Wayne, thank you. It sounds like I was right about the alignment of the vibrator unit. All the images on that thread are dead though, so I can only try to make some guesses from the text.

That being said, I did a simple vibration test yesterday and it works nicely. I used soft foam to attach the base of the vibrating plate to the bottom of the adapter and it worked fine. I did not use the protruding arm concept that was discussed in the thread, but may try it later.

Bob, if I understand what you are describing correctly I think I know what the problems might be:

-It is not the same thing to press a liquid between two sheets of glass than to have a fixed cavity. When you press a liquid between the glass sheets, the liquid will spread but when you release the pressure it will naturally contract due to the lack of pressure and form the clear spots you describe (if I understood you correctly).

-The liquid must be contained to avoid spreading.

So if you make a cavity of fixed volume and seal the liquid inside, I don't think you will see any of the "cracking" you describe. Just because the liquid has no place to go.

I can imagine a few ways to construct such a cavity but will post once I have actually tried them :)

Here are some questions for you who are more experienced with working with lenses...

The suggested setup on the threads I have read is to place a PCX lens right next to the screen to serve as a condenser, and then another lens to be used as a magnifier (macro). An achromat is suggested.

Nevertheless, the setup I currently have from the slide viewer seems to work well.

http://mentemagica.com/35mmAdapter/Adapter1.jpg
http://mentemagica.com/35mmAdapter/AdapterTop1.jpg

First is the Nikon lens, then the screen, then, a couple of inches away is a PCX, and a couple more inches away a second PCX (the large one on the black plastic area that is tilted back). The screen I am using is about 5 x 4 cm and holds the whole Nikon lens image. After the first PCX, the image is about 6cm wide, still, I cannot get my GL2 to focus even on an image this large. So the second PCX magnifies it even further so I can focus.

From this I am assuming that no matter what marvelous screen I use, I will always need a magnifier (macro) lens.

With the first PCX a few inches away from the screen I get an evenly lit image, but I noticed something, if I move the camcorder closer to the viewer (closer to the second pcx), the image gets darker and I start getting vignetting.

http://mentemagica.com/35mmAdapter/FrameClose1.jpg

If I move the camcorder away, then the image gets lit better and the vignetting vanishes.

http://mentemagica.com/35mmAdapter/FrameAway1.jpg

The problem is that this makes my setup quite long.

(Note: These images are taken manually with a digital cam, not the GL2)

So my first question is: Should I adopt a different setup? Do you think I will get better results?

Second question: I want to buy better optics, should I get the highest magnification (smallest focal length) to reduce the length of the adapter or will that increase the aberration problems? Also, what about using an aspherical lens as a condenser? Will that work fine? (as I understand an aspherical will have less aberration problems).

Hi,
Regarding the vignetting, the behavior of moving the cam closer and further from the PCX is normal as there is a perspective shift while you do this. The bigger the camcorder lens the closer you can get with the same 'level' of vignetting.

To get your adapter shorter while keeping the image evenly lit, you will need a shorter focal length PCX (a little hard since you probably dont know the FL of the PCX in the slide viewer). Im guessing an 80 - 100mm FL PCX lens will serve you well with a GL2. Note that the shorter the FL of the PCX, the more chance of chomatic aberation and soft edge focus.

For the macro lens, try and find an achromatic lens for best quality

The first PCX has a focal length of about 100mm from my tests (this is 3.5x magnification). So I think I may need something shorter. I think I will try one of the Optosigma aspherical lenses as condenser (they have one with about 7.5x magnification).

The lenses from my slide viewer are suitable for testing but I want something better. Most of my light loss comes from them, they are very thick and the material is plain glass so they even look greenish when I put them on top of a white paper. I can't wait to test my screen with some more luminous lenses.

Another thing, when I pull the camcorder away from the second lens, the vignetting disappears but the more I pull back the more chromatic aberration I get. So it seems there is a trade off:

Longer adapter = No vigneting + some aberration
Shorter adapter = Some vignetting + no aberration

Even fixing the aberration through the use of an achromatic pair or triplet, will not solve the vignetting issue. So the first lens (the condenser) seems to be of extreme importance.

i tried the bag idea last nite. Its the plastic see thru bags for vegetables not the white plastic right? anyways.. that stuff had almost no light loss compared to prior materials ive tried. my kitchen at nite was amazing looking

for a liquid.. what about clear fingernail polish? i havent tried it.. because i dont have any...

Fingernail polish sounds interesting...hope somebody tries it.

Then how do you keep the paint on your nails from chipping? I have to use two coats!

:)






10 character minimum

i went through all of my gf's stuff.. she only has coloured stuff.. does anyone know if a couple even coats might work at all?

Hey guys I tried a bag that Ben had talked about using, and I was amazed by the result. I have to thank Alain for even coming up with the bag idea it was genius. check out the first test with a home depot screw bag at

http://irezfilms.8m.com/BAGTRY.mov

I have closed all my previous video samples

Bryan,

Looks good! You used a simple home depot plastic bag?

Alain Bellon, Bryan Ramirez,

please! is it possible somehow to BUY that bag from you? i'm so jealous - i can't find it here in poland. tryed in 20 different shops (different suppliers) - and nothing is even CLOSE to that. PLEASE! i am ready to buy the "interior" of that package (ham or hatever:)) for your pleasure :)

let me know if this is possible.

thank you,

filip

Filip,

Send me your home address to my email account and I will send you a bag or two.

Bryan,
Was that a static adapter? It looks like it, very nicely done. The colours are great and the image is crisp. I think Alain is onto a winner. Which adapter did you use?

Leo,

Did you have any problems removing any wrinkles? If so, how dod you remove them?


I see some vignetting in most of the clip, what adapter are u using?

You have to stretch the material out over a surface. I used a 58mm filter removed from the frame.

Thank you for the nice comments. It was a Homemade static adapter, and yea it was the bags you can get in the nail and screw department at Home Depot, The wrinkels, you have to find some area on the bag that doesn't have as many, then you just pull and tape the ends to what ever your using. I was very surprised. I'm actually going to get some old pagers today to take the vibrating motor out and get it on my " GROUND PLASTIC BAG ". I am having a vinnegting problem but Ill fix that eventually.

Where the ..hmm...funky(?)... did I burn my fingers for! Not too long ago I picked up my pre-heated glass before putting it into the melted micro-wax. Let me just say it was hot and I dropped it on the floor.

No, seriously, this is 'good stuff', I tried the same thing a year ago with some kind of air-bags that came as packing material with a printer. It was too grainy so I dropped the idea. (I used it as GG for my MF rollei photo camera though)
How's the grain (in uncompressed footage)? From the first images it looks like the grain I get with Paraffin wax. Other images look even better.

Test bag footage, likes and dislikes
 

Well, here are some screengrabs from some test footage of the bag with my Letus' focusing screen distance corrected and the condenser distance corrected as well:

http://www.frozenphoenixproductions....etusTest1a.bmp
http://www.frozenphoenixproductions....etusTest2a.bmp
http://www.frozenphoenixproductions....etusTest3a.bmp

Here's the issue: This new thin-film stuff produces some of the most sharp, bright images I've ever seen from any of my adapters, but the bokeh is absolutely horrendous, and I don't know if it's my condenser distance or not but I'm getting massive chroma separation. The bag doesn't seem to handle "too much light" well. I guess there'll always be trade-offs...

I'd try a gray filter. Stopping down the lens (on either one) will only increase the vignetting. A central grad filter like Dan suggested would be even better.

When you talk about Bokeh, what exactly do you mean? The term Bokeh, as I have known, refers to out of focus blooming of bright areas. I have even makde software to simulate this bokeh blooming (circle of confusion type) on stills and video.

Do you have examples of the type of Bokeh you do like as compared to the thin-film plastic bokeh we are getting?

Here is my latest test. Still using my static viewer adapter, which is not great.

http://eccentricgenius.com/AdapterTest31_W.wmv

Yeah, I thought the bohek was the proper way to explain, but maybe not. It is like the background is not gaussian blurry, but rather sharp blurry and somewhat unnatural looking (this is with the spinning CD plastic bag). I guess Iwill have to do some screen grabs tomorrow to show you. It is really evident with outdoor shots. Also it is a shame because the indoor shots, even in low light, are amazingly bright!

Here are some shots from the recent tests:

http://mentemagica.com/35mmAdapter/AdapterTest29.jpg
http://mentemagica.com/35mmAdapter/AdapterTest29a.jpg
http://mentemagica.com/35mmAdapter/AdapterTest29b.jpg
http://mentemagica.com/35mmAdapter/AdapterTest29c.jpg
http://mentemagica.com/35mmAdapter/AdapterTest29d.jpg
http://mentemagica.com/35mmAdapter/AdapterTest31.jpg
http://mentemagica.com/35mmAdapter/AdapterTest31a.jpg
http://mentemagica.com/35mmAdapter/AdapterTest31b.jpg

The last ones are from the video I posted earlier: http://eccentricgenius.com/AdapterTest31_W.wmv

I have a possible explanation for the strange blur:

Ages ago I used a digital slr without a focussing screen (don't remember the name, though, some Pentax I think). You were kind of still able to see the correct field of view (right past some mirrors through the lens), but it was virtually impossible to get the focus right.

So based on this, here is my guess: The "bagscreen" is too translucent.
You get the sharp image (straight through the lens) mixed with the projection on the bag. So what you see is the shallow DOF image mixed with a long DOF image straight through the lens (but not diffused by the screen). Hence you get a blurred background with the unsharp objects having a somewhat sharp "core". This does also explain why the images are so unbelievably bright.

At the risk of sounding stupid, you could try to use two layers of the material. I would try myself, but I don't have such a setup yet.

This is exactly what I've been dealing with my low diffusion GGs: http://www.dvinfo.net/conf/showthrea...t=58018&page=4
There are clips on that page demonstrating my adapter with a low and high diffusion GG. Normally this wouldn't be a big issue for film, as once the shutter is tripped, there is no place for the light rays to go past the film or CCD. With these adapters, there is almost an opportunity, if you want to look at it this way, to play with the image a bit as the camera is behind the normally impenetrable film/CCD plane.

The problem with thin films is that other than doubling or tripling the membrane, you can't tune the diffusion level. With a spinning GG, I'm finding you need a fairly coarse finish to achieve the look of a finite image plane....far coarser than this plastic material. I've now spent about $200 trying to get the "perfect" mix of adequate diffusion, and grain-free image on my little 85mm discs. What you see in the clips on page 4 are the extremes...too fine, and too coarse (at least at 1/250s shutter).

Thomas, actually this is not the case. If you look at my diffusion tests earlier on this thread (where I first talk about the screen on my device) you will see that the diffusion is absolute, meaning that you cannot see anything past the screen after you have separated it from the image more than 1 cm. There is no "ghosting" or blending of images. This is why I took care to explain the difference between good diffusion materials and just translucent ones. I think the whole explanation (with tests) is on page 1 of this thread.

Dennis, this is a different issue than what you are having. As I just described.

Yesterday I found something that may explain the bad "Bokeh". Some of these thin-film material's diffusion is not invariant to rotation. This means that they spread light more in one direction than in another, this is very obvious when testing against a light source. The good news is that I found some materials that have rotational invariance, so in theory they should produce nice bokeh. I will test this later today.

I'm not sure they're different issues Alain...but I'm no physicist either. My fine diffusion disc is absolutely opaque to an object a very short distance from it. In the light diffusion disc, I'm not seeing ghosting or blending...just a look that is not typical. I'll admit I'm no expert...so I'm happy to stand corrected if need be.

Dennis, ok. I thought you were referring about a problem with ghosting, which definitely doesn't seem to be ocurring on this screen. But I will double check just to make sure. If it is happening I'll let you and Thomas know right away.

Here are some new tests with a screen with less rotational variance:

(excuse the bad framing, I forgot to check that on the monitor)

http://mentemagica.com/35mmAdapter/AdapterTest36.jpg
http://mentemagica.com/35mmAdapter/AdapterTest36a.jpg
http://mentemagica.com/35mmAdapter/AdapterTest36b.jpg
http://mentemagica.com/35mmAdapter/AdapterTest36c.jpg
http://mentemagica.com/35mmAdapter/AdapterTest36d.jpg

As you can see there is some change in the blooming, but also there is more grain (not an issue for a moving adapter). Also, light transmission is even better.

Oh, and btw, I started a new thread to focus only on the screen issues. There are some pictures there of the rotational variance of the two different materials:

http://www.dvinfo.net/conf/showthread.php?t=58929

I was just taking a guess, based on my experience. I'm no physicist either. And I think your interpretation of the results sound better and very well reasoned.

And the new test .jpgs support your argument very well (and look great).

What I am thinking right now? Yippie, the bag idea is not dead yet. This is great news for me so I can upgrade my letus some time in the future.

Thank you Alain, I am honestly very grateful for your work.

Ok, hopefully I willpost some home depot bag shot tonight with the spinning CD. It might be better or worse, I can't tell right now.

I just added vibration to my setup, so here is the new screen with no grain! The screen is bright.

http://mentemagica.com/35mmAdapter/AdapterTest53.jpg
http://mentemagica.com/35mmAdapter/AdapterTest53a.jpg
http://mentemagica.com/35mmAdapter/AdapterTest53c.jpg
http://mentemagica.com/35mmAdapter/AdapterTest53d.jpg

The are a bit over exposed and yes I didn't check the framing again, hehe.

Stills look great!
Any chance of posting a photo of your whole rig?

guys,
check these out

http://www.poc.com/lsd/default.asp?p...&sub=lsdsheets
and
http://www.poc.com/lsd/default.asp?p...w&sub=lsdfilms

i guess dan has used them once and refered lightloss as the issue. Its a trade off between light and grain. if there is no visible grain and probably 1 or 2 stops light loss, then i would go for it. and then its a lot more cheaper than rotating/vibrationg adapters.

krishna

Excellent information Krishna. If you look at the film table, you will see that the polyester film has rotational variance (different diffusion angles horizonally and vertically). In the films I have tested the light loss is very little. I will certainly try these.

Thanks!

IS that with the new pharmaceutical bag? Darn it, that looks good!

Amazing. Truly outstanding.

I think I will upgrade my Letus ... with a pharmaceutical bag ;-)

I'm very happy about this possibility.

The POC solution is more like 4 F/stops! That's why it's not being used. Any chance of a few seconds of uncompressed DV on this? The stills look great!

Here is the spinning CD homedepot bag- night time, house across the street lit up with a porch light only. Compared to other things I have used in the past - this is gold - in the past, I wouldn't even be able to see it with mylar, wax paper etc.

http://dvstuff.250free.com/bag.htm

I also shot a small image with a light pointed away and behind a bookcase and it came out spectacular as well. Day shots in the next few days to compare.

Dan Diaconu did a Beattie/POC comparison, but it looks like he used a POC screen with an angle of diffusion of 50%. As Krishna says, there must be a compromise between diffusion/light loss somewhere with this material.

Well, there is some wrong information somewhere. What is a POC 50%?

The POC screens come in different forms (sheets, films, etc) and in different materials (polycarbonate, polyester, acrylic, etc). So knowing the thickness and the type of plastic is very important. Then, the diffusion angles they offer are 0.5, 1, 5, 10, 15, 20, 25, 40, 60, 80 degrees for the circluar diffusion ones (rotationally invariant).

So I don't know what POC screen Dan was using for those tests.

I suspect that the best POC materials should be at least as good as the thin-films I am testing, which does not appear to be the case in those images.