufacturers and products, and I have seen about three new style high gain screens (no they don't produce light, they shine it over a more limited angle), one that can be stuck on plain glass, floating around here.

Thanks

Wayne.

Wayne.

I guess in my case it is what I don't know about I haven't talked about. I did enquire about fibre-optics and there are products which can invert and others which can reduce image size in the sense that I understand you suggest. The advice given me was that the resolution would not come up to our requirements.

My modification of a night vision unit to a PD150 would seem to bear this out. There seems to be a 500 TV line limitation though a new product offers sharper resolution which suggests fibre-optics are getting better.

The 3M material seems like it has to have already an existing planar image immediately against it. Of itself it may not be able to behave like a groundglass screen. One would have to have a piece of it to find out.

The material may confer benefits such as less bleeding of highlights into surrounding image which might be aggravated by the relay lens into the camcorder.

For myself, I have too many committments for me to go down another research path at present before I find this one to be a dead-end if it turns out to be.

Understood, it is only a suggestion for research, as there is still some optical issues with the present scheems. I too have about 8-10K of printed research pages left around here (most not read), and have spent 100's of hours in relation to some specific display/projection subjects (with an earnest desire not to do so again). While one manufacturer might not have the right product, that doesn't mean that another doesn't have a much better version of it. Maybe if I spent another 100 hours I may well find a extremely good projection material, but maybe this Minolta has something real to offer us (have to look it up).

I think there are some optical effects filter products which perform similarly.

The purpose is apparently to confer a soft image with sharp highlights and microlenses is the way it is achieved.

RE: Prism image erector for Agus35.

I have sent an updated conceptual diagram and support note to Chris Hurd in hope he can post it with the others on

www.dvinfo.net/media/hart

There is much more to be done on it and hopefully, someone with superior electronic drafting skills to my own (nearly none) might be able to translate original 2D plans to 3D model. I have tried and failed. The drawings can be provided in .tcw and .dxf formats

So far it seems the most practicable method will be to make the prism array in craftwood. This material has very small particles and remains reasonably stable if not dampened.

The disk motor drive plate will have to be fastened to it or kept in accurate alignment. The whole assembly will have to be movable for either backfocus and final axial alignment purposes.

This could be achieved by having the motor mount plate adjustable with three spring loaded screws or pillar bolts/nuts which would give two directions of angle and one of adjustment parallel to the lens axes.

Separate fixings would have to be used to provide parallel adjustment across the lens axes.

This might be as simple as three spring loaded set screws tapped into the outer case and oversized holes in the mount plate and oversized washers for the mount plate screws to permit a lateral sliding movement.

Provided the initial build accuracy is accurate, this second adjustment method should not be needed but might be sought by builders concerned with precision.

The precision issue is not with the image from the 35mm camera lens onto the groundglass as the 35mm motion picture frame is smaller that the frame the lens was designed to project.

Critical positioning of the disk outer edge and prism edges will already be fixed in the prism mount/disk motor assembly.

This method however is a very significant departure from the original simplicity of the Agus35.

Desirably, the prism/disk motor assembly would be a separate assembly from the rear camcorder lens mount to reduce noise. The CD-R case would cease to be a structural element and become a simple cover for the groundglass disk.

They're posted now, Bob -- thanks,

Thanks Chris.

To all.

RE: DRESSING AND GRINDING DISKS.

I have been scheming and planning for means of
cheaply automating the process. The machine is yet to be completed and the following is all unproven theory.

So far it looks like being a gemstone tumbler style thing :-

1 x washing machine AC pump motor.

1 x automotive engine water pump. - or -
1 x automotive power steer pump.

1 x oversize elastic band or flat drive belt.

1 x 50 disk CD-R case outer cover.

1 x 25 disk CD-R case outer cover.

1 x 25 disk CD-R case inner spindle. (Pillar cut off).

Several scrapped CD-R disks for spacers.

One custom brass donut shaped roller, with deep
concentric grooves cut in it about 2mm (1/16") apart.

1 x door hinge.

3 x pieces of chipboard or scrap ply panel.

Assortment of screws gutter bolts etc..

METHOD:

Water pump or power steer pump is mounted by its
bolt-holes to a wooden panel. A clearance hole may
have to be cut out for the impeller.

The 50 disk CD-R outer is mounted to the pulley with bolts or screws. Use sealer or contact adhesive on the heads to lock them.

The washing machine pump motor is mounted to drive
the water pump or power steer pump with a flat belt straight off the motor shaft like a flat belt turntable. (The plastic pump housing, seal and impeller will have to be removed. The plastic seal retainer may be an integral part of the motor and have to be retained for mounting purposes.)

The timber panel is mounted to a base plate with the door hinge. The third piece of timber is a prop. Another door hinge could be used and nails or screws used to make a ledge for the edge of this to hold the main panel at the correct angle.

The whole thing will look like a small cement mixer.

The CD-R 25 disk outer case will slip inside the 50 disk outer case. They are handily tapered. It needs to be removable as it will wear out. The spindle with its pillar cut off is now a lid.

The spacer disks may have to have the centres cut out and stacked until the centre hub of the CD-R case no longer touches an entire disk and the disk will sit flat and steady. These might best be glued in place. The glass disk sits on top of them.

The brass donut rolls along the face of the glass disk in a polish slurry. The tilt angle has to be adjustable for best pressure versus the disk continuing to roll smoothly. The tilt must also be there to keep the slurry pool inside not on the floor.

My version uses a Ford 6 cylinder automotive water
pump. This yields about 70 rpm with an AC 50hz electric washing machine pump motor driving off a 4mm approx shaft. For 60 Hz motors, the larger power steer pump pulley may be needed to keep the drum speed down. Buick V6 water pumps have a larger pulley but may be more awkward to mount.

All the automotive water pumps are doing is providing a bearing, a pulley and something with bolt holes in it to mount it with.

For the Aldu disks, a much smaller drum, maybe a small plastic food jar with a pressed lid and a smaller donut would be needed. For contact pressure the donut might have to be thicker for weight. In both examples the donut should not cover more than about 5/8th of the disk diameter otherwise the rolling action will become erratic.

The motor and pumps should be found in waste bins at repair shops. Whilst components essential to their function as pumps may have become completely ruined, often the bearings and the electric motor in the case of the washing machine pump remains serviceable. Do not wire the motor up yourself but have a qualified electrician do it for you.

No warranty of satifactory performance is made either express or implied.

Hi All,

Alex here. I have been going tru this site for the past couple of months and with all the info i learnt alot and got down to buidling my very own Agus mini35. I finally sorted out the image inverting problem. I am using the pentaprism from an SLR camera and its 45 degree reflecting mirror. The whole set up is installed close to the ground CD and I just zoom in on the image reflected tru the pentaprism using my MX500 (PV953) DV camera. it worked well when i just place the individual items together by hand. So I have no doubt it works when I fit them all together. Its down to getting the alignment right for the whole set up. Will definitely show you guys the pictures of the set up.

I am actually using 2 nos. of 4 inch white UPVC end caps, four 25mm/6mm dia. nuts and bolt (Stainless Steel preferred), 3mm thick perspex glass cut to shape to hold a small size motor and a 90mm dia. cut CD grounded with a 1000 carbon carbide paper. I am using a 50mm f1.8 lens (Very fast) and a 80-210 f3.8 zoom lens for the canon FD mount. great stuff. everything fitfed properly.

I am having problem with the placement of the pentaprism as its offset alot from my agus 35 setup and it kinda look funny sticking out higher than the agus 35. (I know its hard to understand with words but once I send the pics, you will know what I mean) I am trying to send an autocad file or a jpeg file into this forum. How do I do that?

Anyway, thats all for now. will email some more once I got my pictures safed into the computer. I lost my digital camera cable. So can't download any pic.

Sounds great. Look forward to seeing it. Sounds like you have one of the few compact video cameras that has a lens that can focus and zoom in close enough to see thru the opening of a 35mm pentaprism. Unfortunately this area is too small for most pro-sumer/pro cameras. You lucky bastard ;-) Alright we'll send off thoughs drawings. If you cant seem to be able to post them email them to me at BErskine@mail.com

Good luck with the rest of your design
-Brett

Hi Brett,

Actually, the pentaprism and reflector mirror create a distance between the camera lens and the image on the ground cd. I think the distance is equivalent to roughly 50 to 60mm. I have to infact zoom in 5-6X in order to get a good view. That roughly means placing my camera lens 50-60mm in front of the image. I hope that makes sense. Of course I am not entirely sure but i guess most cameras can focus on something at that distance, if not 2mm distance.

Sure, I am about to finish off the drawing on the proposal and I can send to you.

Alex

Hello!

I just read through the entire thread and is feeling a bit dizzy. Ah well, time to start on the Aldu35 thread then.

But! Why is my first post ever in this thread?
Well, I e-mailed the MOVIEtube people, asking for an approximate price.

Here is the answer:


Hi Christian Loennechen,

the MOVIEtube Pro will cost 14.500 Euros. The estimate price for the MOVIEtube Light is 6.500 Euro.
Thanks for your interest in our product MOVIEtube.

JK-Marketing and Sales-


That is about 18,000$ for a Movietube, and 8,000$ for a Movietube Lite.
Wow! That's a lot of money! Especially if you check out the lite version on their page, it seems pretty simple...

I guess that won't be an alternative. Back to the old plans of making and Agus or Aldu then.

Hi guys,

Finally completed my mini35 adaptor with inverted image. The setup is good but the lighting sucks. Mostly because my MX500 (PV-DV953) sucks in low light. But very good in daylight. Anyway, I can send the images for everyone to see but can someone tell me how to post the image on line. I made the Agus35 version as well. But I am using a small monitor turned upside down to view the inverted video. This version is much better as it allows more light in.

Hi Brett, I can send it to you. I will do that tomorrow as I still have the images in my camera.

By the way, this web page is interesting as it describe how to install and use of the P+S Pro35 adaptor. It even has close up photos of the parts. http://www.dvxuser.com/articles/mini35/

Alex