Homemade 35mm Adapter

[Bob Hart]

Furthur to above, I did not get to shoot any shadow footage to compare with the Mini35 on JVCHD250, of the music video today due to confined spaces and the urgency of keeping the shoot on time and on track.

However, the Mini35 had inhaled a piece of dirt from somewhere and it fell to my task to assist pulling it apart. The owner had some trepidations but also met the necessity of learning to do it on set for the sake of being able to in the future should such come to pass.

I had no such trepidations. The owner suggested such, knowing full well I would not mind in the least, the chance of peering into the entrails and reading its future. Well in truth, there was a little concern I might do harm however this concern was illfounded.

The Mini35, once dismounted from the camera is fairly straightforward to deal with for dust contaminants for someone with a small flat bladed screwdriver and good mechanical facility.

In this event, we dismounted the camera and dealt with the Mini35 whilst it was still mounted to the steadycam sled, a handy loft as it turned out..

Four screws removed and the back panel with the entire prism block comes out rearwards, cleans easily and goes back on within half a minute.

Interestingly for me, I had examined such a construction method for my AGUS35 but because I was designing something which could tolerate construction errors of up to 5mm, it was an approach I abandoned - stupid me.

They had a Seitz follow focus for the steadycam and set it up to run my 14mm and 20mm Sigma for Nikon mount ultrawides.

Although these are not geared, a rubber tyre created by a thick red rubber stationery band was sufficient for the follow focus gear to move the lens focus with acceptable accuracy.

Autofocus lenses when switched to manual offer very little operating friction, so the follow focus worked. I am not sure how much sideloading these lenses will tolerate over time, so proper gears should be fitted. If the lenses are allowed to hit end of travel, they will rock slightly in the mount.

All in all, an interesting exercise. I shall post the YouTube address when I know it.

[Bob Hart]

Deleted double post.

[Bob Hart]

Be careful what you post in the public domain.

A while back, I posted a clip of the Red Bull Air Race in Perth as a demo of aerial image relay via an Agus35 style device.

Now, clicking on the link yields a big red sign which alleges copyright infringement by myself. There is no means to publicly plead to the contrary and realistically would most likely clog Youtube into oblivion if such got started.

I posted into the clip description text, an explanation and expression of regret for inconvenience to people who follow links from here and other forums to look at the clips.

However, the explanation does not get to first base as the clip is excluded from direct linkage and the clip info can not be accessed.

I published a large diatribe in a centre section in this post but on reflection it served my need to vent my spleen but did little to inform so I have edited it out.

As you might guess, I am a little bit vexed. As a film-maker and writer, I am more sensitive than many punters as to the desirablity of respecting the original work of others.

The lesson I guess is. Don't point your camera at any public event as some corporate entity can claim dibs on your footage and turn you into a cheating fiend with the click of a mouse button.

To remove the red letter announcement from YouTube that I am an alleged copyright infringer, I have deleted all clips and am closing the account, so none of my youTube links I have posted in this forum remain working.

[Bob Hart]

Here are two new links for AGUS35 and LETUS35 origination to replace those lost when I closed my YouTube account.


The Eleventh Soldier. - http://www.brightcove.com/title.jsp?title=572028460

This clip was shot entirely with a home made AGUS35 device on a Sony HVE-Z1P.


b-movie heroes. - http://www.brightcove.com/title.jsp?title=570589631

This clip was shot direct-to-camera on Sony HVR-Z1P for the fixed high-viewpoint master wide,

direct-to-camera on a Canon XL1 for the fixed body level wide,

on a LETUS35 flip for XL on a Canon XL2 for the roving and close-ups

and on a home made AGUS35 device on a Sony HDR-FX1 for the point-of-view control booth with the blue microphone in shot at the head of the clip.

The resolution on Brightcove downloads appears better than on YouTube.

[Bob Hart]

For casual interest and to bring Agus Casse' original thread back up :-,

I have also done a short test of an Agus35 during other tests on a repaired CP16R Super16 gated film camera via the camera's 10-150 Angenieux lens and a Century +4 achromatic dioptre. The lens setback was not enough to use the +7.

A collateral benefit is being able to use a wider path through the prisms and thus a wider image off the groundglass at closer to 27mm and thus sneak a bit more resolution.

The 10-150 is NOT a Super16 lens but at about 7/8th zoomed-in it is.

The image outdoors looks a little oily compared to direct-to-viewfinder screen images with the same Nikon lenses.

I now have to how work out how to get good screen grabs.

Insane? - Probably.

[Bob Hart]

Regarding the AGUS35-onto-16mm-film test, I received a message back from the telecine place to advise me the film test was "all good". Does that also mean the AGUS35 footage?????????

Now I "am" looking forward to receiving the film and the telecine dub. The downside is I had to have it telecined to MiniDV so there is a resolution loss in SD. Still I can look at my pieces of film on a microfiche reader to see just how sharp it is.

[Bob Hart]

At the following YouTube address is the full version of the truncated motion clip previously posted at www.dvinfo.net/media/hart.

http://www.youtube.com/watch?v=Zxfjt0Y-EXk

This clip was shot with an early non-flip version of AGUS35 I called the Australian plumbers version because of it being built of sewer pipe and pipe caps.

The relay lens was made with the optics from an unbranded 50mm 2" telescope eyepiece for Tasco scopes. The packaging bore the product ID of SW5042. It comprised an achromatic doublet and a biconvex element. Used in reversed orientation, the biconvex element behaved as a condenser.

It was a powerful but difficult lens system to set up. The front of lens to groundglass distance was only 12mm - 18mm which enabled a very close couple to the video-camera. This was convenient for handholding but as a non-flip system, handheld framing and focus was very difficult.

I moved on to building an erecting or flip version using prisms and abandoned the telescope eyepiece optics for the less powerful 7+ achromatic dioptre which was set back from the groundglass far enough to allow the prism pair to be added between the dioptre and groundglass. No condenser was used in the prism version.

The distance from front of video-camera lens to this lens group was critical. Too close or too far and barrel or pincushion distortions became eveident.

The groundglass disk was a clear CD-R spacer, not glass. The initial groundglass texture on this disk was pressed into the plastic with 600 grade silicon carbide wet and dry abrasive paper and a generator bearing for a pressure roller.

The disk was later refinished with the more common method of aluminium oxide abrasive water slurry.

The clip was initially assembled and titled in Premiere6. The image flip was redone in Adobe After Effects and the filmlook methods published here at dvinfo were also applied.

[Bob Hart]

I had to do a shutter timing test with a CP16RA film camera converted to Super16 so also stuck the AGUS35 on front with gaffa tape and shot a short test of this as well.

The framing is a little bit wide as I do not have safe area markers on the film camera for Super16., so I picked up the edges of the prism path on the lens test itself. I framed wide on the test chart to show the edge of the disk and compare aerial image to groundglass image in the same shot.

I forgot to fit the 85 correction filter so the image is a bit blue.

http://www.brightcove.com/title.jsp?...nnel=570698206

[Bob Hart]

Another oldie.

This clip was shot on my first AGUS35, a non-flip version close-coupled to a Sony DSR PD150 PAL videocamera. TheSLR lens was a f3.5 55mm Micronikkor.

The adaptor used the reversed SW5042 telescope eyepiece lens set and groundglass made of plastic CD-R spacer, a sheet of 600 grit wet and dry silicon carbide paper and a generator bearing on a stick rolling back and forth across the paper on the plastic disk for about 40 minutes.

It yielded lousy resolution of 350 lines, lousy contrast. An initially dreadful thing to set up and try to use, I despaired of ever getting the it right and justifying my thus far wasted time.

Things slowly improved in increments from there. Some massage had to be done on the clip, like flip the image and mask off the vignette on the right hand side.

The clip is of Kim Bettenay singing his song "The Sock On Her Front Door", which features on his CD album "Strange Days".

http://www.youtube.com/watch?v=zBvAmbxMCA0

[Bob Hart]

Given that I have let the innards of a Letus35 see the light of day it is probably fair that I should let people have a look at what I have been cobbling together.

Apologies to Agus Casse. I have not kept it as simple as it could have been but I did try.

With the exception of the prism block itself and its relativity to the groundglass outer rim, construction errors of up to 5mm in some places can still be tolerated.

http://www.youtube.com/watch?v=CnweOEEqlRY

[Mike Dulay]

Is there a wrong way to mount a vibrating motor? I've made a mount from a plastic card for a Nikon F3 Type D. Because there wasnt enough room to mount the motor vertically, I attached it horizontally to the base of the focus screen. Looking through the LCD I can't see an appreciable difference in the grain fuzziness unlike a rotating ground glass.

http://www.flickr.com/photos/84946364@N00/458075232/

And are these supposed to be loud? Thanks for reading ...

Update: Used the Type D's tab as an anchor for the motor to mount vertically. But I still don't see the effect. Maybe the tube is absorbing too much of the vibration? Wish there was more space in this tube.

[Bob Hart]

Your arrangement can not work for the following reasons.

The vibrator motor movement is parallel to the lens centre axis.

A groundglass movement must be at 90dgrees across the centre axis to deresolve groundglass texture (grain).

The cut down plastic card does not appear to allow movement at 90degrees across the centre axis only parallel along it.

The cut down plastic card is a hard acoustically live plastic and the air space inside the tube will help amplify the sound much as a speaker cone and air enclosure does so what you actually have is a fairly efficient acoustic driver.

Assuming that everything is changed to move in the correct direction, what may also be against your combination of components is the relatively heavy mass of the focus screen versus the eccentric mass within the small motor.

The movement may not be enough to disappear the groundglass texture completely.

To allow movement across the centre axis but support the groundglass on the focal plane in a self-centering rest position, Quyen Le uses three pillars with flexible attachment points for his Letus35.

The system uses no control linkages to form the orbital excursion path which in its normal orientation becomes elliptoid, not truly circular.

The cinedof movement employs four more-or-less quarter-elliptical spring/control linkages to support a groundglass screen in a controlled movement across the lens centre axis.

The system uses the four linkages to provide a self-centering support for the groundglass and are intended to form the excursion path into a circular orbital motion.

[Mike Dulay]

Thanks Bob! I'm still trying to digest it. But I think I understand that the motor has to be laid on the same plane as the focus screen (vertical in my case) and center. The idea being to move the small grains in the screen in small vertical circles like when someone pans sand through a sieve (only a sieve is used horizontal). In this case, the holder shouldn't be too rigid or well attached to the tube body to allow movement. This is going to be a challenge.

My next hare brained attempt ...
http://www.flickr.com/photos/84946364@N00/458381455/
http://www.flickr.com/photos/84946364@N00/458381459/

[Bob Hart]

I recently exchanged messages with a video enthusiast at Youtube who linked me to a pic of his own home-made adaptor, an affair which used a frosted CD-R and appeared to constructed of pillar bolts and plywood panels.

It has to be the meanest looking machine that ever drew breath. But before one judged harshly, the foundation of the design included ability for a spring loaded, three-axis backfocus adjustment, in general the principle I followed.

Agus Casse's vision of 35mm adaptors for the masses lives on and people have a lot of fun doing it purely and simply.

[Bob Hart]

Here's some web addresses to some dated and useless information.


http://putstuff.putfile.com/87145/6797357

http://putstuff.putfile.com/87147/8689395

http://putstuff.putfile.com/87148/6909524

http://putstuff.putfile.com/87149/9241206

http://putstuff.putfile.com/87151/8192538