Noah: That's true. I asked the representative at SIS over the phone, and they only have 600 grit. I'm hoping to just use 600 grit, instead of using bigger sizes and moving down. I know this will be a lot of extra grinding, but I'm willing to give it a try.

If I need to, I'll get a 1lb container of 400 or 320 from Ted Pella.

Try here this is where I buy it.

http://www.microid.com/maison.htm

I can't imagine you canot find this in New-York.

Alain: It appears that your device is fixed to work with that specific 35mm lens. Have you thought about building one that is adjustable, to accomodate lenses with different flange focal lengths?

Alain--

Couple of things:

Could you post a close-up detail pic of the finished GG or is it "stuck?"

Do you think a electric grinder would work?:

http://www.amazon.com/exec/obidos/tg/detail/-/B0000AX9LG/qid=1075259921/sr=1-2/ref=sr_1_2_etk-tools/103-5922068-2900626?v=glance&s=hi&n=228013

If so, they have grinding wheel attachments for this tool that comes in the lower grit aluminum oxide the project calls for. Perhaps this would cut down on some of the labor??

Here's another place I found 120 and 240 grit Aluminum Oxide:

http://www.caswellplating.com/buffs/aws750.htm

It's brown though. Is there a difference between brown and white?

1 pound is $3.50. Cheapest I've seen by far.

I really don't know.
I haven't try this . The guy's at the telescope store tell me that the glass for microscope that need really precise grinding or for there photographique need are Hand made. Maybe you can start whit this for the first step but the first step is the shortest one,
forget about that for the rest, (I think) So your not gone a save time but I tell you again it's not that hard.

When I was at the store ,and the guy's explaine me how to do it ,I was a bit sceptic but when I start doing it I can't stop until it's done.

Alain

----Could you post a close-up detail pic of the finished GG----

http://www.kheops-tech.com/~ad3d/Aldu35.jpg

Heres a test chart for the optical quality of all of our mini35 designs. Any promising designs should be put to this test to know for sure that its working as well as it can.

It tests for:
1)chroma aberration
2)barrel distortion
3)how much grain is apparent from the ground glass

How does it work?

Step 1: Print out the picture of the test chart on high quality glossy photo paper at 300dpi. You'll find a link at:
http://www.cinematographerreels.com/mini35info.htm

Step 2: Measure the image after it prints out. It should measure 24mm x 18mm.

Step 3: Videotape the image with only the diopter lens your using in front of your camera (diopters are also known as macros, closeup filters, achromats and apochromats) and make sure its in focus and that you are filling the viewfinder edge to edge with the image.

Step 4: Post a frame grab from your video here at full resolution (720x480). If you have straight lines in your frame grab and no color blurring then your mini35 system has pasted the test.

Now if you want to check for how much grain can be seen in your ground glass repeat the first 4 steps with your mini35 system put all together including your 35mm lens.

These tests will check, with precision, everything but resolution. You'll need to shoot a professional resolution chart for that. Post that too if you have frame grabs.

Link to mini35 test chart:
http://www.cinematographerreels.com/mini35info.htm

Brett Erskine
Director of Photography
Premiere Visions
1761 W. La Palma Ave., Suite #302
Anaheim, CA 92801
www.CinematographerReels.com
BErskine@CinematographerReels.com

Any reason why the diffusers previously linked to won't work for this project? Aren't they just pre-ground glass?

Here's what I'm talking about... (http://www.knightoptical.co.uk/acatalog/DiffusersGlassdiffusersAnti-Newtonglass.htm)

Is it true that the grind, or frost, needs to measure in at 3 microns?

- jim

http://www.partsexpress.com/pe/showdetl.cfm?&User_ID=17946595&St=1723&St2=86832935&St3=-85385371&DS_ID=3&Product_ID=16106&DID=7

hi everyone wonder If this might be of help .
alain ...that is the most beautiful ground glass I have seen.
my test with the glass etching paste seems to cause what
look like pit,s and alain do you have a method for protecting the other side of the glass when you are grinding it. thanks for all the great photos

http://www.bealecorner.com/trv900/respat/index.html#EIA1956

This chart which has been recommended before in these forums can help you gauge the lines of resolution that your system can resolve.

I think I've stumbled upon another way to get high quality extremely fine ground glass. Use the stuff out of a hand held photographic slide viewer! I took a photo of mine at the link below.

http://uk.geocities.com/brian.wyndham@btinternet.com/index.htm

I've got a spare piece somewhere so I'm going to try basing my Aldu35 around this. Sorry if the photo is a bit poor as I'm still at the 'mess around with things roughly placed on a table' stage! But I tried the camera behind it and it seems to be a pretty sharp image. Now I just have to work out what kind of macro attachment I'm going to use (it's for an XM1). The Hoya combinations seem to be the best bet judging from what you guys have said yeah?

I'm really hyped for this!

simon, is the slide viewer GG glass or plastic?

www.knightoptical.co.uk/acatalog/DiffusersPlasticscreens.htm

Just looking at that it states.

"These Plastic Screens have still greater diffusion than ground glass types, allowing an image to be back-projected on a large screen without `hot spot’, and have a grey tint to minimise reflection of ambient and scattered light"

Would that be ideal for GG?

Put some scocth-tape on it to protect the other side.

for the monitor is the resolution good enought?

Alain

John, yes, I the screen is plastic.

I am also trying an inversion technique using mirrors (I tried a mock up with some mirrors that were lying around and it works fine as far as getting the image the right way up is concerned. Because it's done with mirrors the left to right thing isn't an issue by the time the image arrives at the camera. The image comes out left to right correct). The setup would be more bulky than Alains original design, but I seriously want to look at a correct image in the camera viewfinder rather than invert in post.

The pentaprism idea will get you an image that is the right way up but not correct left to right if I worked it out correctly.

Stewart--

Sounds like the plastic diffusers from Knight optical fit the project needs to a tee. Any idea the prices of these? Maybe one of us should buy one to test and report the results.

It says that they can custom make them too, which is nice.

The price is on this page (from 9 pounds for 3mm thickness):
http://www.knightoptical.co.uk/acatalog/DiffusersPlasticscreensSquares.htm

I wonder why they're talking about gain, do they have a Fresnel on the incident surface?

Also, has anyone considered if diffusion screens from rear projection TVs could be used? They get scratched so often, I imagine I could beg at a local TV repair shop for a couple of throw-aways, find one where the center part isn't scratched, and just cut to size.

Here is the test that I did , sugested by Brett Erskine.

I have change the lens from the optex magnifier for a lens that I took from a old super8 camera that is mutch better and the size is the same .Whit the test chart I notice immediatly how much distortion I get from this magnifier,So I chane it

There is a bit of lost of sharpnes and in light .this is shot whit a normal 60W light.



http://www.kheops-tech.com/~ad3d/test-chart.gif

Not too bad. You'll need to fill the whole frame next time you shoot the grid chart. If you can't you wont beable to use 35mm cine lenses correctly. But it looks like your already just close enough for regular 35mm still lenses so no huge loss.

I noticed it was alittle soft and had some chroma distortion starting to happen as you go out towards the outside of the frame. Sounds like your using a single element magnifier. Swap it out for a two element lens like a achromat (diopter) or for the best possible results a three element lens called a apochromat (triplet). Make sure it has enough magnification power and retest with the chart. Should make your setup work perfectly.

Brett Erskine
Director of Photography
Premiere Visions
1761 W. La Palma Ave., Suite #302
Anaheim, CA 92801
www.CinematographerReels.com
BErskine@CinematographerReels.com

I have just ordered 100x100 of the 3mm thick acrylic diffuser from knightoptical.co.uk

Will report back when I receive it, could be up to 7 days.

I talk to guy's that is an optic specialiste this evening and he say the same ting about the diopter,I need three lens for better result

I alway's thoug that one element is better than three in optic.
But no.

So I get back to work.

Alain

Alain make sure you dont just stack three of the same elements you are using right now. That wont work. Your going to need something called a achromat. Its at least two elements that are optically designed to work together to correct this problem. They are perminately cemented together when you buy them and are often housed in filter rings.

As far as having THREE elements its the same idea as I just mention. But in this case there is one more element that is cemented together with the other two. With this arrangement your sure to correct ANY possible barrel or chroma aberration. But there is currently conflicting information on the usefulness of the third element in the system as some say it only corrects for the UV part of the color spectrum while others say it also helps correct parts of the visible spectrum. Specifically the color violet.

Btw I think you finally convinced me that your ground glass is up to par with that last image you sent me of the resolution chart you shot. I didnt see any grain. Now lets all hope that the softness seen in that image will be corrected with the information Im giving here. Good luck everyone.

Brett Erskine
Director of Photography
Premiere Visions
1761 W. La Palma Ave., Suite #302
Anaheim, CA 92801
www.CinematographerReels.com
BErskine@CinematographerReels.com

P.S. THREE element corrective optics like I described are called APOchromat. Microscopes use them and they go way past 10X power but are too small to use for our purpose. Its a proven solution. We just need to find them in a bigger physical size. 58+mm I would guess.

Hi Brett,
AFAIK Achromat or Apochromat lenses are designed to correct chromatic abberations only and do not correct for geometric distortions such as pincushion/barrel.

There is some small problem here, but everything are only tape together

It's not perfectly aling


http://www.kheops-tech.com/~ad3d/test-chart2.gif

Alain

Check this link out if you're in the states:

http://www.poc.com/lsd/default.asp

This, too:

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

- jim

I just saw the test charts, the results are really quite amazing, but is it me, or in the last test i see a little grain ? is that because of the gif compression ?

Also, you can really fix the image distorsion if you use a fresnel lens, as now you only magnify, you need to correct that magnified image so the distorsion is minimal (Just like Daniel Adapter, which proves to work great with a 1chip 380k effective TRV18 camera )

We are now going to make a new system from this basic, but with the flipped image, i will try to get something done for next week.

Congrats man, and you are a great pionner and i admire your intuition and creativity to go a step ahead and come with great results.

Alain, fantastic work man, please keep it up.

My observations of the latest test charts are that, while the adapter slightly softens the image (probably due to it not being perfectly in focus on the GG) there is actually GREATER resolution being captured from the Aldu35 adaptor image than the image with stock lens. I'm not sure how that's possible but that's my read of the chart results...

By the way, even if that is slight grain and not .gif compression, I still think that image quality is MORE than acceptable for the kind of application we're talking about (guerilla indie film making!) Sure, no grain is better than a tiny bit, but I'd HAPPILY shoot with a tiny bit of grain if it meant wide DOF and a simple-to-make adaptor.

paulb

Alain Im very impressed with your results. What did you change on your adapter set up since your first test chart? The test were so good I just want to make sure----did you shoot the chroma aberration test chart with only your "magnifing" lens or was that frame grab shot with the whole mini35 setup put together?

Same question for the resolution charts.

Looks like Alain may have done it. Now a even harder challenge will be to get a similar system to work on the DVX. With its longer minimum focus and large lens diameter its going to be a bit harder.

Paul,
The extinction resolution between the straight and through adapter framegrabs are not comparable because of the difference in framing.

Alain, if you fill both the entire CCD capture area with the entire resolution chart (you're zoomed in too much at the moment) you'll have a far more realistic gauge of your cameras resolution and the loss through the adapter.

The arrow points on the edges should touch the edge of the framegrab.

Yesterday I change the magnification lense for a lense that I took from a old super 8 camera that I have sacrifice,(Shame on me), whitch is 50mm and the first test was from one lens only,like I say before I tough that the two other element are not a obligation,but yes it is , and the secon is whit the three element.
So yes it's just magnifing lens.

maybe I should post a photo of my working space , it look like sacrifice table.)

The resolution chart is whit the whole adapter.

I am starting production on a short film in 2 weeks and would love to use this with my PD150. Is there any way I can pay someone to build me an adapter cheap and quickly?

Does anyone have plans to post a tutorial on this? I have seen the images of the Aldu35, yet was wondering if there could be some instructions put with that. Also, this may have been discussed in the other static thread but, how do you determine distances of lens, GG, magnifier, etc? Aldain, the footage looks great! Looks like I am going to have a collection of A-35's...an agus35 already and looks like I'll have to build one of these too! Thanks for all the work everyone!

Clay

I'd like to second the request for tutorial, I'm a little lost on the technical aspects of this and how it all goes together.

The distances needed are the same for the Agus and Aldu -- you just need to setup proper flange focal length and get your ground glass within a reasonable distance from your video camera's macro lens so as to afford it enough room to zoom in and fill the screen with the projected image.

That's it.

I don't have the time/money/energy at the moment to put up a tutorial on a static solution, but plan to when the time comes (if no one else steps forward ahead of me...)

But, basically, you've got 5 objectives with this project:

1. Get a macro lens (http://www.centuryoptics.com/products/dv/diopters/diopters.htm) or macro filter setup for your DV camera that is +7 or greater.

2. Obtain properly ground glass (http://www.phototechmag.com/previous-articles/2003/mj-dokas/dokas.html), or similar material (http://www.knightoptical.co.uk/acatalog/DiffusersPlasticscreens.htm).

3. Assemble a light and dust-proof housing that attaches your adapter to the front of your DV camera, and can accomodate your ground glass, with a mount for 35mm film lenses (http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=77558&is=REG) at the front. I'd suggest making a trip to Home Depot and looking at the PVC they've got...

4. Place the ground glass at the proper flange focal length from the rear of your 35mm lens (http://www.gregssandbox.com/gtech/filmfacts/flange.htm).

5. Figure out a way to attach the setup to your camera (http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=126662&is=REG).

Should be even easier than building an Agus provided you outfit yourself with the right materials.

- jim

step 2a- (addendum) I believe Alain used a clear UV filter, and ground that down to a GG.



Thanks for the summary Jim

I may have found something that works. Last night I found plastic holders that you put your negative pictures into. If you hold them from a distance of something you can't see through it, but if you place it right on something it's clearer than tracing paper. I used it and it seemed to work fairly good. I think someone else should try it though, because my adapter isn't built very good and is hard to line up the 50mm lens correctly (it kind of sags down a bit. Hard to explain).

Anyway, this very thin plastic has no grain, but you'll want to keep it in the best condition possible. It's a semi opaque clear plastic material from a distance (if you hold it up to your eyes and put your hand about 6 inches away, you'll barely be able make out what' you're looking at), but looks highly tranparent the closer you get to the object (hold it up to your eye put your hand real close and you'll see it perfectly. Place it on letters and you can see them almost as good as looking at them without the plastic covering them, move the plastic a couple of inches above letter and the letters will virtually disappear).

Try it. This stuff came from "Longs Drug Stores" and holds your negatives.

Corey: I know exactly what you're talking about. Didn't think of that. Good idea!

My aluminum oxide should be here Monday. I'm really looking forward to trying to make a ground glass. However, I'm going to try the route of starting with 600 grit and grinding the whole thing with just that. I know it'll take a while, but hopefully I can get some acceptable results.

As with others, I will post some images as soon as I get something going. I must say that I am a little worried now that I realize I should have an achromat/diopter, and they cost way more than I was expecting.

Also, are any of you working on an adjustable version, to accomodate lenses with different flange focal lengths?

Hey guys do you think having a 30mm by 20mm gg will result in a significant field of view loss? I asked John Jay about it he said that it is possible to gain back the field of view by using a 35mm instead of a 50mm slr. I was wondering about the barrel distortion on the 35mm is it very noticable? Also does anyone know where i can find a fast 35mm and a 50mm lens with the same threading size. I am thinking of using zenit's b gg for this adaptor which is around 30mm by 20mm.
All comments are very welcome.

Corey

The idea about the plastic was great. As soon as I read that I went looking through my old photos and found some to try. The image did look great on the plastic, nice and bright and sharp. But even with my little Sony TRV-11 I could definitely see grain and imperfections in the plastic.

Great idea though.

also we want to try and stay away from plastic as a GG because its not very good at light transmition, like the plastic GG's in the Agus35. I had to turn the gain almost all the way up for a 'normal' image, u just loose too many stops.

Glass is BETTER!! the Alain35 is proof of that.

Actually...

Knight Optics claims their plastic diffusers are better transmitters than glass.

I've written them an extensive email inquiring about the plastic diffusion screen's optical properties. Here's to hoping it's worthwhile.

- jim

I'd like to compile a gallery of everyones projects for quick reference.

So if you need your images hosted somewhere and you'd like to add to this compilation please go to the galleria

http://www.visionengine.com/galleria

Everyone interested in having a static adapter built--

I've contacted a Chinese optics company about having these built once an 'official' prototype has been nailed down. If we can put together all of the detailed requirements, they will more than likely be able to build a quanity of them (they're waiting for the details and quanity). So . . .if you're interested in getting in on this for the cost of having them built, shoot me an e-mail with your name and camera type. I'll keep a tally and let everyone know the price they give me once everything is finalized. I'm not looking to make a profit on these at all, I just want something built professionally as I'm sure most of you want as well, and we can get the price down the more we order.

I'll also need an official specification. Whovever wants to provide that can send it to the company directly. Just let me know and I'll provide the e-mail. That way, whoever provides the spec can work with the company with whatever questions they might have. Alain-- if you end up being the one to provide the spec, let me know and I'll help you clean up your english. :)

Any thoughts on this? Feedback would be appreciated.

Oh, a couple of issues that I just remembered, is there a way we can make pretty much the whole adapter standardized for different camera types (except for attachment rings)? Also, do we want to include a 35mm lens in the orders, or do we want to be able to add our own? If we go the "add our own" route, what ring adapters should be included?

I think the 35mm lens should be left out as many of us already have one we could add. Having one in the price would greatly increase the cost. Stepping rings are again something that can be cheaply added seperately. I think just having the base unit made to a good standard would be enough. More importantly is some kind of supprt/rail system for it.

Todd,

as people reply to you they should be sure and mention for what camera they want it for and I guess maybe you should have a tally of what cameras are and the numbers of each.

Good idea, Kevin. Please be sure to include camera type in your e-mails.

Simon, I tend to agree. The only reason I mentioned the 35mm lens was because this company already manufactures them and I think they are pretty cheap. I'll get a price with/without just in case someone needs one.

Rods/rails will be very important for this and we'll want to inlcude rods support in the official design.

Ah well, if they do good lenses it might be worth it depending on the cost. Further to my email to you, I use a Canon XM1 (GL1)