Homemade 35mm Adapter

[Joe Holt]

Alex,
I'm curious as to how you are insulating the rest of your adapter housing from the vibrating motor. I experimented for a while with a homemade oscilating motor using rubber bands to suspend the GG/condenser assembly but I could never get the thing to be quiet enough for shooting and the whole box vibrated terribly. If you licked that problem, then you are definately on your way to a compact, high quality adapter. I look forward to hearing about your progress. Joe

PS: Welcome to the addiction Ray,
I will post some pics on my web site soon. I just have to take some snapshots of the Agus 35 and upload it all to my web site. Should be just a few days. You wouldn't happen to know a Sony engineer would you???? ASk around. The answer to the inverted image is in the camera.

[Alex Raskin]

Please continue here:

vibro35 adapter

[Nicholi Brossia]

Its probably a better idea to continue this topic as a new thread on the main Alternative Imaging Methods forum because a moving ground glass will apply to all upcoming HDV camcorders and not just the HD10.

[Bob Hart]

To reduce vibration, mount the motor and screen assembly on a floating mount, springs, bands or whatever with a low natural vibration period.

There will be a need for lots of compensatory mass to be attached to the motor mount otherwise the motor itself will move instead of the screen. Lots of compensatory mass means extra weight and difficulty keeping the groundglass on the focal plane without vibration and noise being conducted by the guide system to the case.

Unless my recollection is faulty and yes, it often is, Agus Casse initially went this route and changed to the rotary groundglass.

Unless the groundglass can be kept really light, thin and small, the vibrating system may be a design dead-end.

[Jim Gauthier]

Had an idea for a simple vibralens or vibrafilter. Mount a GG from a 43mm filter to a 52mm (or larger) filter's mount with rubber contact cement. It shoud mount securely, yet still have a little play. Then attach an earphone without the plastic earpiece, and strip the speaker down to the magnet and cord. Then plug the cord into the earphone jack on the camcorder! There should be enough vibration to obscure the grain, but should still run silent.

[Joe Holt]

Hello all,

For anyone interested, you can see some images from my Agus 35 here. Just click on the pic with the Agus 35 rig. There are frame grabs, a test clip and design photos. I look forward to reading your comments. Thanks! Joe

http://www.paddlefilms.com/35mm adapters.htm

You'll have to copy and paste the link to your web browser.

[Bob Hart]

Joe.

Sorry mate. The address you give above either throws up a Google Search page on 35mm adaptors or the following message :-

""""""""""""""""""""""""""""""""""""""
Bad Request

Your browser sent a request that this server could not understand.

The request line contained invalid characters following the protocol string.


Apache/1.3.27 Server at www.paddlefilms.com Port 80

"""""""""""""""""""""""""""""""""""""""""

[Jonathon Wilson]

Just change the space to %20 - try this:

http://www.paddlefilms.com/35mm%20adapters.htm

(urls can't have spaces - they need to have 'url encoded' characters for most anything except letters and numbers)

[Joe Holt]

Sorry all,

I've renamed the page so there shouldn't be any problems now.

http://www.paddlefilms.com/35mmadapters.htm

Let me know what you think, Joe

PS: The corrected link posted above by Jonathon won't work now. Thanks Jonathon for doing that. Can anybody email me how I can be able to post an active link?

[Jonathon Wilson]

Yeah, no problem... just wrap your address in a url tag in open brackets (I can't type it, but it would be... pretend that the parenthesis in the following are square brackets:

(url)http://www.somepage.com(/url)

put the slash in on the last part. This will link the page.

There's more information on these kinds of things at the following:

http://www.dvinfo.net/conf/misc.php?action=bbcode

[Bob Hart]

Joe.

Seen the pics amd they look good. Seems like you've got it sorted. Grain and spots on the disk?

I don't know about the PDX10. I believe it's the PD150's little bro.

I suspect it may have the same offset CCD arrangement as the PD150 as I notice the cropping comes in on the left corners where it appears at all.

At 30 fps, the camcorder may be seeing massive over-exposure and clamping the shutter speed really tight.

This means that stuff on the disk surface is going to be frozen. You'll get it randomly frame-by-frame like film grain and dirt on film and you won't easily see it on monitor playback.

You may not see it on a smart progressive scan TV at all if it is sweetening the image. (That's a rumor, not established fact proven to me).

You may have locked it at 30fps but you may have to use a ND filter in the image path somewhere if there is no other separate also lockable setting for light or gain adjustment available that the camcorder does not automatically compensate for.

ND's will force the camcorder to see low light and lower the shutter speed for a given selected frame rate.

Ideally it should be in the region of 1/60th of a second to get similar motion smear to film though 1/120th or thereabouts has been suggested to me to preserve better apparent resolution.

Slower than that and the PDX10 may do a PD150, halve the frame rate or dump one of the fields which lowers resolution.

I guess the easiest way to fit ND filters will be to make another slot in your condenser lens holder and slide pieces of filter gel into that. Make it thick enough that you can stack them or make an insertion holder like a Bolex or CP16 uses.

[Joe Holt]

Thank you Jonathon for the info on posting live links. I bet there are many regulars here who will find the info useful.


Bob,
You're right. The PD100A is the lil' brother of the PD150. I meant that the PDX10 was the next generation of the PD100A. The PD100A isn't being manufactured or supported by Sony any more.

My camera allows me to adjust both shutter speed and the iris sumultaneously so I don't believe it is automatically adjusting for an over bright image. I can surely over expose the image if I want to. It also has a "push-button" ND filter (can't be optical) which helps cutting down glare and evening out luminosity of the image. I certainly get a sharper image with 60fps. I believe the softer 30fps image is due to motion blur of the spinning disk but I could be wrong. I definately see the motion of the spinning disk at 250fps or higher. At that speed, the image sort of "throbs" giving it a homemade film transfered to video look. It kinda reminds me of old 8mm movies transfered to video. When I get a chance, I'll post some test grabs at various frame rates.

Right now, I'm working on a mirrored hood that will allow me to completely correct the image in my monitor without surgery to the flipout monitor or having to buy a seperate monitor and mount it upside down. It is based on the "roof" of a roof prism. I tested with two rear coated mirrors mounted at 90 degrees to each other. I 'm now ordering optic quality, surface coated mirrors so I can build a proper monitor hood. I'll post pics when It's all ready.

Thanks again for the tips and info,

Joe

http://www.paddlefilms.com/35mmadapters.htm
here's the direct link to the site (thanks again Jonathon)

[Bob Hart]

I have played with a roof array for image erection into camera. For that purpose it has to be huge and totally impractical.

For your purpose I guess it will work and for a practical light box which will not bring your face too close, the mirrors themselves may not have to be too long to get the field of view you need for the LCD screen. You may find the thing getting a bit heavy to handhold that far outboard and possibly vulnerable to transport damage.

If you need it to be shorter, you may find four smaller mirrors as a porro prism array may be easier to manage. You might be able to bring the viewport back over the top of the camcorder but the porro arrangement would be extremely ugly.

On "www.dvinfo.net/media/hart" under "aguserector" you may find some info on my experiments.

[Agus Casse]

hey Bob, i forget to post the solution for the image correction when shooting, i have a lot of work and the oportunity of my life in the door next to me, ( making my first tv show with my own company at one of the mayor tv station in Guatemala, and i am only 21 years old ! ).

So... have ever think of using a roof prism in the viewfinder in the camera ? not the big LCD screen, the little viewfinder, that we barely use cause we love the big screen :)... Well i order a few prisms and i test them with my TRV, (havetn test any of the adaptor stuff with my DVC80 yet.) and they work perfectly.

Heres the link and they are really cheap, i got 5 of them so i could experiment with a few of them.

http://www.surplusshed.com/pages/item/l2080.html

1 thousands thanks for keeping the Agus35 project alive, and hope to start working again in a new version. Thanks a lot Bob

Agus Casse

[Ari Shomair]

Agus; Its funny you should bring that up; I just ordered the same item last week and am waiting for it to arrive!