Les-
Looks like we are both working in the exact same direction. I'm going with a belt and off set shaft system as well. I found a single pulley wheel that houses everything for one shaft. Im using two micro bearings (each just a few mm in size) and a wheel that has pre drilled holes for the two bearings to drop into. The wheel also has a notch along the outer edge for a pulley to set into. I was looking for something ready made because at such a small scale all of the parts that are duplicates have to be EXACTLY the same. If you drill or make your own ...they better be carbon copies otherwise your going to have a loud or rough running mechanism. For thoughs interested I found the micro sized bearings and the pulley wheel at a hobby store. Sounds like you are using a shaft instead that is off set and then you've attached bearings to it. That should work well. In fact your design opens yourself up to having a tighter oscillation radius. Mine is a bit larger - about the sized of a dime. Where did you find thoughs shafts?

-Brett Erskine
www.CinematographerReels.com

Brett,
I made the eccentric shafts on my lathe. I'm guessing on the radius, I think the diameter of the motion is about 3mm now that I look at it in motion. I'm still only turning it by hand, I'm wondering if I will have to do any special vibration isolation. I made the part that moves from lexan to keep it light.
You are right about the precision needed to make this work, I did the drilling of both support plates at the same time to keep good alignment. I'm going to work on it a bit more tonight, to tune it up a bit. I'll try it with my HDV camera in a few days.
-Les

Les and Brett,
tighter oszillation produce also small (outside) vibration. A good GG need only small oszillation. It looks you working in the same direction like P+S (The original is also not 100% loudless. If you hold it in your hands, without lenses, you feel the vibration. It need the mass of lenses+camera to reduce the vibration!).

We had also tray this way. Here our details (it´s 99,5% like the original).

http://de.geocities.com/raiorz/vibro_old/vibro1.jpg

Next days you will found more details and also a different and more simply way...

to Rai

rai, exellent drawings. this is something i missed when i recently looked at p+s shematics. now i understand how it works.

exellent job.

can you just explain me how the platform with GG is mounted not to move in anoter directions (closer/further) but just to turn in excentric circles.

thank you

filip

Filip,
our ball bearings are all firmly pressed in (But also you can hold it with springs, clasp or simply bonded), so the GG platform can not move clother or further. The only play is in the bearings. It is far under 1/100mm. But (if you want, and we found there is no need) you can place little magnets on the still platform and on the GG platform, so the magnetic power pulls the platform always to itself.

To Rai and other Oscillating Designers
 

Rai-
Buddy you are DEAD on! Thats a perfect example of how to make a smooth, professional oscillator. Our designs are so similar its scary right down the where and how its counter weighted. I looked everywhere for off set shafts that are ready made but couldnt find them (at least not that small). You have to make me some of those. If anyone else has a idea of where you can get some let me know. I may have to have them computer lathed. My set up makes it oscillate alittle too wide.

Im on the hunt for a ultra quiet motor. What do you plan on using? Im hoping to find a tiny 7.2v DC motor so that I can just use another camera battery to run it. It would be nice to know what the RPMs of the P+S Technik motor but my guess is at around 1000rpm we shouldnt have any problem. Early on in this project people were using motors out of CD players but reported that they didnt spin quite as fast as they needed to. Then again back then people werent using quality GG or focusing screens so maybe it will be fast enough now. A CD player motor runs at 500rpm. Going alot faster will insure that you wont see the grain but you have to remember the faster the motor the noiser it generally is and you dont want to pic up the sound of the motor in your on camera mics. 1000rpms sounds like a good ball park because we are oscillating the GG instead of spining it. But the best solution would be to have a variable speed controler on a motor that can go alot faster than that. Why? Sometimes we shoot at 1/500sec shutter speeds instead of 1/48th. This quick shutter speed is sure to catch the imperfections on the glass if it isnt oscillating fast enough.

I wouldnt change anything on your design ;-) Everything looks good. I could only recomend that you add a few things that you havent shown yet. Make the mount the motor and the oscillating mechanism on the same plate and when it comes time to house everything in a project box have the everything inside attach to the project box by mounts that have rubber bushings. This is the best place for them. I noticed that you are using rubber bushings where the bearings sit. This is a good idea because you made your own off set shafts but if you switch to some that are precision made (all exactly the same) I would loose the rubber bushings because they cause a little slack in a system that doesnt need it at that point. It some speeds it might actually create strange vibrations if you have the bushings there. You want thoughs three points to be solid.

Lastly if you havent already made it you might find it alittle easier to build if you have 4 off set shafts instead of three. Its easier to find something ready made with 4 holes pre drilled equally apart than 3 holes in a triangle. But more importantly you can make your over all design smaller then. The reason is the off set shafts dont have to be set so far out from the ground glass in order for the O ring to clear it. This is even more aparent if you plan on using a rectangle shaped focusing screen instead of round GG. Personally Im going to go with a Beattie Intenscreen or a Minolta Acute Matte focusing screen. These screens are anywhere from 1 to 4 stops brighter than anything else out there and our adapters need all the light they can get. They do however use fresnels to focus the light instead of a optical lens but Im starting to get real tired of buying a bunch of different plano convex lenses trying to do the same job. As many of us know the optical quality of fresnels arent as good as a plain lens BUT these Minolta and Beattie screens use a much finer etched fresnel lens then others out there. You cant see it. They are perfectly calibrated to give you a even field without any hot spots as well. They are extremely light weight which is a must if you plan on oscillating it. Lastly the microscopic fresnel rings act to contain light that would otherwise diffuse alot more with traditional GG. The result is a sharper image with more contrast. On top of that you can increase most of these advantages if you use a medium format focusing screen instead of a 35mm screen. Grain gets smaller and image gets sharper and has more contrast by at least a factor of 4X. Now this is all true if you plan on using medium format lenses but you can also use 35mm lenses with at least some of the benifits mentioned. You cant use a 35mm sized focusing screen anyways on a oscillating style adapter because the focusing screen needs to be a bit larger than the target area of the lens because its oscillating. You can also get alot of them pre mounted in a frame. Perfect for attaching to your off set shaft.

Alright I better stop there and save the rest for later otherwise people wont want to read all of this info because the post is too long. Anyways Rai since we are working in the exact same direction we really have to work together on this. Email me and/or post info on parts and I'll do the same.

Brett Erskine
BErskine@mail.com

P.S. What camera are you using? I've got a source for $10 DVX100 battery docking mounts to power the motor.

Funny, the drawing looks like what I built!
Form follows function!

I just got some GG, so I can finish it all this weekend.
I may use 4 shafts next time, because it's hard to get the GG size
to fit with the 3 shaft setup.

I'll post a pic of what I have tonight. It's all shiny still, but I'll matte black it as I finalize the machine work.

You can test the Z axis motion by looking at a reflection of the GG plane. It should be without warpage or image shift if it's perfect. Look at it at a 45 degree reflection. It's an easy way to test it out. The spinning CD people had a problem with the Z axis going in and out ruining the focus.
-Les

A few pics
 

Here is where I am at with my 'substrate shaker' .
http://home.earthlink.net/~lesd/hd/

Still needs a bit more work, like mounting the motor, preloading the bearings with springs or magnets, and milling out a hole in the lexan. I'm still thinking of where I want to put the counter weights, maybe in the pulleys. I hand held the motor and it drives it nicely. The whole thing fits in a PVC pipe coupling with the motor outside.
-Les

Les-
You werent kidding. Join the club. Very nice work btw. Could you post a picture of your off set arm and tell us where you found it or how you made it. Also hows that motor working out for you? Is it quiet enough? Whats it's RPM's? Voltage?

I was thinking about the counter weight issue some more and you could also put it on the far side of the shaft. The opposite side than where Rai put his. That way when you add more or less weight its not only easiler but you arent changing the position of the GG. Either way will work though.

I remember someone mentioning the magnet idea before (maybe it was you). You may not need that if you switch to a micro sized bearing because the slack in those things are a fraction of 1 mm. Hobby store. 5 bucks a pop though. Let keep working and sharing ideas. Thanks.

-Brett Erskine

Brett.

Deceased video-cassette players might warrant investigation as a possible quiet longlife motor source. My understanding is that the drum motors are designed to slave to 60hz for US or 50hz PAL country. This may mean 1800rpm or 1500rpm if slaved to their reference.

They have to be powerful enough to drag a half drum past half-inch tape and for accelleration and retardation sharp enough to match the sync signal off the tape against a reference. Best of all, they have a miniature ball-bearing set, an inbuilt balanced flywheel and a nice thick robust precise shaft. They are a bit big and heavy however.

Earlier specimens used a separate high speed DC motor capable of more modest acceration and retardation which was made responsive and powerful enough by a high reduction ratio belt drive to the drum which was effectively an idler or contained a less powerful motor which contributed the final more precise accelleration and retardation needed. These drive motors may not be robust enough and more likely to have been the cause of the appliance failing.

Another source might be the mirror motors from fixed window - bench type supermarket checkout scanners.

Bob, Brett, Les, and all the others in this club...,

Look for (batterie) audio cassette player motors. Most work with 3 to 5 Volt and, with a pair of eletronic parts (poti, transistor), you can speed change simple on power change.

No, why would I be kidding. Oh, thats right, this is the internet ;)
Anyways, as I mentioned before, I used a lathe to make the offset shaft. I was going to use a pin in the end of the shaft, but it's harder to do it that way. Without a lathe, I'd do a pin and put it in with some red locktite.
The motor is from a tape deck, it seems good, maybe a bit big. I'll have to see how fast it needs to run to motion blur out the grain. With a smaller radius the rpm has to be more to get the velocity. The closer you get the weights to the plane of the moving part, the less vibrations you will have. You have to think dynamic balance, CG is not the only thing involved, for this thing, any counterweight will help, it doesn't vibrate that much.
Is yours constructed yet?
-Les



<<<-- Originally posted by Brett Erskine : Les-
You werent kidding. Join the club. Very nice work btw. Could you post a picture of your off set arm and tell us where you found it or how you made it. Also hows that motor working out for you? Is it quiet enough? Whats it's RPM's? Voltage?

I was thinking about the counter weight issue some more and you could also put it on the far side of the shaft. The opposite side than where Rai put his. That way when you add more or less weight its not only easiler but you arent changing the position of the GG. Either way will work though.

I remember someone mentioning the magnet idea before (maybe it was you). You may not need that if you switch to a micro sized bearing because the slack in those things are a fraction of 1 mm. Hobby store. 5 bucks a pop though. Let keep working and sharing ideas. Thanks.

-Brett Erskine -->>>

Audio cassette (Walkman) motors huh...Hmm interesting. I wonder how cheap and small they make AC/DC converters these days that would be to run one of thoughs 48X CD-ROM drive motors or a variable speed. Or perhaps a manufacture has the same motor available in a DC.

My mechanism is half built. I'll post something when I get closer.

-Brett Erskine
www.CinematographerReels.com

you should try ultrasonic motor. that is what they use in autofocus lens like the canon EOS.
see http://www.photoscene.com/sw/tour/inside.htm
you can even see that this kind of motor is like a ring, so stacking two of them can give the ideal movement if they are not centered.
the first one is moving the second which is moving the GG, each one having different speed and are non centered so you obtain a kind of chaotic orbital movement
they run smoother and quieter than regular motor and offer a better torque/size ratio so you probably can have a real small (flat) one. you even can find linear motor that move along a straight line and can go back and forth at more that 100x/sec.
the only drawback is ultrasonic vibration can sometime be a trouble in fine mechanics.
The positive fact is it could help to keep your gg clean...
check too http://www.adaptronics.com/products/ultrasonic_motors/index.html
For instance i am pretty happy with my fixed gged condenser.
with good light, the grain in SD video is not really noticeable.
i learn from several test that a lens with relative aperture at 1.4 is a real plus. at 1.7 or 1.8 you still get vignetting too easily.
fortunately, this is just the kind of old lense with M42 mount you can find for cheap everywhere (mine is a revuenon paid 20$).
Unfortunately you are limited to FL at 50 or 55, because it seems unusual to find a FL under or over with such specs. anyhow 50 or 55 mm is still a pretty workable value, close to what you get from a video camera.
i solve the vignetting effect by using a lens that look like a huge contact lens. This totallly remove vigneting.. you find these lens into any photo or video lense , usually just behind the firste one.

Ultrasonic Motors
 

Giroud-
Excellent idea! Of coarse the ones used in EOS lenses are practical for a few reasons but I'll do some hunting around for a small DC ultrasonic motor. I think ultrasonics may be the answer guys. Thanks

-Brett Erskine

I mean, "NOT practical"

I wonder what voltage the cannon motors need? 50 or 100 volt driver at some high frequency ? I like the look of them !
-Les

They are nearly the diameter of the lens - making them too large to use for our purpose. It would be nice IF they moved in a oscillating motion because we could just simply mount the GG in the center of one of them. But they only rotate and slowly at that.

On another note - Im killing myself here looking for a tiny offset shaft. Can someone pleeeease help me?

-Brett Erskine

Brett, you´r right. They only rotate... so you have a point in the middle with visible grid... and also it rotate slowly...

Find a company with repair parts for audio recorder and you find a lot of different motors, belt, etc., all for small $.

Tiny offset shaft? How much may they cost? How much may a complete set of parts cost? With or without motor, housing, etc.. Give me an idea. Maybe you have found a source...

brett, i love the opening shot on your demo reel...how did you get that look? it's high production value looking!

Shafts, Ultrasonic and demo reel
 

Thanks for the comment on my demo reel. I dont want to talk off subject too long so I'll make this quick.

Shot on 16mm, Two 2k fresnel bounced into 2 3'X3' foam core, dark smoke colored backdrop, fake snow, 1 girlfriend, 45 fps, heavily overexposed, color shift during telecine, slight highlight glow ala Photoshop.

Half of that demo was shot on the DVX100 and the other two "travel epics" demos were COMPLETELY shot on the DVX100. Amazing camera.

For thoughs interested heres a link to the demos:

www.CinematographerReels.com

-Brett Erskine

Back to the subject - I decided to just take to finely threaded metric bolts and have them spot welded side by side at the tip. Its seems like its going to work well because I can just screw on all of the hardware I need on to it and everything will be rock solid. I'll post pics soon if someone is interested.

Thanks for the info about the audio motors. I may end up going that way but before I do I really want to look into these ultrasonics. I found some small ones but they are AC or only 250 rpm. Havent found any advertised prices...Im starting to think that these little guys are expensive. Anyone else doing research on them?

Parts Kit interest?
 

I'm thinking of building a run of parts kits for the oscillating substrate mover. It would be similar looking to the one I posted pictures of before, but with 4 shafts. It would include the motor and mount for the motor. It will be matte black. You provide your own center piece to orbit. The mount will have a hole for it.

It took me about 6+ hours of work to make the first one, but if I do several at the same time, it would make it easier.
I'm thinking $375 for the 4 shaft version, if I get several people interested.
I'm just putting a 'feeler' out there at this time, to see if it's at all interesting to those DOF fans out there.

-Les

Les-
What city are you from? I'm from Anahiem, CA. Maybe we should work together on our adapters.

-Brett Erskine

I suppose I'm gonna have to read this thread more carefully to really understand how this device rotates/oscillates/does-its-thing.
Les,
I'm wondering what modifications might need to take place to use a Medium Format lens, which projects an image twice as large as a 35mm lens projects onto the GG. Major Reworking of the design, or just cut a bigger hole and space it all farther out?

Matthew, these pictures shows the basic device I made:
( see the dsc named pics )
http://home.earthlink.net/~lesd/hd/

I do plan on making the next one bigger and with 4 shafts to allow more optimum use of the middle area. Using a larger area even with a 35mm derived lens would be a plus.

-Les

what motor?
 

i was in the hobby shop last friday, and discovered very powerfull (and expencive - about 200$ (at least in poland) ) brushless motor with all cabling etc. - for remote controled model airplanes, cars etc. which can acheive more than 20.000 rpm. and is very quiet. does anyone of you know more about these things?

motor is in my opinion proper in size and if you use lower voltage - it revolves slower. (it starts from 750rpm and each 1v added is 750rpm more)

i understand that for our purpose - we will need minimum 1800 rpm (ntsc) or 1500 rpm for pal countries. yes?

does anyone knows what manufacturer made p+s motor?

================
to les dit:

i'm impressed! great work! what kind of motor you are using with your device?


thanks,

filip

Re: what motor?
 

Thanks!
I used a motor from a tape recorder.
The motors from the hobby shop you mentioned are high amperage high power for cars and planes. The motor I use only draws about 1/3 amp at 6V , you don't need much power.
The speed depends on the shutter speed as well as the radius of movement.
-Les



<<<-- Originally posted by Filip Kovcin : i was in the hobby shop last friday, and discovered very powerfull (and expencive - about 200$ (at least in poland) ) brushless motor with all cabling etc. - for remote controled model airplanes, cars etc. which can acheive more than 20.000 rpm. and is very quiet. does anyone of you know more about these things?

motor is in my opinion proper in size and if you use lower voltage - it revolves slower. (it starts from 750rpm and each 1v added is 750rpm more)

i understand that for our purpose - we will need minimum 1800 rpm (ntsc) or 1500 rpm for pal countries. yes?

does anyone knows what manufacturer made p+s motor?

================
to les dit:

i'm impressed! great work! what kind of motor you are using with your device?


thanks,

filip -->>>

Im going with medium format GG because its at least 4X as large (surface area). Contrast, sharpness are greatly increased and grain reduced. I plan on using medium format lenses once in a while but the beauty of having over sized GG is that you can choose between different format lenses. Want to use a 35mm lens - fine, a medium format lens - fine too. Thru test I found that 35mm lens already throw a image nearly the size of 2 1/4 medium format GG so this means even if you stick with 35mm lenses you'll see a fairly large improvement in contrast, sharpness and grain. ANOTHER plus to using medium format GG is you dont have to zoom in as much with your camcorder's lens and you know what that means...You can use a faster f stop on your camcorders lens which is VERY important for a homemade mini35. AND since you dont have to zoom in any more that also means that you dont need to use expensive achromatic diopters.

Im having a custom GG made by a specialist. He really seems to know what he's doing and he claims its the brightest, least grain, most even field GG out there. Well see. I'll let you all know.

So Les how do you like the tape recorder motors? Are you picking up their noise in your mics? Are they fast enough to get rid of the grain...even at 1/500 shutter speed? Are you going to keep them for your next version of the adapter or would you change anything about them if you could?

See ya
-Brett Erskine

one more thing
 

I should mention one BAD thing about using larger (medium fomat) GG. Chances are you'll end up with a adapter that is a hair too large and heavy to safely screw mount to the video cameras lens without the aid of a rod support system. Just something to keep in mind when building.

-Brett Erskine

Brett: Your idea sounds excellent! However, if you do decide to switch down from medium format to 35mm lenses, you would need to use an achromat and/or zoom, right? (Due to the smaller projected image.) Or did I miss something?

Thanks!

frankly whatever is the size or weigth or your adapter, i would not recommend using it without some support , without the risk of seeing the front of your camera popping out .
additionally using the upside down camera is a good idea that require some additional mount anyway.
if i got time i will show you some pics of my aluminium mount, it is ugly but very efficient.

I agree with Giroud,
The screw mounts on camcorders are very weak, usual held together with plastic components.
If you are serious about going to the effort of mimicking 35mm DOF, you should be thinking of a rail mount system for the DOF maker and the filter holder as well as shade system on the front of that.
Be careful of that little screw mount !

-Les

Frank-
To answer your question...Yes AND No. All 35mm lens project a image larger than a 35mm focusing screen (36mm X 24mm) BUT how much bigger is the question. I hear that they are all slightly different. The lens I happen to check was a Canon 50mm F1.8 (or f1.4 I dont remember). That particular lens projected a image that nearly filled the entire GG measuring 2 1/4 inches square. If I had to eye ball it I would say the image was 2-3 times larger than a 35mm focuing screen.

What does it all mean? Well if that image size is aprox right for just about all 35mm lenses then you should be able to shoot without any achromat lens (at least with the DVX100. I havent tested other cameras)

As far as a rod support system - Im with you guys. Most cameras only have a 2 or 3 threads in the front of their built in lens. The first time you bump your adapter hard on something...well I wouldnt want to be you. You likely to watch your adapter and film lens fall to the floor and break - only to find later that thoughs 3 threads that are a perminate part of your video camera are also broken. You may never be able to thread ANYTHING on front of your camera again. No thanks.

Which brings me to my next question. Can I see pictures of your rail system Giroud?

-Brett Erskine

A furthur affirmation of a support system for the mount. Close coupling still imposes a load on front of the camera even if the lens hood mount is used.

There is quite a lot of compliance in the lightweight camera body and it is not good to exercise that too much.

ok , first pictures.
http://www.giroud.com/miniDV/frame1.jpg
http://www.giroud.com/miniDV/frame2.jpg
http://www.giroud.com/miniDV/frame3.jpg
http://www.giroud.com/miniDV/frame4.jpg
probably a good pass with a black paint spay will help to get a more professional look
not seen on picture is the hires LCD monitor from sony, allowing to make sure that focus is ok. It will be fixed just behind the cam in a way you can tilt it a bit .
All is made from very cheap aluminium profile. You just need to cut and assemble together. The full stuff cost me less than 35$.
tubes are 16mm diameter, but unfortunately i do not respect the standard distance between them (should be 80mm) to be compatible with professional devices. not too bad as i do not plan to mount expensive professional item on it anyway.
the lense as a front thread of 55mm and i found an adapter to 58mm so i can mount my wide angle (canon WD58 or my anamorphic wide lens -century optics)
if i got time, tomorrow i 'll put some shot from the camera.

today i was to a photographer shop to see some lenses.
I compare several 50mm 1:1.4 from minolta, pentax, canon, nikon.
Despite having the same optical specs, all these lenses were really different when comparing the diameter of the lense.
there is at least 5 or 6 mm in difference in diameter between the smallest and the biggest lens.
That means you can get a 50mm 1:1.4 lense that has a rear lens of 30mm of diameter when an other lens can have 36mm of diameter. this makes probably a huge difference regarding hotspot and vignetting.
i am starting a 2nd prototype with oscillating gg.
I think you can easily solve the problem of excentric shaft.
you drill a plate and insert the axis into the hole. you just need few mm to get the roller bearing to plug on it.
then you make your Delrin parts twice as high as the roller bearing. in the first half you will put the axis centered. the second half will be drilled to make a hole to cover the roller bearing.
the trick is to drill that hole slightly out of center. that is easy, probably even more than drilling it centered.
an other way would be to drill the second axis out of center, with as better result that the delrin part turn centered.
all the stuff should not exceed few milimeter high.
i thing the delrin part should have a big diameter so you can outcenter the 2nd axis heavily. the result will be that even a slow rotation will induce a big translation. that requires a bigger glass but should cause less vibration.

Giroud ,
In the USA , if you took that outside, I'll bet the police would be there soon, thinking it's a weapon of some kind !

Nice work on the AL parts, it all looks pretty clean!

-Les

just a thought...

has anyone tried an optical image stabiliser mechanism from say a busted camera to move the GG

by-pass the sensors and feed it a sinusoidal signal in x and y to produce the orbital motion

OIS supports a lens element so a GG would be that much lighter

also they are small, light, quiet and designed to fit in a tube

support system
 

thank you giroud for the pictures of your support system .
It looks very professional.

this will be of great help in helping all of us to make our own .
I have a 6 pound anamorphic lens I would like to use. your rack system will let me use it


this is a link to a company that sells aluminum rods I can't
vouch for this company yet but they seem to have parts we might need . http://www.smallparts.com/

Thanks for the link. Im sure I'll be able to find some things there. I checked out their supply of aluminum stock and unfortunately they dont deal with metric sizes. I mention it because support rails and most pro accessories are based off a 15mm rod. FilmTools have them for $70, which even I think is too expensive for something so basic. They are however chome plated and you can screw in extensions.

Any more sources guys?

Also Les I never heard what you thought of the audio tape motors. I would love to hear some responses to the question I posted the other day.

Thanks everyone.

-Brett Erskine

motors
 

Bret,
I think I mentioned that my motor was from a tape deck, so yes, they seem to work fine. They usually have a little pulley on them as well, so you don't have to hunt for that also.

I haven't had time to finish my shaker rig in the past few days, I have another opto-electronic project that is going to eat most of my time in the next 2 months. Gotta pay the bills! I'll try to get it all mounted during this weekend.

-Les