Mini35 Oscillating Ground Glass Idea
 

Has anybody tried to incorporate an oscillating motor into their homemade mini35's to move the ground glass? I was at an arcade the other day and saw a ticket game called Big Haul that gave me this idea.

Here is a crude depiction (500 Kb animated gif) that demonstrates what I saw... the arm connected to the ground glass and the arm connected to the motor would have to be shorter in length in order to restrict the ground glass from moving so far to each side.

http://www.geocities.com/millertiller12/GG.gif

I have no idea if the 400 series mini35 oscillates the ground glass in this fashion or if this will even work.

Oscillating Ground Glass adapter
 

Dan: Server not found at: http://us.f2.yahoofs.com/bc/40c66bf9_40cb/bc/My+Documents/GG.gif?bfz8oxABWpLLNYwF

But:
I build a working oscillating 35mm adapter. It will works also with a HDTV Cam because you can´t see any grid. (Excuse my bad English) After very long time, test different construction units and constant new calculation, now it works:
First i used the finest GG i found (with no motion the grid must very, very fine!!! See with HDTV but only a little see with a standard cam). Then the GG is mounted on a plate. This plate is fastened at 3 points with spezial rubber bolts, that allowed mouvement only left and right, NOT!! up and down. On this plate is a motor, like a CD-ROM Motor, with a very low imbalance. With power on, the motor, the plate and the GG is oscillating 3 to 5 times more that the very fine grid. (This oscillating makes an very little circle). You can´t see with your eyes that oscillating, but the gid is never see with the camara. The vibration is very small and kill together with any sounds by using another 3point rubber bolts. This last one is also used to adjust the GG distance to the lens. The whole thing is small and very insensitive in relation to outside vibrations or movements.
Possibly I will arrange a self made kit or will sell the complete equipment. See times

Sorry, try this link:

http://www.geocities.com/millertiller12/GG.gif

Rai, I have a HDTV camera I am building can you send me info for the GG you made right away? I want to try it with HDTV

Find something no more than a 1/2 inch long that can hold two mini bearings side by side and I'll post a picture of a design that works just like the Mini35 400 series. Its the only thing I havent been able to find.

-Brett Erskine

Brett,

When you say find something no more than a 1/2 inch long... I assume you mean an arm or an extension right?

Obin: Next week i have some web space and i will upload more information about my adapter.

Brett: Do you know in details like the original adapter works? how large is the oscillation (in mm)? Which frequency? Can you post the picture, becouse I have my own finemechanical and electronic workshop, so everything is possible...

Dan,

You need to make the travel as short as possible and the oscialtions or vibrations as quick as possible. The short travel is necessary becuse it is easier to keep the distance from the lens constant. The quick movement change is needed because you don't want this thing to be staionary at the end positions too long.

I suggest that you attach the motor at the top of the ground glass, not in the middle of the arm. It would also help in keeping the distance to the lens constant. If you need some help with the design, you can email me directly.

Mike

Mike,

It did occur to me to connect the oscillating arm from the spinning motor directly to the ground glass as you mentioned. As in this example:
http://www.geocities.com/millertiller12/OscGG2.gif

Yes. The Mini35 series 400 oscillates a round piece of ground glass in a very tight circular motion. To clarify this is a oscillating motion which is different then spining or rotating the GG. I've seen the system first hand but I dont have exact specs when it comes to measurements but if asked to give a estimate I would say the GG was about 55mm in diameter and the oscillations moved the glass in a circular path no larger than 5mm in diameter. The speed, by eye, wasn't too fast as to create a blur but near to it. For example you wouldnt be able to count the rotations by eye. Of coarse that is at the highest speed setting. The Mini35 is adjustable in speed (more or less apparent grain).

As far as the part I was referring to in a previous post- Yes a arm with one bearing on both sides will work. You will need at least three of these arms all together in order to make a perfect oscillating movement. When I get a chance I'll draw up my design and post it. The design is basic in concept but will need to be made with precision and its important that it finely tuned to be counterweighted as to not add any subtle shake to the footage - let alone noise. Many people may end up making oscillating designs not only for their adapters to be grainless but also because builders of the static version are finding it impractical to keep the GG surface PERFECTLY clean. Because if you dont anything and everything - no matter how small - shows up in your footage.

-Brett Erskine

Hey guys,

Circular motion is the best. I heard that Pro 35 claims to have an elipsoid movement. They have some patent on that unit. The Mini 35 has no patents as far as I know.

A circular motion would mean that there would not be any time when the adapter is stationary. Problem are vibrations and Pro 35 has variable speed mainly to prevent vibrations / oscialtions of the lens.

You could have another identical drive on the top. The two drives would work in mechanical or elecronic sync.

There woiuld be no pivot, just sime kind of sliding mechanism to hold the GG from moving back and forth.

You could also have one drive only, connected to the GG at one end with an arm and you would fix the middle of the arm with a pin and the arm would have a slot about a fraction of an inch long with the pin inside. Then the glass would then make the same circular motion as the pin on the drive.

Mike

thank you Rai

Not the PRO35 or the mini35 are patented, it is the principle which is patented, so every design with a moving groundglass is covered by this patent.

For the german speaking guys between the community I found the patent (you have to search for the patent):
http://de.espacenet.com/
Beschreibung: Videokamera-Einheit
Veröffentlichungsnumme r : DE10164138 A
Veröffentlichungsdatum : 2002-10-24
Erfinder : WEIGEL WOLFGANG (DE)
Anmelder : P & S TECHNIK GMBH (DE)
Aktenzeichen:
(EPIDOS-INPADOC-normiert) DE20011064138 20011230

I also found a description how the PRO35 works, including a very informative graphic, but I actually don't know where I have it, at home or at work.

The oscillating is very minimal, I barely could't see the movement of the groundglass at the Pro35, so I guess it is less than 0,1mm that the groundglass moves.

dietmar

The patent is from 2002. It only covers the Pro 35. There are no patents on the Mini 35. That overall principle is not covered. Because the overall principle is not covered, you have many ways to go without infringing on the Pro 35 patent. P+S cannot patent the overall principle because a product was already introduced that is using this overall principle and is not patented.

Why was not the Mini 35 principle patented? Because it was not patentable; the principle existed in other products already and was not originally patented or the original patent expired.

I wander what does that 2002 patent cover, and if it is even enforcable.

Mike

Don't forget that both Mini35 an Pro35 use a smaller GG that covers the area of 35mm motion picture film, about half of the stills camera. Diffferent issues regarding vibration and DOF and FOV also.

Mike you're absolutely wrong, the patent covers all kind of moving groundglass systems including the mini35, the PRO35 an the Video Director's Finder "VDF-35 / 16", too.

You're telling things you cannot proof, because I think you don't understand German. The Patent is written in german, so I believe you got no Idea what is covered by the patent.

There is something you might not know, when you apply for a patent it is usual that you have to wait about 2 to 4 years until it is published or refused.

dietmar

Dietmar,

Thanks for letting me know. I just noticed that the Mini 35 unit had nowhere any Patent Pend., or Pat. labels, the Pro 35 had them. I wonder what is really patented? Could you be more specific?

Mike

It is correct, i read the patent yet. The patent covers the Idee of all kind of moving groundglass systems (in a adapter for video cameras). Each kind of movement. Rotating, vibration, etc... the Idee of Movement ist the Point, not the way to do that!!!
But:
1.) Many people converted the same idea years before. I enclosed.

2.) For homemade, you can cover everything. You can sell or buy Parts of them. Parts without patents and then you can put it together and you have an fine working adapter.

Watch Out !!!!!!!!!!!!!!!!!!!!!!!!!!
 

That changes things. So everyone should be careful and don't offer to make these for someone else. If you refer to these adapters, refer to them as projects for another purpose. When someone starts making parts for these and what eceryone will be doing with these parts is nobody's business. The patent is from the year 2002. It will be good for a long time. I have no clue for how many years a patent is valid. Seven? Fourteen? It should be however noted that there are many patents that are worthless and will not stand in a courtroom. Also I believe that the company needs to apply for patent registration within a year in other countries. So if the patent is registered in Germany and USA, and not in Mexico, someone can make a million dollar business in Mexico making these. If you drive there from L.A. and buy one, it is a different situation tan trying to make them yourself. Another point is that they may not have US registration. I did patent search here and there was no P+S registration, but I may not have been too thorough. Someone should attempt to do that and maybe some patent attorney can advise in case they are registered. Can someone describe details of that patent? No patents are foolproof and you can always get around them. This is 100% legal.

Mike

Guys,

This amy be a sneaky way of putting us on a notice that the principle is patented. But it does not talk about US patents. Any attorneys on this board? If you start answering in this thread you may legally admit that you are aware of a potential patent infringement. So those who make their own adapters should not read this thread and if someone asks, you should not know anything.

Mike

<<<-- Originally posted by Dietmar Zonewicz : Not the PRO35 or the mini35 are patented, it is the principle which is patented, so every design with a moving groundglass is covered by this patent.

-->>>

I was intrigued by this having read the patent. The patent is very specific about the type of motion covering

a) axis of rotation perpendicular to the center of the image plane

b) axis of rotation perpendicular to an offest outside the image plane (bad news for rotating CD afficionado's)

c) axis of rotation perpendicular to an eccentricly moving point in the image plane - type a) motion with a vibrating axis

d) linear motion in the image plane


Most surprising of all is that pendulum movement is not covered - tick tock motion - just like my German Grandmother clock

PS - frequency must be 100Hz or greater to avoid a stationary GG frame

Well, it would be nice to find out if they have US patent. You can't do pendlum at 100 Hz. How about patents in Asia?

John,
I come from Germany and i read this german patent exactly. The motion you indicated are called in the patent as possible examples (to show witch directions, only side by side). In the paragraph of "patent claims" they call it only motion, without specification. I think this means: all kind of movement.

A pendulum movement has a disadvantage: There are 2 points of no motion, that means the grid is at this points visible.

Hi Rai

The fact that 4 specific motions are referred to without the caveat 'such as but not restricted to' is a weakness in the drafting of the patent and would not necessarily be deemed to cover all motion

An unequivacable way of expressing all motion would have been a single diagram showing rotation and linear motion arrows in all directions - a 'catch all' for the general case

Mike - oops my bad (half period should equal shutter speed) thus should be 25Hz

the 25 hz frequency was based on the Pal frame rate at 50i - in other words - although it is static at 2 points - it is still on average in motion over the 1/50 th of a second timeslice, so the GG would still be blurred.

handheld vibrating groundglass
 

well I for one only want this piece of vibrating ground glass .
to hold in my hand to look up at the sun . If someone later decides to attach it to a camera thats there business . lets keep working on " hand held vibrating groundglass" thank you rai
and hope when I look at your design for "handheld vibrating groundglass" that It will suit my needs for looking at the sun.
and in no way used as a camera attachment to attach at "the focal plane" reebok has a patent on a air pump in a sneaker not on an air pump.


rotating axis ground glass circa 1955


http://www.oldchristmaslights.com/color_wheels.htm

parts
 

Hi everyone
I found this site which may be of help with parts.
If anyone knows a site that sells parts could you give us a link. ---- thanks

http://www.budgetrobotics.com/shop/index.php?shop=1&cart=96359&cat=111&

Richard, thats right. I have made a web side with exact details and pictures. And i can help with working parts, but i will change the web side, so it is for a vibration proportioning filter or something similar, but not for a camcorder attachment (because: see your posting from 16th). The exact formulation (what can i say, what not) will this time examine a attorney. Therefore, please still wait a little time.

Another question: I looking for a reseller so that our parts can be dispatched from the USA

I'm thinking of providing a parts kit for the micro circular movement system also. I have a good source for the mini ball bearings and motors here in Los Angeles. I have the usual machine shop equipment to make the offset eccentric drive for the motion.
I'm going to sell it as a 'mini paint shaker' or something. ;) You provide the substrate in the middle, whatever it may be.
-Les

project
 

they both sound like great names .
looking forward to this project.
-thanks guys

I saw this device in an electronics shop: It has a high frequency oscillating mechanism based on some solenoids?! It was very quiet:
http://www1.jaycar.com.au/productVie...Max=&SUBCATID=

They don't seem to have a fluid optical filter covered. (Some text here was deleted by myself until some tech patent details are checked.)

Just wondering why you guys aren't figuring out exactly how P+S Technik moves their ground glass...The design plans have already been posted you know. No tape, no glue, no wood and they dont even use bubble gum to put their together. There is a difference between cheap and inexpensive.

Answer: why using office supplies to make things
 

There is a post on how p+S puts it together.
The reason most people are not going that route is that they don't have the machine tools to do so.
I do.
This weekend, I will be assembling something to wiggle a small substrate myself. It will use 9 ball bearings in it's construction, and be made of AL.
I may make a kit of this available to others to experiment with.
-Les




<<<-- Originally posted by Brett Erskine : Just wondering why you guys aren't figuring out exactly how P+S Technik moves their ground glass...The design plans have already been posted you know. No tape, no glue, no wood and they dont even use bubble gum to put their together. There is a difference between cheap and inexpensive. -->>>

Les, you know how the original adapter work. I also know it. We build those one, and some different models. One is more quietly than the original, but with the same optical features, and we have the better GG. Also, i found ways to go around the patent and will have own patents. I think we should talk together, and maybe... we can work together? Let´s email

Hey guys I am working on an idea as well but all this patent stuff is freaking me out. I would like to build a rig that I could sell but I would also like the idea to be free to everyone. I have a way to work around the PS patent as well but I am not sure Rai and I have the same thought. Either way if my idea is different I would like a way to make sure it never gets patented and anyone can use it if they want. I am also a little wary about just announcing it for fear some one else tries to patent it. Does anyone no how these patent laws work, is there a way to give an original idea free license?

How to make a quiet, smooth oscillating mechanism
 

Make sure your movement is extrememly small to avoid excessive vibration of the camera itself. You only want to make the GG move. Anything more and your might have vibrations show up in your footage because you camera itself is shaking. This will also help in reducing sound problems.

Here are some other things that will help produce a oscillating mechanism thats not only quiet but only vibrates the GG and not the camera.

1)Make whatever is oscillating (the GG and mechanism) balanced as perfectly as possible and as LIGHT WEIGHT as possible.

2)To make it alot quieter use large rubber O-rings instead of gears to move your mechanism.

3)Mount anything that moves or makes noise on rubber mounts to contain not only sound but vibration

4)Use a housing that is completely enclosed and perhaps even insulated.

5)Always use tiny bearings on moving parts v.s. bushings

6)Find a small electric motor thats runs quiet and smoothly at a speed thats works for the gg, noise, and vibration problems.

Good luck guys.
-Brett Erskine
www.CinematographerReels.com

One possible source for small bearings, motors, etc, would be a hobby store (r/c car parts)

update
 

I worked on the prototype of my 'mini-shaker' and it is about 80% complete. It moves a substrate in about a 1 mm radius. The alignment of the bearings is pretty critical, and I will have to remake one of the parts to get it moving a bit smoother. It's constructed mostly of Aluminum,stainless steel, Nylon , Lexan and 9 micro ball bearings. No office or kitchen supplies used ;)
I'll post pics of the core tomorrow.

Les.

Are you rotating a hollow eccentric around a fixed center carrying the GG? This is the most compact way to go but would need to have more than five mini-ballbearings, more like about fifty. Method for this would be two snug fitting races the outer eccentric ring driven by a belt, the inner ring + gg retained from spinning by another fixed belt = less noisy and wear-prone than a linkrod or sliding keyway and pin. The broader crescent portion of the eccentric ring might have to be drilled to bring the balance back to the mass of the GG and its own ring, or maybe some lead mass added into drillholes if you use hard aluminium alloy.

To centre the loading on a single row bearing there would have to be two drive belts, one each side of the bearing row and the third fixed belt might have to be doubled for loading balance too. Skewing the two fixed belts equally would assist to stabilise the gg assembly.

It would be simpler to home-build on a hobby lathe and superior to P+S Teckniks' published mechanism but more prone to wear and contamination from belt particles which is probably why they didn't go there.

Roller wheel drives are fine but are a mongrel to keep correctly set up and compensate for wear without introducing too much friction unless you use a third relay roller like an older style turntable which regulates its own pressure with a spring arm.

I did the three offset shaft type. I don't think the belt will shed too much, I am looking for a nice silicon belt, they last a long time and are sticky as well.
-Les