Havnt posted much for a while so I Felt like contributing a couple of stills of my homemade adapter (about 2 years old form the original Agus35 days) and a sony a1.

It was the first time i had shot with HDV and my adapter and the 2nd real short i have done with the adapter.

I shot the entire short with a 50mm 1.8 nikkor because it was a mockumentary type piece and this reall worked for it and this is the only good lens i have.

I have uploaded some pics of the cam and a still of the raw HDV converted to a jpeg.

ON another note I actually bothered to get a professional sound person for this short and made so much difference i strongly reccomend this to amateurs as to not get burnt.




Cheers,
Ben Gurvich

Hello again Ben.


Looks good.

Is the original disk still in your Agus35? If it is, that disk was also used to shoot two small music single shot videos. One, "My Time Again" is posted in truncated form here.

The lens was a $20 Cimko 28mm - 70mm zoom for Nikon out of Cashies discount bin.

It is a 9mb .mov file so takes a while to find its way down.

http://www.dvinfo.net/media/hart/agusdemo.mov

Bob,

Been a while, but yes i owe it all to this nicely machined up disk! and the lens ofcourse.

I tried a test with my cheap no name brand 28-80 zoom, but it looked terrible.

I enjoyed the A1 far more than the fx1, it was a bit more fiddly and expanded focus does not work in record.

Cheers
Ben

Guys:

1. With my DIY Micro 35 based roughly on Redrock instructions, I have a pretty significant noise coming out of the box. Maybe due a bit to the disk being unbalanced or motor noise. How do you get around that with on camera mics, or do you..

2. Is there any other source beside Redrock for disks. If not, suggestions for making own -- site references ?

The noise is a vexed issue with most home-mades.

Glass disks are heavier and almost impossible to cut circular to the same precision as a CD-R. DVD disks are not all that great either. You get some samples of these which will shake a player up so badly the tracker can not maintain the lazer over the line.

CD player motors are almost always rigidly mounted in Agus style devices. In the players they come, from there is one, sometimes two acoustic insulalion barriers to isolate mechanical noise

If it is a good finish on a full-size CD-R style disk, the disk is clean and no fingerprints on the groundglass texture, 1.5v DC which = about 1100rpm to 1500rpm for a 1/50th or 1/60th sec shutter in most cases is adequate. This reduces the noise dramatically from 2800rpm to 3000rpm you get from 3v DC.

Another trick is to select materials which are less acoustically live. I use a separate motor mount plate inside my device. This is cut from a sheet of polypropylene whiteboard.

Thanks, Bob, it looks like the plastic disk is the thing still. Have you made one your self from any materials, rather than have to put out $50 to someone else ?

My personal preference is the glass. I have been making these from full CD-R sized unfininshed blanks from Ohara in Japan but have not been able to source them since. The results are more controllable and predictable for me but there is a lot of process in it.

I have used the plastic CD-R clear spacers and these can look equally good. They are more easily damaged by cleaning etc..

I tried DVD spacers which are thinner, got one good one out of it, have not been able to duplicate it since and I damaged the original.

The formulation of disk plastic now seems tougher and seems to kill off my glass dressing mix which I was using.

Chris.

My adapter is based of this one here

http://www.mediachance.com/dvdlab/dof/index2.htm

there is felt pasted inside to try and minimise noise. I have not used on camera mics as they are really only good for quick tests or if its an emergency.

That said. I did play around with a single chip camera mounted to this box and recorded sound. From what i recall you couldnt hear the box.

Bob was kind enough to send me his old ground glass, without this i dont think the box would be half as good. I would listen to his advice as he has been working on these boxes for over 2 years (both the upside down and inverting types using prisms) and has been much help to homemakers on these forums.

Some cheap felt substitutes for sound deadening - I only have Australian details but they may well be available in other countries

The Mediachance design is a good one for the homebuilder, relatively bulletproof and lends itself to added innovations like backfocus adjustment and genuine lens mounts with little difficulty for the constructor.

The use of a square design and ply panels in three layers lends itself to stack drilling of centreholes and screwholes which is a near guarantee of accurate optical centre-axis and parallel alignments.

The published method of using thin foam sheet for acoustic insulation is equally valid and effective.


The substitutes :-

"Jif cloths" a cleaning product. Made in the form of a felt like product.
BARCODE - 9 300663 234684

"SUPERCHAM" by "ASHLEA - MILL" "LEES NEWSOME LTD" OLDHAM OL9 6LS
BARCODE - 5 017756 010486

When fixing these inside casework, use yellow contact cement but only a mere trace of it, - don't apply glue directly to the felt but spread some out thinly and evenly on a disposable surface, lay the felt substitute on it and lift off immediately, check to see if the glue is there in light bits and pieces closely grouped but not actually soaked into the felt.

Then if satisfactory, press this inside the case where you want it to go. Too much glue soaked into the felt will spoil the sound absorbing performance of the felt. It is okay to apply a thin coating inside the case, let it dry then apply the glued felt onto that.

The SUPERCHAM doesn't look too bad applied to the outside of a case either. Painted or dyed black it looks like the finish on the inside of a CP16 motion picture camera film door with the same pattern of fine holes in it.

I got lazy however and didn't finish the outside myself, instead did a quick paint job with hand brushed blackboard paint in my haste to go out and test the thing.