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.

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.com/misc/letus/LetusTest1a.bmp
http://www.frozenphoenixproductions.com/misc/letus/LetusTest2a.bmp
http://www.frozenphoenixproductions.com/misc/letus/LetusTest3a.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/showthread.php?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).

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".

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.

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?page=overview&sub=lsdsheets
and
http://www.poc.com/lsd/default.asp?page=overview&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

guys,
check these out

http://www.poc.com/lsd/default.asp?page=overview&sub=lsdsheets
and
http://www.poc.com/lsd/default.asp?page=overview&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 (http://dandiaconu.com/gallery/album15), 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.

Dan Diaconu did a Beattie/POC comparison (http://dandiaconu.com/gallery/album15), 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.

Yes, we know at least the diffusion angle Dan used for his test. He said it was 50 degrees. I guess that is what he meant by 50%.

http://www.dvinfo.net/conf/showthread.php?p=306340&highlight=poc#post306340

It is quite possible POC offered this angle at that time.

Could be 50°, but we are still in the dark with respect to material and thickness, which seem to me very important. I am thinking that the screen Dan tested was not thin-film and possibly the angle is not optimal.

I just think that if I am getting much better light results from the materials I am testing, the POC guys must certainly have even better stuff. They show a graph where light transmission for a regular diffuser and a ground glass diffuser is at around 60%, and their materials are at 90% transmission. So it must be good.

Here is a DV AVI with two short segments:

http://www.filefactory.com/get/f.php?f=1851447f7e01e6c226bc1bbe

and a larger version:

http://www.filefactory.com/get/f.php?f=31be6373eb9476e79626f645

File was rotated 180 deg and recompressed as DV.

This is probably the device he's refering to: A Halina Viewer

http://www.danbbs.dk/~mikael/search/halina.htm

I don't know what gg he is using.

I got one of those secondhand for $5 or $15.

Perfect diffusion and perfect light transmissivity are mutually exclusive concepts. You can't have both. After reading a lot here, and doing a lot of experimenting, I'm pretty convinced there's no free lunch to be had in this department. From looking at intenscreen's tech docs, it would appear that intensescreen does a good job of diffusion, then immediatly redirects light back to the viewer using a fresnel...either as a condenser or a magnifier. I'm thinking that a fresnel mounted very close (like .1mm or so) to a spinning GG would offer similar? performance (about 1/2 to 1 stop gain)

Logically, to provide enough diffusion you need to scatter light to form an image. To much scattering = f/stop losses. Too little and you get my pro-mist low diffusion GG look. The only way IMO to get that stop of light loss back is to eliminate the GG altogether...but this would take a much larger CCD to duplicate the DOF properties of 35mm.

I think a fresnel lens will loose you res, and there is the possability of the camcorder pcking up the fresnel's 'rings'. The be honest, the frensel lens is doing the same job as a PCX lens, only slightly differently. But give it a go and see what you get.

Wayne, I think the advantage in integrated diffusion/fresnel solutions is that the fresnel is in direct contact with the GG surface, therefore max light redirection. I guess the question is, could you get a DCX that close without distortion?

Dennis, you are right. There is always a tradeoff. But I have found in my testing with these film materials, that I can get the same light transmission for different diffusion levels. So they may not be as mutually exclusive as we think. Of course you cannot have all light transmitted (not even a lens can do that), but we can try to get the best possible scenario. The advantage of the polymer materials is that we can get lots of diffusion for very little light cost, something that doesn't seem very easy to achieve with glass.

BTW,

http://www.poc.com/images/lsd/overview/lsdfilms_graph_b.jpg

That's the graph I was referring to from POC.

Wayne, I agree with your assesement of the fresnel. It is only acting as a condenser, just like a PCX would. The only difference is that a fresnel is very thin and therefore has less light loss, which is why I think they are using it on the Beattie.

Wayne, I think the advantage in integrated diffusion/fresnel solutions is that the fresnel is in direct contact with the GG surface, therefore max light redirection. I guess the question is, could you get a DCX that close without distortion?

Yes you can (well a DCX would touch just at 1 point, a PCX would touch on the flat side). Many SLR camera screens do it that way (Nikon for example). Just a PCX touching the screen. I don't think the "touching" is the critical aspect. BTW, the Beattie seems to use a fresnel that acts as a PCX with a focal length of about 150mm.

Besides, there are setups to reduce distortion, like using lens pairs.

I want to try a aspherical lens as a condenser. Anyone with experience with asphericals?

Alain, I've seen that graph...which makes the POC light loss a bit of a mystery. I would assume that no one has actually tried a 10 degree POC in an adapter yet. I believe Dan's test was at 50.

Alain, I've seen that graph...which makes the POC light loss a bit of a mystery. I would assume that no one has actually tried a 10 degree POC in an adapter yet. I believe Dan's test was at 50.

I sent a message to POC, and they have not responded, I guess they may have just received quite a few emails from people from the forum :)

If we can figure out if one of their films at some diffusion angle works for us, then we may just buy a roll for all of us ;)

Ha, I requested samples today. I was looking at some a few weeks ago, but the POC news in the forum was not postive so I didn't bother. It's worth a shot. Now my guess is that a few of commercial guys are sitting back right now and saying "Tried that, waste of time....."

Ha, I requested samples today. I was looking at some a few weeks ago, but the POC news in the forum was not postive so I didn't bother. It's worth a shot. Now my guess is that a few of commercial guys are sitting back right now and saying "Tried that, waste of time....."

Hehe, they will wonder if we are serious with all those requests.

I wouldn't be too certain with regard to the commercial guys, many of them are just like us trying out stuff. And I think there is ample opportunity to miss on details like thickness, material (polycarbonate vs. polyester) and diffusion angles. Get one wrong and you may think they all suck. :)

From my own tests, adapter aside, I believe that the screen material I am using at the moment surpasses everything I have seen (except for the Beattie) in terms of light loss. And my previous material was even up there as the smallest grain (but I got a rotational variance in the diffusion that gives bad bokeh). There is a material that already gives both great qualities but its not wide enough. (check out the Alternative screens thread)

Hey, I am an optimist! :)

Alain, are you still testing the Office Depot tape?

Latest shot at night out my window, porch light. I changed my condenser and got rid of the barreling I was experiencing with my rig. The light loss is about 1 stop maybe? Hard to tell, but definitely better than anything I have used before - home depot bags or anything like that is a great way to go.

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

leo mandy can u tell me how u apply the bag...do u glue it or something?

also, we don't have home depot here, but would these bags u refer to be the variety that come on a roll where you 'rip' them off for veges?

BTW how do u gauge light loss?

I've found a few bags. One is a trash bag. Not the kind you buy from a grocery store, but the ones a grocery store uses. It's very large and clear. Also, a doughnut shop has these types of bags. They use them to pick up the doughnuts most of the time. The veggie bags are about the same I think but I thought they seemed different to me for some reason. I'm trying this adapter as well and would like to know something. Do you apply these "bags" to a uv filter and make that a "gg" or just use the "bag" alone and add some condesors/macros? This would be helpful.

Rh

Yes, I just glued it to the surface of the CD.

In my initial experiments, I tried these shop bags as I had actually used one in a Muray 8/16mm home editor whose stick-on rear projection material had begun to peel off. Mine seemed to add a slight cyan hue but it might have been my imagination. Between two clear CD-R disks I found a flciker similar to the wax so I did not go furthur with them. If there is a better consistency of opqueness and thickness, one should perhaps give them another look.

So, would you guys consider this concept better for spinning/vibrating or for static?

Rh

A bit off-topic...

Where have you been hiding, Alain? You wrote some of the best trueSpace plugins around. Didn't know for sure if this was the real Alain Bellon or not until I saw that you had some images linked to your old site.

How's tungsten|SOLID coming along?

To get it back on-topic, nice images!

Frank