nicholi,

just great link!
i was surfing on the net just to find single place with everythig about prisms explained and showed. i already have tons of different jpgs. from many places, but this one RULES! thank you for that.

filip

p.s.
did you tryed to "construct" something with sowtware mentioned there? how it looks?

does anyone knows about free software for prism "construction" and virtual testing?
i mean - i'm not expert on optics, but if that kind of software exist - then (i suppose) is much, much more simpler to make your own construction of static adapter. i'm confused when i'm checking different prism - how and why certain picture will look. will it be reversal, left-to right or what...

any links are helpful.

filip

p.s.
i checked the link mentioned by nicholi and there is demo etc. but with some options disabled... :(

How about working this in...

http://www.optima-prec.com/prism.htm


Great work guys! I think what you're doing is awesome. I come from a still photography background and also thought Boss Screen might work, but the temperature would be an issue. I have a DVX100 and I intend on using stacked achromatic diopters. Any word on exact prism sizes and sizes of the hologram material? What should I get for a 72mm lense? All the best in your endeavors. I'm eager to try this myself.

Best regards,Mike

I'm a bit of a neophyte when it comes to prisms. How does an anamorphic prism constructed to regulate laser beams correlate to prisms that reflect pictures? Is there a difference? Does it control the light better than say a holo-difuser with a 10 degree light scatter? It's anamorphic, so, does that mean it captures or transfers a larger picture? I'm using the DVX100 as well.

You know what Dean, I'm not well-versed in this either. Maybe it doesn't need to invert, just project an anamorphic image.( if that's what this prism even does.) I'll try and contact the company today and find out. Best- Frank/ Mike, actually my middle name is Mike and that's what everyone calls me and for some reason, I put Frank as my user name. But I answer to either and I've certainly answered to worse. :)

Great work folks! Vendible I've been following your idea from the Agus35 posts. I also own a DVX100 and pending your experiment on the 10 degrees Holo diffuser, I will place an order for two.

Lewis, in regards to your holographic material, and forgive me if this had been covered in another post, is there any way to introduce illumination to it? I.E. It is isolated somewhat from the prisms, correct? Is there anyway to expose only the holographic material to illumination of some sort. Just curious. Best- Mike

hey, daniel!

did you finally find that guy who has a shop with full of old zenits?

did you find the exact model where from yo tooked your GG with no grain?

filip

p.s.

need this info desperatelly!!!

Beattie bright screen.

http://www.tallyns.com/Beattie.htm

the beattie screen looks interesting. I've asked them about the size and micron thickness.

<the beattie screen looks interesting. I've asked them about the size and micron thickness.>

I just pulled the focusing screen out of our Hassalblaad, and it's 2 1/4 x 2 1/4". I'm not sure about the thickness, but it's about like an acrylic lens filter. The Beattie screan should be about the same.

That's about the same size as the holo. if it's about the same thickness as an acrylic lense - I'm going to guess about 3 microns? Mark - does that sound right?

louis,

did you finished your holo35?
any news, any photos?

just curious

filip

Hello everyone. Until not too long ago I thought I was the only one that had tried to build my own Mini35. When I found this thread I was inspired to get working on the project again. Its nice to see there are more people putting their heads together on this problem. Because I wasnt bouncing my ideas off of anyone my design has evolved totally seperate from you guys and while we have gone down similar designs paths I thought I would bring up some things that have been totally over looked and sooner or later we are all going to have to deal with if we are striving for perfect looking footage:

1) Apochomatic Lens - for just about anyone planing to use a 3CCD video camera other than a XL1 your most likely going to need some form of a diopter/closeup filter lens in order to both keep in focus and fill the frame of our target object size: a 35mm film gate (same size as the inside of a individual film slide mount).

But two problems arise when focusing on something so close to the cameras lens.

Spherical and chromatic aberration.

Spherical aberration is the barrel effect you see exagerated on extremely wide angle lenses where straight vertical and horizontal lines of a given subject are bent outward as they approach the outside edges of the frame (fisheye effect). Your going to see the same unwanted effect (although to a lesser degree) when you try to capture that image projected on the ground glass. Try shooting a grid with your current homemade mini35 setup and you'll see what Im talking about.

And if you look real closely you will also notice the effect of something called chromatic aberration at the outer edges of the frame as well. Its characterized by the bleeded and blending of colors along with a over all ever so slight out of focus appearence. Technically speaking this is due to how different wavelengths (colors) of light react and bend at slightly different degrees as they go thru glass (ie a prism's rainbow)

But dont worry. Im not only the bringer of bad news but good as well because both can be corrected for with prefection with what is known as a APOSPHERICAL compound lens.

Which brings me to one of the reason why I temporarily dropped the idea of making my own a long time ago. I can't seem to find someone that manufactures exact what we need:

-----------a APOSPHERCIAL Macro Lens------------

In my case one with a +10 to +12 power because I have the DVX100.

So I hoped we could put our heads and resources together to find one. I tried Edmunds Scientific. Nothing. Anyone have any other links?

Brett Erskine
Director of Photography
Premiere Visions

Hi Brett,
I have started a post over at

http://www.dvxuser.com/cgi-bin/DVX/YaBB.cgi?board=news;action=display;num=1070228577

there is a fellow from Century optics who has put up some specific information relating to the dvx and correct lens.

Hope this helps.

ha ha I ment to say we needed a:

APOCHROMATIC Macro Lens

not a apospherical.

-Brett Erskine

Some folks were using, or planning on using, Century Optics' achromatic diopters. The apochromatic are basically a step above achromatic. Just so everyone can understand exactly what these lenses accomplish, here's a link: http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/aber2.html.

"When we speak of correcting chromatic aberration, the term should not be taken literally, as meaning "eliminate," but should be understood more in the sense of "suppress." from the link below:

http://www.astronomysite.com/mapug/13/msg13371.htm

This guy tells the differences between apochromatic and achromatic with a discussion of is it "worth" the extra$. It's for telescopes but is salient.

He also discusses 3 element acromats (l think Edmund has these)

Since it seems that the blue spectrum aberrance effects the image would an 85B filter in front of a acromatic lense work to correct the light?

I looked at the movietube construction and saw that it uses a special developed microcrystalline grain glass as ground glass. Couldn't we use a normal piece of glass and wax it with microcrystalline wax to get almost the same effect? Just an idea.

<<<-- Originally posted by Anders Floe : Couldn't we use a normal piece of glass and wax it with microcrystalline wax to get almost the same effect? Just an idea. -->>>

Anders,

do you have any links to that "microcrystaline wax" i have no idea what it is?

filip

Hi, Filip

There are many different kinds of micro crystalline wax - Here is one : Micro Crystalline Wax, white color, 140mp is used for preventing bubbles and mottling defects in candles. Its melt point is very high. It is white color too for use with paraffin or any other wax.

http://www.capricornslair.com/ligmiccryswa.html

Another different one :

http://www.spwax.com/spparaff.htm

I really have no idea if it might work, but if the wax creates a fine layer of micro crystalline on the surface - it could work!

The apo triplet the author is talking about is mainly used for astrophotography and so the range of wavelengths they are looking at extend beyond the visible spectrum.

the violet bloom they are talking about is in the UV spectrum so is of no concert to us.

According to scientific sources on the web the CCD acts differently than an eye. It specifically says that the chroma problem that apochromatic fix with visable color of violet and on into the UV range is often a factor for CCD sensors and image capturing devices.

I'll send the link soon.

-Brett

hey louis... you've been absent from this forum for quite a while now... how about them holographic screens?

I remember the longest time ago on the agus thread there was talk of having actual plans... seems that topic dwindled to nothing... seems like that would be the best thing to really work on to jump start some real progress again around here...

sorry, it just seems like nothing's really gone anywhere for the last 3 weeks or so

I have been wondering the same thing? I guess with the holidays and such people have been doing other things. I still have questions as everyone does about how to keep the dust or particles from showing up on a static capture screen. Maybe this is a problem?

So, now that we know what kind of GG the movietube use, is anyone willing to try to replicate it ?

Seens like the whole project is "stuck", and too many theorical information, but still we dont have any good results, about the static method, the only one that has good results is the Daniel adapter, which's images kick ass BTW.

So, who is really working in building it ?

Keeping the static "ground glass" clean is always going to be the draw back to a design using a static ground glass.

Probably the best and easiest way to keep it clean is to isolate it in its own clean chamber.

Just as in the example of lets say three round filters stacked on top of each other. If they are first spotlessly cleaned and then threaded on top of each other the center filter is unlikely to ever get dirty.

When it comes to the design of our adapters there are any number of places we can choose to put the front clear and rear clear barrier on both sides of our ground glass. One thing to keep in mind though. Dont put either clear barrier too close to the focal point on the ground glass other wise when the barrier itself gets dirty your likely to see the dirt (slightly out of focus) in your shot. Well need to eye ball it untill the glass barriers are far enough away that dirt will be completely out of focus and unseen. Its been awhile since I tested this but as I remember it it wasnt but a inch or so. I'll try and check it again soon.

If you try to do this method of keeping your ground glass clean remember to allow room for it in your design.

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

I would like to share some of my links with everyone. While some will help you solve some of the problems out there others may only serve as a steping stone to a final solution.


GROUND GLASS and ALTERNATVES

(Bosscreens Grainless Glass)
http://www.bromwellmarketing.com/boards.htm

(Prices for Bosscreens)
http://www.bromwellmarketing.com/prices/lenses.htm

(Ground Glass Substitutes)
http://lists.kjsl.com/pipermail/acg/2003-October/000639.html

(Bosscreens)
http://translate.google.com/translate?hl=en&sl=de&u=http://www.schoon.de/bosscreen/bosscreen.htm&prev=/search%3Fq%3DBosscreen%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26sa%3DG

(Edmunds Optics - Different Types of Ground Glass)
http://www.edmundoptics.com/IOD/Browse.cfm?catid=453





DIAOPTERS, MACROS, ACHROMATS and APOCHROMATS

(Tech Spec™ Achromatic Lenses)
http://www.edmundoptics.com/IOD/DisplayProduct.cfm?productid=1749

(Tech Spec™ Diffraction Limited Large Achromats)
http://www.edmundoptics.com/IOD/DisplayProduct.cfm?productid=1501

(Commercial Quality Positive Achromatic Lenses)
http://www.edmundoptics.com/IOD/DisplayProduct.cfm?productid=2401

(Century Optics Diopters)
http://www.centuryoptics.com/products/broadcast/achromatic_diopters/

(OptoSigma Percision Optics and Hardware)
http://www.optosigma.com/miva/merchant.mv

(Cheap/Professional Grade Achromat, doublet, triplet, prisms, etc.)
http://www.surplusshed.com/search.cfm





PRISMS and IMAGE FLIPABLE LCD's

(Tech Spec™ Schmidt Prisms)
http://www.edmundoptics.com/IOD/DisplayProduct.cfm?Productid=2430

(Technically Explaination of Different Types of Prisms)
http://www.tecplusplus.de/ManualLu/prisms.htm

(Technically Explaination of Different Types of Prisms - Website 2)
http://topcontechnotes.home.att.net/viewingsystem/page8.html

(OptoSigma Percision Optics and Hardware)
http://www.optosigma.com/miva/merchant.mv

(Dove Prism)
http://www.doveprism.com/

(Cheap/Professional Grade Achromat, doublet, triplet, prisms, etc.)
http://www.surplusshed.com/search.cfm






OTHER

(Flange Focal Distance Table)
http://www.gregssandbox.com/gtech/filmfacts/flange.htm

(C-Mount Fine Thread Focus Tube)
http://www.edmundoptics.com/IOD/DisplayProduct.cfm?productid=1678

(MovieTube - Commercial contender to P+S Technik Mini35)
http://www.movietube.com/

(Mesmerizier - Rear lens mounted anamorphic optical system)
http://www.kishoptics.com/mesmerizer-mini.html

(Relay Lens Manuel Iris)
http://www.edmundoptics.com/IOD/DisplayProduct.cfm?productid=1966

(Aspherically Contoured Fresnel Lenses)
http://www.edmundoptics.com/IOD/DisplayProduct.cfm?Productid=2039



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

<<<-- Originally posted by Agus Casse :

So, who is really working in building it ? -->>>

hi agus,

i know that all of you saw the alain project, which is marvelous.
i'm WAITING for very small GG, made by optician and he promised to make it (much) less then 3microns. everything else is prepared - pentaprism, and prism for inverting the picture.
(actually i have two different ideas with different prisms, how to solve the upside down problem, but - again i'm waiting for the parts.)

i can bet that many people are also waiting for certain parts - probably louis feng is also working on his static project...

daniel moloko is probably very busy - and there is no info from him about the proper GG from zenit...


i tested tons of different materials for GG but the grain is always visible.

i checked the HUGE range of zenits, to find grainless GG - but no succes. (zenit E, zenit B, zenit B3, zenit TTL("5"), zenit TTL ("3")... maybe there IS GG on some of that models, but i didn't find it)
i checked also "peephole" with small rounded screen, but still the same - grain!
..etc.

if i may say that each defeat leads us to the success - we are VERY close to the final stage!

keep AGUSING!!!!!
no surrender!

I've been working on a couple different designs myself, but just don't have the money to put into Doing It Right. Things do look promising, but it's slow going for me.

I've got the DVX and I'm stuck on the diopter problem. don't have the cash yet for the glass.

I'm with you Dean,
There might be some power changes to the Achromatic diopters for the DVX to be used with 35mm motion picture lenses but to use the 3.5 and 2 will work fine with still lenses...I will keep you posted or have a look at

http://www.dvxuser.com/cgi-bin/DVX/YaBB.cgi?board=news;action=display;num=1070228577;start=0

Guys i know, alot of work has been done about flipping the image with prisms etc..

But i've been thinking, and have asked my self :

Is is REALLY nesessary to flip the image?

i think that this question is really important as this will DIRECTLY effect the entire project:

Basically i think its fair to say that we/ everyone thus far have automatically ASSUMED that it was really required to flip the image in camera so to speak.

I think you guys should really re-evaluate the need for flipping as opposed to post flipping, and think about the benifits, no flipping = simpler design , fewer parts, better image quality.

I mean you gonna be editing at some point right so flipping an image in post is no worries really.

Yes, yes i know i advocated in another post iabout using security/ medical cams but thats not really practical, not for what you guys are doing anyway!


Anyway Guys, i'm sorry if this comment is not of value or constructive/ and or if this issue has all ready been raised.

Just my small view.

I agree about that- a 7" LCD that will do the flip and invert is good enough while shooting. They are about $200 or so. It would be nice to get one that is color correct and has good clarity - that might run more.

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

This might be straying a little too far out of our comfort range (I have almost no idea what they are talking about), but I found this pdf file on the web:

http://www.k-ids.or.kr/science/conference/session_A/a6.2.pdf

It's a proposal for using a lenticular lens in a rear projection television system. It seems like this is kind of what we are going for, but on a much smaller scale.

If someone can do anything with this, perhaps a lenticular lens could work?

<<<-- Originally posted by Nathanael Jackson : hey louis... you've been absent from this forum for quite a while now... how about them holographic screens?

I remember the longest time ago on the agus thread there was talk of having actual plans... seems that topic dwindled to nothing... seems like that would be the best thing to really work on to jump start some real progress again around here...

sorry, it just seems like nothing's really gone anywhere for the last 3 weeks or so -->>>

Well, there are a number of reasons why I was absent, and some are beyond my control. I'm not going into the details or making any promises, but I am going to have something to show in a couple of days, not weeks (the last part is coming, having my fingers crossed).

good for you. Hope for some solutions on the static GG

hey guys, is this thread dead?

what are you doing... any news?
louis, give us a clue...
aldu 35 is ok, but anyhow it needs image inverter, so we will back here anyday now...

filip

I agree. Currently there are two thoughts on this particular problem:

1)on board image flipable LCD screen

or

2)Pechan prism>roof pentaprism or mirror>roof pentaprism

Whatever we end up doing something HAS to be done. You just cant expect to professionally and consistantly operate a camera if you dont correct for both up and down - left and right.

Check out the other threads in "Towards a Film Look Using DV" to find out the latest

Any quick updates on the holographic diffusion? I'm really looking forward to your conclusions on this. Sorry for the impatience. Thanks.

tag