Totally Home-Made Oscillating Mechanism

[Sarena Valilis]

ok.. finally going to build a similar unit , but i have a question..

what is the Minimun rpm that has worked???

does anyone know???

[Justine Haupt]

Wow! What a great thread! I never new this existed until today... and good thing -- I'm about to start constructing my adapter and seeing this I decided to revise my GG support... (I'd planned on using 4 oscillation points, but three seems obviously better).

Although, it seems to me that by using such a small rotation diameter on the oscillator mechanism (<1mm) and by using a belt drive to turn them, the mechanisms in this post are really more vibrating GGs than oscillators. What I mean is, it was said that it's necessary to use as small a rotation diameter as possible, but this shouldn't be necessary if all three rotation points were always synchronized, as a true oscillator would be...

I was going to try using a larger 2-3mm rotation radius with counterweights and a timing belt to keep sync... my thinking being that a smoother, faster and quieter oscillation could be achieved this way, but the key is definately in the synching, and either a chain or a timing belt were the only things I could think of to do it.

Does anyone think that's worth it, or should I just go with the tiny diameter everyone else is using?

[Rok Furman]

just wonderin... why don't you rotate the GG? like the experimant with the ground up CD :) it shouldn't transfer any oscillations to the camera body, neither should it produce any audible noise.
i'm thinking gyroscopic issues, am I right? or is it just because you don't like excess bulk?

BTW, i don't want to start a new topic, so i'll just ask here. does anybody know of a website where the actual working of a 35mm adapter is shown?
i'm kinda thinking of experimenting a bit and building my own - and i don't know what should happen behind the GG. you see, i would mount it to an XL1 and i just don't know how to get the picture to the CCDs. i was thinking of mounting a prime (set to wide open) to the camera so that it gets the picture from the GG to the CCDs (macro), but i don't have a clue what to do to mirror the image back to it's correct state. an elaborate set of mirrors or prisms maybe?

[Ben Winter]

but i don't have a clue what to do to mirror the image back to it's correct state. an elaborate set of mirrors or prisms maybe?

There are a few people around these boards working on a mirror system, however the common method is to rotate the image 180 degrees in post--this allows the maximum image quality to be retained, if adding some hassle to the post production process.

[Rok Furman]

nah, no hassle... it's just not simple to shoot with the image upside down in the viewfinder - if only you could rotate it in the viewfinder somehow.

you could use a field monitor though... and rotate it 180° :)

does anybody know how this is achieved in the actual P+S mini35?

[Ben Winter]

From what I understand the P+S adapters all use a mirror system to flip the image to its correct position--hence why they're so expensive. For adapters without that nifty component, you can use an upside-down LCD screen to view the image, or, use the "magnet trick" to trick the LCD into thinking it's been turned around so it'll flip the image upside-down for you.

[Marcus Marchesseault]

I got my LCD monitor finally and I immediately took it apart. I removed the touch-screen glass since it degrades the image and I don't need that feature. I also removed the now-useless USB cable to save clutter and weight. To top it off, I put the LCD panel back in upside-down so now it is perfect for use with a 35mm camera adapter. I think the threads on the bottom are perfect for use with an israeli arm or some other hotshoe adapter. Not bad for under $200 and an hour of labor. The only thing I am missing is s-video, but at least I have true 640x480.

The monitor I got is the VM80 from short-circuit.com. Their customer support was excellent after I informed them that the V7000 they carry does not have s-video and can't display 4:3 properly.

[Justine Haupt]

Originally Posted by Rok Furman

just wonderin... why don't you rotate the GG? like the experimant with the ground up CD :) it shouldn't transfer any oscillations to the camera body, neither should it produce any audible noise.
i'm thinking gyroscopic issues, am I right? or is it just because you don't like excess bulk?

For me it's mainly bulk, but I'd also like to control the amount of grain in the image with a speed control, wich can't be done with a a spinner. A round GG also seems like it would be a much bigger hassle to work with... what If it needs to be changed? The size needs to be right and a hole would need to be drilled in it just to get it prepped... nah, an oscillating mechanism might be more complex, but I think it's definately better.

BTW, i don't want to start a new topic, so i'll just ask here. does anybody know of a website where the actual working of a 35mm adapter is shown?
i'm kinda thinking of experimenting a bit and building my own - and i don't know what should happen behind the GG. you see, i would mount it to an XL1 and i just don't know how to get the picture to the CCDs. i was thinking of mounting a prime (set to wide open) to the camera so that it gets the picture from the GG to the CCDs (macro), but i don't have a clue what to do to mirror the image back to it's correct state. an elaborate set of mirrors or prisms maybe?

I don't know of a website (which is crazy, because everyone who wants to make one of these has to kind of infer the required knowledge from the forum... it's a great forum, but a simple drawing for people just getting into it would be great)... that said, I decided I'm going to put a complete description of 35mm adapters, how they work and why one might want one on my website when I finish (or at least when I'm far enough along) with my adapter... along with, yes, the construction plans! It's been taking along time just to design the thing, which is a large part of the effort of making your own... a month now and I still find myself making a major revisions to the drawings (for example, I was deciding on how to handle an adjustment for the flange focal length and decided to go with an adjustable bellows mounted directly to the GG support plate. I should also say though that I'm keeping aesthetics in mind, so it won't be a cube with a lens sticking out of it. Some people might not care so much about that, but I think that's at least a little important.

As for what happens between the GG and the CCDs on the XL1, there should be a relay lens or two (there's a great lens system design program called Synopsys available here http://www.osdoptics.com/ free for 90 days -- it's a great program and lets you do everything graphically, but the learning curve is a little steep)... but a macro should work, too, I'm just wondering if you'd be able to get the frame big enough in the lens to eliminate the edges.

As for image flipping, I've decided to go with a mirror array to do it. I don't want to have to mess with flipping an LCD or anything like that, and I really don't see what people are afraid of in making mirror flippers... no, that's not true, you have to be careful of light loss, alignment, etc... but it's really not that bad. I have the flipper portion of my project worked out and all the measurements are ready to go (it did take longer than expected to design... but that's why I'm going to publish all this stuff for others to use). You'll get a flip and a 180 degree turn around when two mirrors are angled at 90 degrees (45 + 45), so do that twice and you have a flip on both axes and the light's still going in the right direction. From the lens' point of view, pitcure a mirror that's angled 45 degrees to your left, which creates a 90 degree reflection into another mirror that's to the left of the first mirror and angled up 45 degrees, which in turn reflects up into another mirror that's angled down at 45 degrees, so the the image is reflected back to the right, which reflects into a mirror directly above the first mirror, and that mirror's facing away from you and angled at 45 degrees from the third mirror to reflect a final flipped image in the same direction, and offset upward as far as mirrors #2 and #3 are apart. A porro prism will do the same thing, but I think the light loss is significant. Someone posted a picture of their mirror flipper a few weeks ago, which probably says it alot better than I just did. There's a great book on optics "Optics and Optical Instruments" by BK Johnson from Dover Publishing that has just about anything you need to know.

Ok, just trying to help... please post pics when you have somthing going so we can see!

[Wayne Kinney]

Originally Posted by Justin Haupt

I'd also like to control the amount of grain in the image with a speed control, wich can't be done with a a spinner.

The SG35 has a speed control, and its a spinner

[Justine Haupt]

Oop, I stand corrected. I don't mean to knock spinners in any way, but isn't it that the disk has to always be spinning fast enough to eliminate all the grain? One reason for my preference of oscillators is that the amount of grain could be controlled to the extent that, if say, I want a certain amount of grain across the entire frame, I could slow it down enough to achieve that, whereas it was my understanding that a disk couldn't have grain-amount-control as a function of speed because a spinning circle is not moving at a uniform speed. Of course, I realize many (or most... or almost all) people might not care at all about intentionally letting the grain show, so a spinner is fine, but I really am trying to save every bit of space I can, too. With the mirrors, bellows and relay lens on the adapter, coupled with the Angenieux lens and matte box I eventually want to get on there, my camera stands to be absurdly large... and not in a good way. I want to be able to shoot from a car, at least, so I've been going crazy making this an efficient design.

[Gev Babit]

Finally got back to working on the adapter after 2 years and completed it a few months ago. I shot a couple of projects with the dvx-100a and they came out great, I'm very happy with the results. I have not tried it with HD yet but that is the next step. Here are some pictures of my rig, follow focus, rails, adapter and some footage.

http://www.papalico.com/PB351.jpg
http://www.papalico.com/PB352.jpg

http://www.papalico.com/Chills.mov
http://www.papalico.com/Movie_Royale.mov
http://www.papalico.com/Star_98.7.mov

[Rene Hinojosa]

Nice piece of work! What were the total costs associated with your adapter? The footage looks clea, very nice. Congrats!

[Gev Babit]

Thanks Rene.
The follow focus and rod system cost about $100. The adapter cost about $1000 including all the experiment optical parts, I tried many different ground glass and achromats until I found something I liked. I made a fast shoulder mount for the rig for about $25 in a day which the fight scene was shot with.

http://www.papalico.com/pb35sm.jpg

[David Delaney]

Where did you buy the rod system?

[Gev Babit]

Everything except for the camera and tripod I built.