Homemade 35mm Adapter

[Louis Feng]

<<<-- Originally posted by Zac Stein : I don't understand why a concave lense just can't be used.

An optomistrist could make one, the quality would be excellent, it would cause no distortion and of course would totally invert the image. These types of things could be places just behind the lens mount, flip the image and bang directly onto the ground glass. Suddenly you would have a very small device.


Zac -->>>

It's not as simple as it sounds. You must calculate the focal point correctly to make proper size of the image. You must put the new lens out of the 50mm focal plane of the 35mm lens, plus the focal distance of the new lens itself, and the GG is going to be far away from this new lens. You are going to have a very long adapter.

[Craig Kitchens]

I found a company here that can make acid etched round glass for a very reasonble cost. I am in California. It is not perfectly circular but I plan to spin it at about 100 rpm. I won't be working on it until I get back from Christmas.

If anyone is interested in buying one let me know and I will take your order. I am not a shipping house but I suppose I could figure out how to get it to you.

One more thing, the quality of the etching isn't perfect either but it makes a very nice image.

you can email me at ckalan1@netzero.net or call me at 714 538-2484

[J. Clayton Stansberry]

I have finished my Agus35! The CD motor is really noisy (I don't think I have it balanced). And, I get lots of Flickering, but no vignetting. And, for some reason, I can't focus on things more than about 4 feet away??? I do not have a fresnel lens installed, but the DOF is better than the tests I did without the spinning CD. I used 1000 grit paper and sanded in one motion across the disk (I don't know if this is the recommended way?). Haven't tested in the light of day yet, so don't know the real abilities. Anyonen have comments? I will try to get some footage tomorrow that is acceptable to post...until then, let me know of any improvements I can make...thanks in advance!

Clay

[Agus Casse]

J. Clayton,

you are in the babies step yet, you have some problems with the distance from the SLR lens and the GG seens like it is too close or too far (my best guess is too close) the flickering is cause you probably didnt use a discman piece or it isnt well fitted, also remember that no all cds are perfectly straight some of them are bended a little.


About the shave machine and making this to vibrate... that is not a good solution, the noise is really high and you just cant get good results with it. if you are making this homebuilt the cd option is the simple and more effective way... and cheaper. And simplier to build.



BTW for everybody interested in the comercial version, i got some news... i got the prism and i can find more real cheap :) ... thanks to Guatemala cheap market.

heheheh no more info for now until i have some real pictures of this new baby. Also we are still working now in making an universal lens adapter. We have some ideas so stay tunned.

[Terry Wright]

Hi Guys

I made a mock up last night using a 35m lens, a cardboard box and a piece of 6x4" satin glass (4mm) that I just shoved through 2 sides.

When I put my Sony DCR-TRV16e into the box and output the picture onto my 32" tv, the quality was great. I didn't notice any grain and had little to no vignetting and I also couldn't see a light spot. The TV probably masked what little grain there was. The camera was attached to the box using a 30-37mm step up ring connected to the Cokin A series adapter ring which was drilled and screwed onto the box.

I'm going to play with it over Xmas and see how much grain there is when I view the video on my pc and then blow it up using Spline pro. If there is very little grain then I will put the project in a 4x4" box. I'm going to try some thinner satin glass to see if that yields a better quality image.

Regards

Terry

[Filip Kovcin]

Don Berube,

these likns are GREAT!!!! thanks a lot. i was searching for that kind of things for YEARS! thank you so much for that.

filip

[Jeremiah Rickert]

Does anyone know a place to buy a lens hood for a GL-1?

It seems it would be easier to use something that basically snaps into place for a mount on the 35 adapter, rather than something clumsier.

Of course, I don't want to use the only lens hood that I have, that came with it. I didn't see one on B&H...there was a GL2 hood on Ebay, but nothing for the GL-1

Any ideas?

Jeremiah

[Bob Hart]

A preliminary report on the pressing method of achieving a groundglass surface on a clear CD disk. So far, I get a sharp image on the screen, and it persists in low light. It is much improved when the disk is spun and flares from highlights seem to diminish. Getting a consistency of density across the disk is very difficult (Like I haven't achieved it yet.) With spindle motor speed at about 1500rpm, this causes a flickering effect which has been described here.

Microscope slides might be an option as raw stock for lapping fixed groundglass screens. It's a pity they don't still use large format glass slides for theatre advertising any more.

As a construction method, is anyone using a continuous length of PVC pipe 60mm OD or so with a slot cut in it for the groundglass rotary screen and adaptor pieces slipped into either end for the front lens and the camera mount or close-up camcorder lens. Some of this stuff is OD of 61mm, ID of 56mm and might have enough meat in it to support an external thread cut for the PD150/VX2000 camcorder family.

I propose using a short piece of PVC sewer pipe to align two PVC sewer end-caps for the groundglass enclosure. The 60mm pipe will go right through it hopefully preserving centricity of all lenses. It may be a bit large but may provide space for face mounting the switch, the spindle motor and a battery container.

Has anyone gone this route?

[Bob Hart]

I have sent some captioned .jpg files to Chris (kennelmaster)which hopefully he can post if they don't take up too much room on his server. Three demonstrate the distance between a 50mm objective lens from 35mm still camera and the groundglass image plane. A fourth demonstrates the light transmission through a "groundglass" CD frosted by means of pressing pits into the surface with a 500 grade silicon carbide "wet and dry" paper.

All images were originated on a PD150P, captured into Adobe Premiere 6, exported to .bmp files, imported to Ulead Photoplus 4, captioned then saved as .jpg files. After export as .bmp images, the pics are darker than they appear in Premiere or in the camcorder viewfinder. The image agus4.jpg was inverted and flipped but they have not been otherwise adjusted.

The fourth image is intended to demonstrate the light transmission through the rotating pressed groundglass. The sharpness or rather lack of it should be ignored as all components, the CD + motor, wires onto battery, objective lens were all separate and handheld together in a very awkward improvisation.

Lighting was by way of the ceiling lamps which were 3 x 60watt incandescent globes inside frosted dome shades. The camera was left to run wild and free on full automatic settings for exposure but manually focused.

The objective lens was a Fujinon 50mm as illustrated in agus1.jpg to agus3.jpg

The camcorder close-up lens was the macro portion of an Optex wideangle adaptor. It has a 46mm filter thread which was stepped up by two adaptor rings to the 58mm of the PD150. This put it forward of the PD150 front lens element by about 14mm so there is some vignetting on the about 75% zoom used.

Strangely, the flickering effect I observed by eye is not apparent in the camcorder playback.

There is granularity apparent in the image via groundglass. I'm not sure if this is the frosted glass or low light noise from the camcorder itself. On the other images which were also low-light some granularity or noise is also evident.

We live in interesting times.

[Don Berube]

>>>>Originally posted by Jeremiah Rickert : Does anyone know a place to buy a lens hood for a GL-1?... It seems it would be easier to use something that basically snaps into place for a mount on the 35 adapter, rather than something clumsier... Of course, I don't want to use the only lens hood that I have, that came with it. I didn't see one on B&H...there was a GL2 hood on Ebay, but nothing for the GL-1.

- Jeremiah, check again. Look for one that uses a 58mm screw-on thread mount such as this one from CAVISION http://cavision.com/LensHood/for_58mm_dia__shade.htm or one from CENTURY OPTICS http://www.centuryoptics.com/product...s/dvshades.htm. You could even try Google for a "58mm lens shade" or "58mm sunb hood". You get the idea.

- don

[Peter Sciretta]

Don - I assume he doesn't want to wear out his 58mm threading with the weight of such an add on... thats why he wanted to use the baymount connection....

but I could be wrong

[Don Berube]

Well I was thinking that it would be affordable that way. You could still mount it to the lens that way to have a firm "light-leak-proof" connection to the lens,,, but you would still need to use some rod support in any case - unless the adaptor created is very lightweight - at that point ity would be moot point.

If you need an OEM stock GL1/2 sunhood, contact Canon.

- don

[Daniel Moloko]

I did it.

just did it.

no moving parts.

Zenith Glass 50's gg

a black box.

Man, its incredible. believe me.

and it was a night shot.

i still just cant believe it...

i sent the .wmv to Taylor

hes going to put it online...get it, look at it.

man, what a >expletive deleted< great image.

no >expletive deleted< grain.

im sick

broken

and i just have to make a ring for my trv18 to adapt it propely.

the rest is rest. look at it.

[Bob Hart]

There'some large diameter plastic plumbers fittings (sewer pipe joiners) which look a bit promising for disk enclosures. There is a reducer which has offset centres, a bit like a funnel to look at. It is about 1/8" too small to enclose a standard CD but might be useful as an endcap to hold a lens adaptor.

[Spencer Houck]

Daniel, for the sake of everyone about to go CRAZY tryin' to find out what you've done after they wake up to see your post, what specifics can you give us on the camera you got the GG from?

Zenit, or Zenit(h), and what model. If possible, where did you get it, and do they have more???

I'm assuming the reason these GG's are working are that they simply lack the small circle of non ground glass that lies in the center of newer camera's GG's(for focusing). Am I right?

Any and all info you can give us would be most appreciated, as this would simplify the process to NO end.

Thanks again for pushing the progress further,
Spencer Houck

edit:
PS. I visited my local college camera store and picked up a +10 macro adapter with a 58mm thread for only 9 bucks! Guess this shows that we shouldn't always count on eBay for the best price/selection!