Rotating 35mm Adapter - Someone Show Me How To Build This??

I

Ill Eagle

Well-known member
I have an optical path that looks pretty damn impressive but I want to switch to a moving GG and I'm not too fond of the spinning disc or ground glass (Micro35) and vibrating is way out of my DIY capabilities.

I think everybody has their own "Look" they want from 35mm Adapters and I really have found the optical path that is the "Look" I like but.......grain issues. I was going to try to build this but with my optical path.........

PB050176.JPG


Anybody have any insight on this adapter and what parts are required to make it?
 
i always assumed you'd have a point in the center of the ground glass that looked strange if you spun it like that. the outside would spin fine, but there might be a small static point in the center.

anyone know?
 
It's an offset spinning setup, so the center is not constant, but moves about 1mm off-axis throughout the rotation.

I've seen that adapter and have the diagram of the design, but it is big, loud, and requires a good bit of power. I'm not sure if it disturbs the cam with its vibrations or not, but I know the manufacture of something like this takes a certain amount of exacting work with the tolerances and the results are... well, not too many people are making them, that's for sure.
 
Hi,
The photo above is actually a photo of Nick Bartleet's adapter ( http://www.pixelloft.com/ ). It does infact have a constant centre since the GG spins inside the large bearing, so I have always thought the same as luster about the static centre point, but check out Nick's music video's on his site, they also play alot on MTV and there does not seem to be an issue with grain.
 
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"It does infact have a constant centre since the GG spins inside the large bearing"


Hi Wayne,

If this was shot on the adapter in the photo, I'm going to build one this week sometime. That MV looked amazing!
 
Any interest in plans / parts for a rotating mechanism?

Any interest in plans / parts for a rotating mechanism?

There are quite a few designs on the forums, but no really clear plans and most good designs require at least one precision machined part.

I'm thinking about putting together a version of the design with three spindles (one is the motor shaft, two are independent). Each spindle has an offset section in the middle -- sort of like a cam shaft. The spindles are mounted between two rings using small bearings. A third inner ring (containing the ground glass / focus screen) is sandwiched between these rings and mounted with bearings to the middle offset section of the spindles. An offset of a half mm or so would give a total excursion of 1mm or so. The bearing mounts allow the inner plate to move in an elliptical fashion about the X and Y axes while maintaining proper orientation of the frame, with no movement in the Z axis. The motor is fairly low speed.

Has anyone built one of these? I'd love to hear your experiences. If I put it together and it works well, I'll post plans, pictures, etc. I'd like to get into a 52mm Thorlabs tube if possible, so people can add the mechanism to their existing static adapters.

Anyone interested? If so, let me know what you'd like to see.

Thanks,
Steve
 
Yeah, I got the picture of one of your posts, Wayne from Dvinfo and I downloaded Nicholas Bartleet's video's and this is THE ADAPTER I have been aching for. The look is perfect. I liked the Guerilla35 but it didn't give enough 'Width' for me and I liked the 'Width' of the Micro35 but couldn't stand the look.

This adapter has the perfect look I am trying to achieve and best of all, it isn't static. Could someone help me build this or atleast give me a breakdown of parts?

I am also surprised their is no consumer-friendly commercial version of this design........
 
Here's a rough drawing of the mechanism I'm thinking about building. It's based on a combination of several other mechanism found on the web. There are also a number of laboratory chemical shakers with a similar design. Has anyone ever built one with this design?

I'm hoping to fit it into a 52mm Thorlabs or PVC tube.

Note that:
* The middle plate should move in an elliptical pattern about the X and Y axes, with no movement on the Z axes.
* The plate should maintain it's X and Y orientation.
* The ground glass / focus screen is attached to the middle plate.
* The middle plate bearings attach to the eccentric portions of the shafts.
* The gray rectangle in the middle is the motor, the dashed rectangle opposite it is the battery mount.
* The gray rectangles on the sides are spacers with a screw on each end.
* I can probably get away with using only one end plate.
* I'm not much of a mechanical drawer!

Remember, I haven't built this yet, so I don't even know if it works.

mechanism1.png
 
tigeba said:
Width?
Click to expand...

I can't really explain it. I like how 'Wide' the field of view is on the Micro35 but I don't like the look. I like the DOF on the Guerilla35 but it's too shallow at times, even when used with different lenses, the field of view seems small to me. This adapter seems to provide both which is the look I'm going for.

I already have a battey holder, the project box, lens mount and Medium Density Fabric (Foam?).

Can someone help me with finding a site/place that sells small motors, pulleys and large bearings with holes in the center? That picture doesn't give a lot of info........

Anyone??
 
There is a post where the builder of that bearing 35mm adapter explained it all. Ill find it later, but basically he said it is a large industrial bearing, with a center at least big enough for lets say a 40mm 50mm? i dont know. Then a circle shaped Ground glass is glued into the inside of the most inside bearing ring. then he also bought a nylon circle pulley that was small enough to glue to the inside ring of the bearing. So that way, when the pulley is turned, it is spinning the inside ring of the bearing, in which the gg is attached. a rubber band or whatever drvies the nylon pully. put in a case and your done. perhaps youll need a condenser and such also.
 
Ill Eagle said:
I can't really explain it. I like how 'Wide' the field of view is on the Micro35 but I don't like the look. I like the DOF on the Guerilla35 but it's too shallow at times, even when used with different lenses, the field of view seems small to me. This adapter seems to provide both which is the look I'm going for.

I already have a battey holder, the project box, lens mount and Medium Density Fabric (Foam?).

Can someone help me with finding a site/place that sells small motors, pulleys and large bearings with holes in the center? That picture doesn't give a lot of info........

Anyone??
Click to expand...

I still don't understand your "width" term, but as for your question:

http://smallparts.com

http://www.goldmine-elec.com/
 
Forrest Schultz said:
There is a post where the builder of that bearing 35mm adapter explained it all. Ill find it later, but basically he said it is a large industrial bearing, with a center at least big enough for lets say a 40mm 50mm? i dont know. Then a circle shaped Ground glass is glued into the inside of the most inside bearing ring. then he also bought a nylon circle pulley that was small enough to glue to the inside ring of the bearing. So that way, when the pulley is turned, it is spinning the inside ring of the bearing, in which the gg is attached. a rubber band or whatever drvies the nylon pully. put in a case and your done. perhaps youll need a condenser and such also.
Click to expand...

Thanks, yeah I studied the hell out of his threads regarding the adapter. I think I got the method and construction down (I think) it's just parts that I'm not sure which to use and where to find them.........

Thanks bklyndv, for the site. As far as 'Width.' I mean like the DOF and FOV. I like how wide the FOV is on the Micro35 and I like the DOF on the Guerilla35. But the Micro35 has a wierd look to it that still seems somewhat video-ish to me. I like the look the Guerilla35 gives off but I haven't seen any samples that made me like how 'Wide' you could get a shot and have a deeper DOF, not that I've liked, it's a personal taste and this model adapter seems to give off the look I'm looking for as every 35mm Adapter has a unique 'Look' it gives off.............
 
The width (field of view) is down to the focal length of the lens they used. You may get a little more FOV depending on the image size but most adapters are around 24x36mm image area, which is what the lenses are designed for, larger and you start getting a hotspot.

The depth of field you get is down to the lens focal length and aperture but is also influenced by the GG, which is something I discovered in my own experimenting, not sure people reaslise how much influence it has. If you have a coarse GG you get more light loss and more grain potentially (won't be a problem on a spinner) but better bokeh and the depth of field is actually shallower. If you have a finely ground GG you have better light loss and generally less grain, but the depth of field will appear deeper from the same lens at the same aperture compared to the coarser more diffusing GG, not to mention the hazy look you get on out of focus stuff with finely ground GG's.

An adapter like the G35 has a lot of diffusion hence shallower depth of field compared to something like the MPIC, which is better for light loss and sharpness of image but at the "expense" of having deeper dof. Depends what you're after as to which you prefer.

Nick Bartleet's adapter produces some of the best results I've seen but it's not exactly going to be a run and gun thing when you consider the weight of one of those bearings.
 
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I also looked into this type of adapter and scoured the web for bearings suppliers. I will see if I can post some links to bearings suppliers.
 
ASG is right -- FOV is totally dependent on the lens and the imaging size, which should properly be 36x24mm. It has nothing (or should) to do with the adapter.
 
I understand that a lot of it has to do with the Lens, what I'm saying is every adapter has it's own look and I like the look the adapter gives off. Look at the footage from all the different adapters, they don't all give off the same image and bokeh.........

I just happen to like this adapter and am trying to build it. I have a grain free and it's static, so I want to put that optical path in this adapter. I have found the motor thanks to bklyndv. I just don't have the bearing.........
 
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