Mini35 Oscillating Ground Glass Idea

[Martin Lindstedt]

I've just built myself a prototype, and I fear that the motor will have big problem putting the three shafts in motion. What's the big secret of having the shafts running as smooth as possible? ..

This brings me to my to next question .. For those of you who got a working model: Are you able to turn just one shaft by hand, when the GG plate is on?? I was able to do this with my prototype .. One reason for this could be the fact that I used plexiglas instead of aluminium .. or because the holes for the bearings wasn't perfectly aligned .. or maybe my shafts needs to be more off-centered ( today they're 1mm off )

Another thing that struck me a while ago.. Isn't there a chance that the three shafts will go out of sync? Especiallly if you move the GG plate in a small radius? .. Any help appriciated!

[Dogus Aslan]

martin can u show us photos of your prototype....

if you think about..you are making a plate that is held by two eccentric shafts...for the system to run perfectly the shafts have to mimic the same motion...if one shaft of the two is not paralel..or impositioned..its impossible to get the plate to turn...when you have 3 shafts you have more importance..

how did you cut out the holes for the shafts?

"This brings me to my to next question .. For those of you who got a working model: Are you able to turn just one shaft by hand, when the GG plate is on?? I was able to do this with my prototype .. One reason for this could be the fact that I used plexiglas instead of aluminium .. or because the holes for the bearings wasn't perfectly aligned .. or maybe my shafts needs to be more off-centered ( today they're 1mm off )"

..can you eplain what you ment...

good to see new people in :)

[Martin Lindstedt]

Hey Dogus!

Yeah, that's true .. the holes needs to be perfectly aligned .. For my next try, I will drill the holes on all three plates at the same time, thus making sure that they are aligned .. I didn't do this on my prototype .. so .. shame on me .. :)

Btw, I saw your pictures on your model! It's looking really good!

Well, I just wonder what happends when your turn one shaft by hand, when the belt and GG plate is on? Do the two other shafts start to move as well in the same direction?

[Dogus Aslan]

yes when i turn one shaft the other shafts turn..the reason for this is in the way the parts are been built...

take a look ..

www.us.trumpf.com/31.tc3030-4030-6030.html

i have done my designs on cad programs and i got them cut out on this thing...it is 1/100 mm accurate (hundrath of a millimeter)..in my design i have two plates holding the shaft ...so the shafts have no escape but to stay inline!

[Dario Corno]

Sorry for the OT.


Dogus : I work for PrimaIndustrie :D

http://www.primaindustrie.com/

[Dogus Aslan]

hey Dario! u r the man:)

i need to ask u 2 things..

1- whats OT?
2- for the ground glass we all have been trying to get..i was wondering if a laser so delicate could create marks on the glass..with very small distances..so we could have a very fine ground glass?

[Aaron Shaw]

I think people found that when you get too fine the glass starts to reflect light. That's just a faint memory though.

OT = Off Topic :)

[Brett Erskine]

Cannon has laser etched GG in at least one of their Pro cameras these days. Last time I checked none of the optional screens were without markings so - unuseable. They are incredibly fine grained though. Better than even Satin Snow Glass. Perhaps if you talk to the right people at Canon you can find out who makes them for them and have a plain one done. I tried getting them on the phone but couldnt find anyone who could get me specifics. But if you have someone else make one tell them that you need a "random" grain structure done because normally lasers are so acurate that they will produce a extremely fine pattern and you dont want a perfect pattern. It can have a moire effect with the cameras CCD.

-Brett Erskine.

[Dario Corno]

<<<-- Originally posted by Dogus Aslan : hey Dario! u r the man:)

i need to ask u 2 things..

2- for the ground glass we all have been trying to get..i was wondering if a laser so delicate could create marks on the glass..with very small distances..so we could have a very fine ground glass? -->>>

No, the main problem is not the radius of the laser beam, but the heat it will generate. The way (I believe someone is doing it already) is to use waterjet machines. They trow an high pressure water jet, mixed with abrasive diamond sand on surfaces, usually to cut them but it's also possible just to mark 'em.
I believe buying a big glass plate and marking all the surface then cutting it with the same job whould cost really really less than buying pre-made ground glass.
Let's say with the price you'll spend for a single groundglass you can mark and buy and cut something like 1x1 meter plate.

I will contact Finnpower or Waterjet (two of the most famous waterjet machine producers) and ask them.

I saw in a show here in Italy machines cutting optic glass (that's always due to temperature, water cuts at ambient temperature).

I'll let you know.

[James Hurd]

Progress anyone??

http://www.sunrushmusic.com/micro35/micro35test.htm

[Les Dit]

Hi,
I haven't been following the thread for a while, so I'd like to know if any of the other efforts besides mine have generated sample footage ?

How about those parts that were cut on a very expensive laser machine the size of a small house.... got footage yet?

-Les

[Dogus Aslan]

hi les...i think the small house design ur talking about is my small house:)

i have got good results..but the design had a problem when running it too long the glass layer part tended to lose position making part of the projected image blurry...

i have brought the design to a master in micro mechanics and design, and we have agreed to take the design from the begining..only this time better!....the presicion is very high..i am hoping alot will like the overall product..

i want to publish pictures from my new design, but this will take a few weeks...it is going to be interesting, there arent even any bearings in the design!

[Les Dit]

Oh OK,
I know from my experience that if the shaft alignments are not perfect, the glass holder will want to walk away from the shafts as it all moves. My second attempt at the shafts fixed that problem. I still had a very slight image vibration in my HD demo, however.
I also have an idea that does not use standard bearings at all. I've just got too many projects on the list right now!
-Les

[Bob Hart]

Les.

I don't know how it goes for NTSC and 24P over there but with the simpler numbers in PAL country of 50 / 25P, you may find that if you shoot interlaced, then apply the motion signature recipe which has been published on this site, the vibration may go away although you may get a much slower weaving effect somewhat like a worn projector gate with film.

I most recently encountered a similar thing with my AGUS setup when I tried to mount the combination to a very firm tripod. An out-of-balance condition of the disk did not make itself apparent when the combination was hand-held or on light MiniDV tripods but with the big Miller, the vibration instead transferred to the camcorder body just enough to move the image on the CCD about one TV line.

[Dan Diaconu]

Hi Guys,
Here is my last attempt (of 23) to solve the GG movement.

http://pictures.care2.com/view/2/941356005

http://pictures.care2.com/view/1/682555803

Please consider the size (24/36mm ! ) small power requirements,
variable speed and variable amplitude of movement, noise, weight,...... and if you
have an idea of how it could be improved, let me know please.

Regards,
Dan D