Homemade 35mm Adapter

[Ben Gurvich]

Im sure I posted a reply here last night? Dunno where it is

Anyway,

I finally built (had my good engineer friend Dave) the Agus on the Weekend using a varation on this design.

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

A short clip of the adapter on a single chip jvc cam is here on my website. http://www.benzenworlds.com/work.html
The color rendition is not fantastic due to the consumer cam.

I plan to shoot a short on it soon with the pdx10. And will post up some clips from that when i shoot in a few weeks.
I have a few grabs of the adapter i will post soon too.

Cheers,
Ben

[John Nagle]

Ben,

The tutorial you have posted is really excellent. Thank you very much for that and I am going to try it out this weekend.

[Bob Hart]

Digging down into the memorabilities of history back, at one time, there was talk of dove prisms for erecting images. I think the consensus at the time was availability of a suitably sized prism.

Today I went to a local camera service and retail outlet, Camera Electronic Sales and Service to buy a Nikon Mount to replace the crudely chiselled plastic mount on the AGUS35 I built.

The man behind the counter saw the appliance and suggested I take it upstairs for his father to examine. He evidently is a longtime builder and repairer of things photographic and fixer of the insoluble problem varieties that other people might prefer not to attempt. On his business card there are the words "Prototypes Designed and Manufactured to Order.

He had with him another visitor well knowledged in things photographic and they both got into quite a lively debate over the Agus35 and the objectives.

His initial comment was that I was cheating by using one. His store is stocked with a comprehensive range of still film cameras, especially medium and large format types and I guess that the unsaid message might have been "film rules".

During the discussion, he suggested that I was making life hard for myself by using two rightangled prisms to erect the image. At the suggestion of why I had not used a dove prism, I replied that as far as I knew, there were none available of sufficient size.

He picked up his telephone and within minutes upstairs came the biggest dove prism in the whole entire universe - or so it seemed.

So, with PD150 on a desk, 7+ diopter on the front, the dove prism on a phone book and a barcode to replicate the groundglass image frame 5 inches furthur away we looked. And yes, as quick as that, a dove prism does indeed work and is less complicated to set up than two right-angled prims.

The downside is cost, except in this instance his dove prism had come from an old microfilm (not microfiche) viewer.

The dimensions of this dove prism were 50mm broad x 40mm high x 95mm long.

It is a very heavy item and the physical length of an erecting Agus appliance with a dove prism this size would be longer than a right-angled prism version as the image path is not turned back on itself like with a right angled prism pair.

The upside is and it is a big upside, a common centerline applies as with the non-erecting Agus35 builds. The dove prism is also apparently more tolerant of off-axis misalignment.

So now I guess, there will soon begin a run on giant size dove prisms and old microfilm viewers and the world's ability to read its microfilmed history will suddenly be compromised by the sudden dissappearance of the remaining old machines and the gutting of their innards for Agus builds.

Smaller dove prisms may do the job but at least I can say that this particular specimen worked in a very hasty and improvised desk exercise.

He also referenced a US company which has been mentioned on this site often, Edmunds Scientific, as a possible source of dove prisms. ( I think I recalled that correctly ).

He then queried me on why I had not used mirrors. I said they needed to be surface coated. - Yes he knew that, then suggested that they may be found in cheap abundance in junked photocopiers, the only caveat being they would have to cut smaller.

His store has a website, "www.cameraelectronic.com.au".

[James Hurd]

Bob,
That's so awesome! Great news! So did you walk away with the prism??

[Donnie Wagner]

I've built a 35mm lens adapter for my Sony vx2000 Mini DV camcorder. In FCP, obviously there is an anamorphic setting in sequence settings and capturing settings, but it is only for 1.78:1 (16X9). Is there a way to tell the system that I'm actually using an anamorphic lens that compresses the image 2:1, or even 2.25:1? I think compressing the image manually after capturing will degrade the resolution.

[Aaron Shaw]

Are you using an anamorphic projector lens or an actual anamorphic lens (thousands of dollars...)?

What NLE are you using? You should be able to import the footage into a normal widescreen project and have it show up and process just fine. You will need probably need to stretch the footage out and then reimport before exporting for a final time so you get the right aspect ratio but it should work.

[Bob Hart]

James.

As I have already completed and am refining the two prism project I did not bid for his dove prism. Off the shelf he thinks new ones would be in the ballpark of AU$1000, which is a bit expensive compared to two right-angled prisms.

I posted the info for those builder-designers who are not yet locked into a design.

What is really interesting for a low-no budget builder prepared to go to some bother to set up a mirror path is his info on photocopier mirrors for a surface coated mirror source.

I have seen the things before but it never entered my head they were surface coated. One mirror strip would give you about four small mirrors if you could get them cut with no losses.

[Ben Gurvich]

If anyone needs a square 6"x6" project box mouser.com are the only place i could find one after about 4 hours of looking online.

Hopefully this saves someone sometime, from the finished result i think its was worth the time though.

Cheers,
Ben

[Danny Hatzi]

thanks Ben.
I might be needing this.

[James Hurd]

Bob,
I picked up a large dove prism from the surplus shed yesterday after reading your post for $29. It will give me something to play with....

[Bob Hart]

James.

Be interested to learn how you fare with the dove prism.

The manager of the store showed me another cute trick.

If you mount a large dove prism in a frame which can roll through 360 degrees around the center axis of the image and shoot an image through it, you can roll the image through 360 degrees by moving the prism.

[James Hurd]

So does that mean the image is only corrected at one position?

[Bob Hart]

It seems, that when the longest part of the dove prism is at the bottom, then the image of an upside-down object is upright.

I think I read somewhere that the image rotates 360 degrees for every 180 degrees the dove prism is rotated but my recollection is really quite vague so don't put any trust in it.

[Donnie Wagner]

has anyone attempted to use frosted glass as the GG? I know you can chemically etch glass with hydroflouric acid. A light (meaning not heavy) etching may frost a UV filter just enough to do the trick. Anyone know if this has been done.

[Bob Hart]

Its been done. For the Aldu application I understand the texture is a bit coarse. For the Agus it may be adequate but I understand there is no advantage over mechanical groundglassing methods.

It is not a place I would like to go as that is some serious chemical for amateurs to be playing with.