I am sure that someone has already pointed this out earlier, but here goes. The frosted plastic that you are using in place of real optical ground glass is deteriorating the image too much. It is also causing you to lose too much light. Earlier, someone had posted something to the effect that "if you use ground glass, the image will be too bright". Well, if that is the case with this design, then the design is flawed and should be reworked so that you can use real optical ground glass. So far, none of the sample clips I have seen show an image that does not look degraded by the plastic. No offense, just an observation.

- don

Yeah, but expense and weight have to be factored into the design, as well.

I've got about five "ground glass" CD's here -- they cost me nothing more than I'd long ago spent on CDR's. If I drop them, or decide I want to mess with them to get different optical effects, I don't have to sweat their replacement and the costs incurred.

The question isn't (for me at least) 'How can I get the best image possible, at the expense of other considerations?', it's more 'How can I create an image that's acceptably interesting with the things I have at hand?'

- jim

I would still say that as long as you limit yourself to using plastic in the image chain, you will be self-defeating yourself. Why waste all that energy trying to produce an "acceptable" image with plastic when you have the potential for an excellent quality image with glass? It's a simple thing that we have known for years - plastic does not produce good results in photography.

You mention "expense" - what is your budget cap? C'mon save yourself a lot of frustration and wasted effort, spend a little more and put some real glass in there. I dare say that it is not impossible to find an affordable glass solution by modifying the design a bit. Regarding finding an affordable piece of glass - has anyone thought of using a 2mm thick 4x4 or 3x3 mist or fog filter from LEE Filters or Cokin? Or perhaps an even-more-affordable resin filter from LEE or Cokin? Even a resin filter would be much better than plastic - but you really should use glass.

Again, no offense implied here, I'm somewhat impressed with what you are doing, really. It's just that the image is too deteriorated.

- don

New version with higher res...

http://altoque.tv/35mmAdapter/35mmtestBETA.wmv

Don Berube is right we are loosing a lot of light and considering that still havent installed a dove prism to correct the image. Still, cost vs performace is amazing... DOF is great, my TRV18 is kicking ass with no modifications or aditional investment.

hey Jim, thanks for that credit dude !!

i see that you are having some vibration problems, are you using a cd motor ? did you sanded the cd or was a already frosted one ?

i think they can cut the glass center just like the cd, i saw some stores that have some glass windows with little holes. i will try up with glass next week if i am lucky, i really need to improve this for the comercial version, also i am still working in flipping the image.

agus - I think people would be satisfied in a commercial version if you could find either:

A. an output from the cameras RCA's that will flip the image normal for an external monitor/lcd

B. If you include an LCD that will flip everything.

I like the idea of the prism but I think it will cause too many problems plus it will just be one more thing the light must go through and will bring the light levels down yet again.

I don't think most people have a problem with flipping in post... the problem is to see everything as it is (right side up) while filming.

Agus, are those your sons or your nephews? They seem like good kids. You should name your device after them to reward them for tolerating your chasing them around with your device, which I am sure looks a little scary to them. hehe

Just curious if you could find a way to control the exposure more - so that you are not so overexposed in the white areas of the frame? It would be cool to see a nice flat, balanced exposure.

Is that sound I hear being made by your device? Is there a way you could deaden that sound? Reminds me of an old class at MIT, where the engineering students were given a Braun coffee bean grinder and the goal was to see who could figure out the best way to make the grinder perform as silently as possible. One solution was to deaden the walls of the coffee bean grinder with neoprene and to use a motor which was slightly over-rated for the task of grinding coffee beans. They lowered the voltage to that motor, so that it ran at only the torque needed to grind the beans and it was indeed a bit quieter. I would say that plastic shell of your device is resonating and somewhat amplifying the sound of the motor. Perhaps gluing a thin piece of neoprene inside the walls of your device (or around the motor?) would help mask the sound.

- don

yeah those are my newphies they are twins. :)

The problem really is that the mic of the TRV is less than 3 inches from the motor, so it is silent but the mic is too close. it can be solve using an external mic with no trouble. about the exposure, my bad i was so excited using the device that i didnt set it manually. but well :) i am so haappy that the optics are working well, and the image is not deformed like my first versions, and also there is no vigneting.

Don what do you think about a commercial version ? is flipping the image critical ?

Are you using a fresnel lens or macro between your GG and the camera Agus?

Yeah, a magnifying glass actually it is very powerfull i took it off froma wide conversion lens (VCL-0630 S)

Peter i still havent test using Glass, i am sure i will loose lest light with it than with a plastic cd, also the pentaprism or dove prism should be high quality to work...

I have figured out a static (no moving parts) solution. The test is very promising. I'm still waiting for parts to complete the whole thing. Once complete, I'll have an adapter which:

1. produce upright image
2. smaller (6x10 cm)
3. higher image quality and brighter.

The downside is that the complete cost to produce such adapter will cost a few hundred, might cost more depending on the quality of the coating and glass.

http://f2.pg.photos.yahoo.com/ph/lou....dnm=model.jpg

inverting ideas
 

<<<-- Originally posted by Peter Sciretta : I think, and I could be the minority but I wouldn't think I am... if it is a loss of quality or light steps flipping the image is not needed if you could somehow see the image right side up while you are shooting (ie flipped on a monitor or lcd).

I would rather that then lose quality. -->>>

peter,
(and others, of course)

i think that there is a place where you can put a prism for inverting!
if the small prism (DOVE PRISM) is mounted as kind of EXPANDER of normal viewfinder (between your eye and a viewfinder) - you will NOT change a picture (quality) at all, you will se everything in a proper way - but you will of course need to flip recorded image after the shooting.
considering small monitor already with the cameras - i think that VERY simple device can be added to commercial version of agus35 - small mirror laying down on one side of "LCD chimney" - so if you are turning your camera monitor bit down - you will look at that mirror which turns everything upside down. so the image foer the viewer will be again proper one.
does this make a sense?

For people who don't use the viewfinder as much as a lcd or crt monitor this viewfinder idea is not good. If you're going to do any handheld work we'll need to see an lcd right side up.

As for the mirror LCD idea, I implimented this with my unit weeks ago... this still has the BIG problem that everything is still flipped horrizontally.

The limiting factor of the current method (mini35) is the requirement of moving the GG. P+S was able to create something fairly small because they probably machined the parts as small as possible. The sole purpose of the rotating/vibrating GG is to reduce the artifacts produced by the coarseness of the GG.

I have been testing a number of solutions, ground glass and other kind of materials to produce a diffusing surface that is very fine, so fine that it appears to be white to the camera. With such surface, you can project image on to it and there won't be any noticeable artifacts. The result is pretty close, but not yet there. I'll let you guys know how it goes.

This is a very rough test of the my static solution. I am still looking for method to improve the quality. Especially in terms of transmitting more light and to be able to "distribute" more light to the corners. Maybe a frensel lens would help.

http://f2.pg.briefcase.yahoo.com/bc/...=/35mm+adapter

No Moving Parts
 

Hey, I tried to post this yesterday, but I may have found a way to not have to use a spinning CD. I had to scrap the spinning CD because of the size of my camcorder (which made it virtually impossible for me to have a spinning cd). The non moving method has no scratches, dust, etc. The image is bright too.

I used very thin, slightly diffused plastic and if i triple the layers it becomes diffused enough to create the projection. Worked for me. I was using other still pieces and the scratches from the sandpaper were just too noticeable. I knew there had to be an alternative. I'm not sure how it compares to the spinning CD, but it works for me.

Yeah, you need to zoom or magnify it. If you are zoomed in as far as possible, then you need to magnify it before you capture it. I have had problems with the vignetting, but that was due to my holes being off and not totally centered. I was able to zoom in a little more and that fixed the problem...this is just with the lens going straight into the camera without the frosted glass. Haven't got my hands on the sandpaper yet. Hope it works!

Don, that's a good one. Actually I think Agus's last video looks really good. However, it's an outdoor shooting, lighting is much more abundant in that case. I have yet to see anyone that can handle in door lighting well.

It should be noted that the video I shoot was shooting directly from the GG without any cover and was not modified or color corrected in anyway. I'm sure it will look brighter when everything is in a blackbox. But I'm not expecting dramatic improvement from this type of GG (hint, hint).

In fact I am wondering how good the mini35 is, considering there really isn't that much light passing through the lens. I don't believe there is any magic that somehow they can "squeeze" more light from how much there actually is. Again, it probably works well outdoor with bright sun light. I haven't seen any "bright" indoor shots on their web site (most are dark and smoky).

Having played with different kinds of real ground glass, I can tell you that the best/finest ground glass can only produce ok results in a static solution. However, there are other materials can do much better job, both transmitting more light and produce clearer image, but also cost a lot more. Let science do the magic, that's what I'm going to test next. I might even impress myself.

Regarding using ground glass/plastic/consumer products

All the materials above will work fine with a rotating/vibrating solution. The downside is they scatter too much light in every direction. They are not specially made for this video recording.

A static solution is even harder. Ground glass won't work, plastic CD won't work, any short of consumer product won't work. They all produce uneven illumination or visible noise.

I am only considering a static solution for myself, because it would be much more cumbersome to produce an upright image with the rotating/vibrating solution. The missing part right now is to find the best material for the projection. I might have found what I need. I'll know in a few days.

It's called...
 

Plastic Sheeting. It's real cheap. 3-4 layers should be enough. Works pretty good. It doesn't need to be rotated, because it's not all scratched up. I'm not sure how it compares to the CD though. I will see if I can get some photos or videos up later. I'm still having some vignetting issues.

If people want to go the non-moving groundglass route, then medium format objective lenses onto a larger fixed forsted glass might be the way to go., ie., bigger format bigger groundglass, smaller grain defects across the image.

It may be feasable to use the whole of a secondhand medium format camera or modify it to mount the small camcorder.

Charles:

I've got pics up but they're hardly conclusive:


http://ideaspora.net/agus35/front.jpg

http://ideaspora.net/agus35/rear.jpg

http://ideaspora.net/agus35/motor.jpg

http://ideaspora.net/agus35/assembled.jpg

http://ideaspora.net/agus35/motordetail.jpg

http://ideaspora.net/agus35/sanded.jpg

http://ideaspora.net/agus35/finished.jpg

http://ideaspora.net/agus35/finishedmount.jpg

http://ideaspora.net/agus35/finishedrear.jpg



I will have tutorial up by the second week of January.

- jim

To those who have completed their systems: what type/power macro lenses do you use? I know some have used the macro portion of their WA adapters, but some must be using regular macro/close-up filters. What power are you using? Can you zoom through these a bit and still pull focus on the projected image? Since this is the only portion of the project that involves purchasing a legitimate piece of equipment I'd like to be well informed about what works. I'd like this thing to be as compact as possible. Thanks!

gg from zenith 50`s
 

hello people.!

Vendi, you are wrong about NO GROUND GLASS that provides a good static solution.

I went to a used photo cam store and i found a cam by ZENITH that has a GROUND GLASS with a DIFUSING (fresnel?, im a brazilian, here we call it `lente difusora`)

lens attached behind it!

man, IT REALLY WORKS >expletive removed< GREAT

the GG was made 40 years ago. is perfect, besides only a scratch that i dont notice everytime.

and the grain is very little, it only adds a more film look aspect.

no vignette, no nothing, cause the DIFUSING LENS behind it just EXPAND the lens image to the WHOLE GROUND GLASS!!

if you tell me where to send the video i made (without the things adapted to a box), i will upload right now.

CIAO

"the grain is very little, it only adds a more film look aspect."

I said that no GG will work for high quality. You saw the grain, and I know exactly what you saw.

To me it only produces ok results. Try move the camera and have objects move in front of it, also try different light angles. The grain is certainly not film like, the grains are static, makes it look like it's shooting behind a glass (which is true).

If you scale your video to smaller size, this works fine, because the grain will be averaged out and not as visible. But for real things like DVD, or indy film, higher quality is needed. But again, Super fine GG will produce ok results, just not great. If you think it's good enough, then it's good enough.

If you want to produce an upright image, take a look at my design, better yet, improve it.

http://www.dvinfo.net/conf/showthrea...threadid=18690

Re: ZENITH GROUND GLASS
 

<<<-- Originally posted by Daniel Moloko : ...AH, the man who selled me, said that its almost impossible to find one of those these days!!!!
i bought it for 10$ .

NONE of others photo cams ground glasses is the same CLEAN as this one. -->>>

daniel,

i didn't tried it yet, but here in poland you can find TONS of that ZENIT (wthout "H") - if this is the same producer - this was USSR 35mm still camera. Are we are talking about the same thing? What camera (type/model) you have?

if you find it interesting - (the zenit ground glass) - i can check here and there and maybe send it where needed. i'm sure that you can find here zenit in proper working condition - the whole photo camera (WITH the lens) for 15-20$ max (which means that theoretically GG will cost much, much less).

so, if yo buy the whole camera - you can use the GG and experiment with the rest - the lens, maybe also pentaprism - who knows. but i'm not sure about packing and transport fees...
anyhow - at least you can try.
is it possible to find somewhere your tests with that ZENIT GG?

filip

Video from Daniel Moloko

Here is Daniels link
www.moorefilms.com/daniel.htm

about the teste
 

about the test:

it was just for you people to take a look at the ground glass.

and i just put it on the front of the lens i got. it doesnt grain.

anyway, i think its better than the AGUS rotating project cause the fresnel attached just does everything i need - no vignetting.

and if u think it is still graining, i say that it may be graining, but just as much as the spinning frosted CD.

Am I the only one thinking the non moving GG is great in concept but will not work in execution?

i think it would be awesome if it didn't move. then you woudnt need that big ugly cd spindle+motor. but, can some1 take a pic of their ground glass? i used 400 gritt and cannot see clearly through it so i am wondering how the camera would get a clear picture?

ground glass substitues
 

Might be of some help:

http://lists.kjsl.com/pipermail/acg/...er/000639.html

Someone talking about ground glass and substitutes he has tried (for making cameras).

Quote:

"I have used frosted acrylic film purchase in a tablet of about 25 sheets from an art supply store. This is intended for Ink Drawing and is frosted on one side only. It produces excellent images. It is available in different thickness. I happened to like 0.005" inch thick. In-fact I will be using the thicker sheets and plain clear-glass to replace the view-screen on a TLR I have been completely restoring. The plain glass will be on the outside to allow durability."


I haven't tried this as I am still waiting for a few parts, however, it may be a viable alternative to the sanding.


Best,
Von

"Am I the only one thinking the non moving GG is great in concept but will not work in execution?"

There are materials beyond ground glass and spinning cds. Don't be hasty, I have something in mind and as far as I can tell, it would be perfect for this application. But it's not something you can find in Walmart.

"i used 400 gritt and cannot see clearly through it"

400 grit? You'll see something better when it's over 1000 grit, and don't use sand papers, they only mess things up. Use these aluminium oxide dusts. But I can tell you that I have tried and it only gives ok result. For high quality, you need something more special.

For what it is worth, you may find the following Optics FAQ handy:
http://www.edmundoptics.com/TechSupport/optics.cfm

Optics:
http://www.edmundoptics.com/IOD/Browse.cfm?catid=10

Fresnel Lenses:
http://www.edmundoptics.com/IOD/Disp...Productid=2039

this looks very familiar
http://www.edmundoptics.com/IOD/Disp...productid=1966

T-Mount Adaptors (hmmmm...):
http://www.edmundoptics.com/IOD/Disp...productid=1460

More Lens Adaptors:
http://www.edmundoptics.com/IOD/Disp...productid=1459

Video Lenses?:
http://www.edmundoptics.com/Catalog/Custom/218.cfm

Cool!!!:
http://www.nightowloptics.com/addfra...product=NOCA42

- don

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

why waste time trying to invert the image recorded?

only needs to invert the display image, from the lcd.

anyway, lets try to make a motor function that do not spin like a cd and vibrates a ground glass. thats all


ciao

I for one, would like my image to be coming it correctly from the start to stop be stuffing around with it too much in post, i feel it is important.
Zac

I do believe that someone had tried using a shaver motor instead of a rotary motor and it was the noisiest thing to listen to... It was a nice, novel idea by Cosmin (Cosmin35?), but noisy: http://www.dvinfo.net/conf/showthrea...3790#post73790

You'd be better off using a miniature DC brushless motor with the proper tourque rating - it will be probably be almost completely noiseless.

You are making too many compromises by not inverting the image inside the adaptor with a corrective prism (or something like that). If you look at the links I left from Edmund Optics, you'll find the prices are extremely affordable. Read the Optics FAQ if you are unsure of what you need.

- don

<<<-- 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.

Etched Glass
 

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