BTW I still want to see some footage from this unit with a good highquality 3ccd camera in progressive scan..

can you guys think how nice of an image you could get with this and the vx100 4:4:4 12bit mod!!!?!?!?!

@Dan:
Most people with a budget can go for a P+S mini35 or 35Pro.
Either renting or buying it.
It's an accessorie like a mattebox or followfocus.
Video people want film look, so the want things like that.
DoF is one piece of the puzzle, we all now that and talked/wrote about it for hours.
Daniel summed it up pretty good: your aiming for the prosumer market. For me, the heritage of the VX1000.
Pro's wont flip screens, they can't afford such hazzle, rather pay P+S.
Prosumers will.
I can now buy a FX1 for 2839 Euros (I would't, but that's an other discussion...)
Would I spent 1000$ for one piece of the puzzle, if I still need lights, tripod, sound, dolly or would i rather shoot full open and in telezoom...?
Or would I go to a rental house and get a bundle allready including your adaptor?
My 2c :
Price it in reach, around 500$ and a lot of prosumers will BUY it, the same people, who want their own cam, be it DVX,XL2 or FX1, rather than RENT one for a project.
Make it too expensive and still less good than the P+S, and people will either go rent the mini35 or still try to build one themselves.
Make it even more expensive and deal with the pro market and maybe the P+S legal departement.
Make it solid, inexpensive and available SOON and not only for the FX1, and you will get rewarded for all your effort.
Anyway, keep on building...

Gents,
Thank you for your feedback. You are all right (in one respect or another)
A configuration consisting A + B + C gets a patent.
A+B+ D (instead of C) will not get a patent by the doctrine of equivalents,
but an A+B will. Same for a B+C. We can not stop at one point in time,
just because someone has invented something (we would not have
electricity to type messages)
The first one I made is a basic SLR config. (lens mount, mirror, GG, prism)
Can I get a patent on that? Yes because I "shake" the GG and the
results are different.
No because P+S may have a patent.
Well, I did not find any patents here in Canada in that respect.
Go here:
http://patents1.ic.gc.ca/intro-e.html
and if you find something relevant, let me know please.
(I asked them (P+S) recently to provide the patent. I had no answer)
I will leave it here for now.

About price:

I respect your opinion. Every one of us thinks though the earning
power we have at one point or another.
Most have a burning desire but a limited budget. Same goes for
productions. Yes. Imagine a series here in Vancouver where the DP
asked me (in Sept) to "make" him an adapter for HD.
I looked at it, and (Thank heaven with Sony) did what you saw.
I never thought of the PD150 market (thanks list!)
He is fully aware of P+S PRO, used it for one day on the show and returned it to the rental house. (It was booked for a week)
No further comments.
If one would rather go for "brand" regardless the price or alternative
solution, is not my problem.

Heavy optics (that could catch dust as they did in the small one I made for GS200) ,bigger box and heavier unit all together (and bigger budget) does not suit my view.

I do what I do for that's what I believe in.

I would rather use a monitor that flips the image L-R and U-D than
carry a heavy weight all the time. (it looks like is just me here and Joel) and pay a fortune for all the optic alignments that come with it.

Great forum. Great response. Thank you.

Hi Dan,

May I ask what is your desire price target range for your device if it is not confidential?

Regards
Leigh

<<<-- Originally posted by Dan Diaconu : Gents,
I would rather use a monitor that flips the image L-R and U-D than
carry a heavy weight all the time. (it looks like is just me here and Joel) and pay a fortune for all the optic alignments that come with it.

Great forum. Great response. Thank you.
-->>>

I have a hard time believing it's just you and I that think that's a better course. I'd trade 2 stops less light loss for an inverted picture every time. Add a lower price, higher picture quality and fewer places to get dust and I really have a hard time understanding what anyone else is thinking. I suppose they are thinking they don't want to flip it post.

Or they might be thinking it's tougher to market a device that records upside down and backwards. I'd agree, but you'll just have to make your case and then point them to P&S if they want it upright. I think economics and image quality will win out EVERY time. Artists are willing to go through a hell of a lot more pain than simply flipping in post to make beautiful images they are proud to show off.

ANY monitor will work too... just flip it 180 degrees and mount. All the camera playback controls work normal for on set reviews of the shots.

I hadn't seen this design of yours before:
http://pictures.care2.com/view/2/709905811

Very slick. That's nearly as compact as the static one guys are making. I think you've really got something nice there. My advice on price would be something like this... $350-$500 for the very early adopters... say the first two weeks or first 25 purchasers. Then double the price once you've got kinks worked out and have some great testimonials.

That's not unlike what software developers do for their private beta testers. (They usually get the BETA free and then can buy the retail version for cheap) Frankly, if it was me I'd take it a step further and reimburse a few people their purchase price if they provided you great footage for your demo DVD. To me that would be a well done short or music video etc. It would probably cost a lot more for you to hire someone to do that kind of work.
See http://www.marlathemovie.com for what I think is one good example.

Killer footage is how you'll convince the larger market to buy this thing. (people around here are already sold on the concept and probably don't need to see that).

FYI, the PD-150 will require a step up ring from 58mm to 72mm. A generic one is available at BHPHOTO for $7
http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=98860&is=REG

Dan-
I watched your video for your other adapter but I think we would all love to see what the 72mm adapter can do.

Please post a FULL rez LOSSLESSLY compressed video of a pan under a high contrast enviroment. Also a static shot. Considering bandwidth issues just make the whole thing only about 5 seconds long and then set it to loop. Personally I would like to see how sharp it is. Alot of past attempts have had issues with images that were overly diffused. Alittle softness can sometimes help but too much and its simply degrading the picture quality.

I can tell you from the outside your device looks very well designed. Extremely compact and professionally finished. Im crossing my fingers that its image quality is equally impressive.

Give us a link to a full quality sample video.

Thanks for all your hard work!

I will wire you $500USD right now if you can build me one and show me some HIGH QUALITY images from the unit..I am using my "homemade" adaptor with the spinning CD-ROM motor on almost EVERY shoot I do..the image is so much better this EMBARRASSING contraption wins out OVER AND OVER again..it's like NIGHT and DAY..for me and my clients anyway ;)

I sure hope you start building them soon..put me down for the FIRST unit you make

I do hope you have dealt with the issues of alignment of all the parts so the images are SHARP and in focus from top to bottom and left to right..I know this is a problem with my homemade unit ;)..but yours is machine CNC made right?

Gents,

I am overwhelmed by your response on this forum
(and private emails I received)

Brett, you're either a hell of a psychologist or simply honestly impressed, but you managed to touch my sensitive
cord (my stupid pride that is!) to have my work recognized.
You too Obin!

I have dealt with misalignments L/R and U/D in Sept and
took care of in the latest design to be "foolproof" for assembly
(no adjustments needed, one way only is the right way)
But I hear full well what you are saying..........
Bin there (lol)

Sharpness wise is as good as the lens in front. I hope in the next months to print on 35mm film (MP)
the image captured using the last device and shooting
Sony HD FX1 (to make a point again) I intend to use Zeiss superspeed, (just to get any guess out of the way)

I might have to disappoint you Obin, but there are three
hungry "wolves" howling outside my door ....and waiting
for me to get out.
I want to get on the set they shoot (a series that started 3 weeks ago and ends in April)
and shoot some footage. Than I do not have to bother
with lights and "set-up"s, the talent is there, and the time is 1749 in Paris. (I should make something out of it)
That's about footage.

In terms of shipment, it will be a while (hopefully end of January) (I am working on it!)
I can not afford the time to do it myself. It is a lot of work
and time is money. I did enough (for now)

I have a few priorities:
I am working on getting a website up and running.
Footage will be posted (as it comes), pictures of the device,
feedback from customers (unedited)
I intend to add footage to the site from you guys as
testimonials and give a price for the most beautiful
cinematographic work. (we all win after all)

This new site is intended as an open forum for exchanging ideas and work experience. (I have learned this trick from Sherline, and I think is GREAT):

They build the basic lathe, milling machine and quite a few
accessories. BUT, if you look at "tips from other machinists"

http://www.sherline.com/tips.htm

you will find a lot of "clever gadgets" made on their lathes
to help them "work" easier/better ..... on the lathe.
Sherline does not make them. Amazing.
They have it all on the website, but not offer them.
Why?
Because whoever wants one, has everything they need to
.......make one.
But simply sharing the knowledge is just fantastic.
That is a good example to follow.

And now.....
the "money shoot" ;

Help!

I have a very hard time to figure out what to do about the
mount(s) for the SLR lens.
Many of us have a big collection of wonderful manual lenses
from different manufacturers. Minolta, Nikon, Canon.
They all work just great.

Ok, ok but what do I do?
Do I put a mount on the "darn thing" or do I leave it to you and pass on the savings (cost of parts and assembly work?)

I did some 23 years ago a blow up of a 35mm color neg to
50/60 cm until I saw the grain from the film. But the lens
was good enough to show it!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
(Canon 1.4/50 and a "decent" (no name) enlarger lens.

If is Nikon or Contax, or any other brand, I assure you it will be hard to tell the dif. On a 52" display they should not show any weaknesses.

There is too much of other stuff to
"look after" ;lights, highlights, shadows, white balance, etc,
that the sharpness will be there anyway (if properly focused.
And here is another point. You might consider a focus
puller. When set in motion, the operator can not afford to
look like he left the focus on AF (hunting for the sharpest
image)........while the talent cries their eyes out delivering
the performance of their life. Whoa..........
Got some work to do here and got carried away.
Thanks again.
Soon.

<<<-- Originally posted by Dan Diaconu : Gents,

I have a very hard time to figure out what to do about the
mount(s) for the SLR lens.
Many of us have a big collection of wonderful manual lenses
from different manufacturers. Minolta, Nikon, Canon.
They all work just great.

Ok, ok but what do I do?
-->>>

You could go with a t-mount adapter and then everyone could buy the matching adapter that they need for their lens.

Or go with Nikon as the first mount. I know there are a lot of good old lenses out there, but my guess is that Nikon is the best blend of quality/availability/affordability

I may be the wrong person offering advice, here. Having read that the image will be upside down and that this won't really work with an XL2 (seeing how it will have to hang onto the end of my lens somehow and my viewfinder image will be upside down), I think you're shooting down the idea of charging anything more than $500.

From a marketing standpoint, I don't think you can compare this to the Mini35, because it's in a completely different league. Like I said before, your target market will be the 'hobbyist'. The 'gorilla-style film maker' (that's not meant in a derogatory way). Then again, will they even have $500 in their budget? Don't know. Rather than how much it's worth to you, you should consider how much your 'potential customer' can afford to pay for it. Does that make sense? Weigh each aspect of the unit. For example, you may have spent 5 months figuring out how to replicate the ground-glass movement ... but the unit is still a homemade-looking contraption that makes noise and gives you an upside-down picture. What about lens mounts? Is the groundglass guaranteed to be in absolute focus? What if someone needs to use filters? I'm not looking for answers to these questions ... these are just points you need to consider yourself.

One thing you're got going against you is the fact that the Mini35 with rods, handles, mount and follow-focus unit rents for $250 per day. Like I said before, I may be a bad person to give advice because I'm more in the prosumer to pro market sector.

Just a note - you may be able to have a machine or metal shop design a professional housing ... to give it a more professional look. I have things made by machine shops all the time and it's rather reasonably priced!

Joel beat me to it. Go with the T-Mount and then either we could buy our own lens T- mount adapter or you could include one of a few choices with it. P+S Technik sells them seperately but then again they are custom made for the Mini35. I'd recomend you include the right T-Mount adapter according to each order. Throw it in a seperate box if need be. You want to give your customer the closest thing to a out of the box device to make them happy. You dont need to have T-Mount adapters for ALL the different companies out there. Just 3 or 4 of the major players. Anything else the customer can get at B&H.

Look forward to seeing that video. Only then will I personally beable to give you a accurate number as to how much I would be willing to pay.

<<<
From a marketing standpoint, I don't think you can compare this to the Mini35, because it's in a completely different league. -->>>

Here's the way I see it. I don't give a ratsbehind what the unit LOOKS like as long as it's fairly compact.

In this case, I think both his devices look BETTER than the mini35. Plus you can slap it right on a DVX100 which is probably the biggest market for this thing right NOW. He may need to add a rod system to help support large lenses.

But with a smaller lens:
http://pictures.care2.com/view/2/717325749

VS. this mess?
http://www.pstechnik.de/datasheets/pics/digital/d_mini35_2_l.htm

The Mini35 is ridiculous on any camera other than an XL2 (one of the sillier looking cameras ever produced in it's own right)

Having said that, there's a guy on another thread that put a static adapter on the front of his XL2 and seems to like it. So that CAN be done TOO. I think Dan's unit is more likely to turn an "on the fence" XL2 buyer into a DVX100 or Sony FX1 / HVR-Z1U buyer.

Additionally you could adapt to a zillion other cameras with inexpensive step up rings. There are some pretty nice under $1k 3 chip cameras out there right now. Great for pre-production trial footage. Remember, that was supposed to be one of the Mini35’s selling points? If it’s not the final product then all it has to be is “good enough”. Does anyone really use these for trial footage though?

Nothing in Dan's posts indicated his unit makes much noise. I thought he specifically mentioned it was very quiet. If it's really noisy that might knock it out. Or I might baffle it because the unit is so compact.

As to renting a Mini35... great if you're in LA or NY go for it. I'm in Phoenix... the 5th largest city and there isn't ONE for rent. So, taking a wild guess here... that probably leaves about 90% of the world's population without a Mini35 available locally to rent. And if 2 days rental BUYS one of Dan's then I feel sorry for the rental houses anywhere other than LA.

In the end it comes down to image quality. If his image quality is as good as a Mini35 or better for a fraction of the price it will sell just fine. If the image quality is too soft it won't sell for $19.95 even if it includes 3 extra knives. ;-)

As to the higher end market... the Mini35 will be either put into obsolescence by units like this one (buy 10 instead of one and do multicam shoots) OR more likely it will be killed from above. The new small company brew HD cameras will drop into the 10 to 25K range like the Drake system. I'll be looking very seriously at those when they happen.

It's safe to say my opinion is the Mini35 is close to dead at it's PRICE at this TIME and there's much more of a market for a low cost unit. Then in 5 years technology may erase that market.

Thank you Joel for your sincere opinion and fare vision.

Noise, image quality, size, weight, compactness, all have been
extensively considered and will be documented soon on the new site
(a rods support for longer lenses and T-mount will be there for all)

(I can not resist though): If anyone will EVER (that's a STRONG statement)
find any better image converter using a GG in motion
(brighter, less noise, less blah blah, etc AND no grain visible not even when the aperture on the SLR lens is set at
16 !!!!!!!!!!!!!!!!!!

HELO!

16!

hence a crispier picture, emulated by another device, you will prove me worthless.
(of course using a different method than mine)
The pictshaaaa is as sharp as the SLR lens can deliver @1.4 or 1.2. (Clips soon)

Keep in mind, please that my drive on this quest was FX1 print on film, for theatrical distribution. That defines a certain market segment.
Can't compromise anything with THAT goal in mind.

Please note that for the Pro35, P+S recommends using apertures no higher then 4-5.6.!!!!!!!!to avoid seeing the grain of GG. Anyone with me?
The unit is $ 28.000 US. Twenty eight thousand.
(have to catch my breath.....huh, that's better now)

I live to set standards, from which (hopefully) all measure.
Been doing it ever since. (this is how I ended up having as many friends as I have........)

Performance. That's all I care and live for. The best that can be achieved. Can I do it better than I did it yesterday?
Am I better than I was yesterday? It will end in the grave. Then I will be perfect and everyone else happy.
(if I was around for money, I would have done something else by now, without irritating everyone ....)

End note:
I already thought of another way to reduce the noise further. (further improvement on the current movement and no mousepads involved)
Dono if I will implement it though.
Too expensive to assemble. But..... I'll think about it...............

<<<--
Originally posted by Dan Diaconu : Thank you Joel for your sincere opinion and fare vision.
->>>

Hey no problem. Now buckle down and put a couple together so Obin and I can be the first couple of guinea pigs! Provide us with an upgrade path of course. :-)

No offense, but you're not the first (or 2nd) person to come around here saying you were "this close" to having something people could buy/replicate. I think you're closer than anyone else from what I've seen so I'm hopeful you'll pull it off.

There is one other thing I wondered about your design. Can the battery be replaced if it runs down while on location?

I use NiMH rechargeable. They should last for about 100 hours of continuous use on one charge.
(They last longer than that but I am playing on the safe side)
How many hours or takes or days that means?..... depends on the shooting style. Unless you forget it ON (LOL)
One should have enough time (once a week) to leave them for one hour plugged in.

Too much talking, not enough action. Why not show some side-by-side comparison footage, rather than writing a novel about how great the picture is (and how much you love yourself)? I hope Dan's unit takes off and becomes competition for the Mini35. But I doubt it will. At this point, I kind of get the feeling that Dan is looking for compliments from this board, more than input and ideas to develop his unit.

It just seems that Dan's writing about how great he thinks he is and how great the picture is and how some huge producer quickly returned a Pro35 when he got Dan's homemade contraption ... and the 2 guys on here are blindly sucking down what's being fed to them - without seeing any proof.

Show some side-by-side comparison footage, prove me wrong. Then, if the picture quality really is comparable (or half as good as you rant it is), then you'll need someone to design a professional-looking housing. Then you'll have something.

About renting the Mini35 in other cities - you have it shipped. Most suppliers don't charge for delivery time. I live in the DC area and we don't even have one to rent.

<<<--
Originally posted by Daniel Stone : Too much talking
-->>>

You're right. I think your objections have been noted.

I do think some uncompressed footage like Brett requested is called for soon but I don't think Dan needs to spend a nickel on redesigning the housing. I'm with Brett on that one too. It looks well designed. Certainly better than the Mini35 hackjob. (sorry, couldn't resist - but it does look like a joke afterthought on a PD-150 or DVX100).

Dan Im going to have to agree with Daniel. Your ego needs even more stroking than mine. Show us the goods.

If the sharpness isnt there then thats that. We can always go with my design which works with medium format lenses and a much much larger (clearer?) image on the GG.

See there is always a better design right around the corner so try and keep your comments under control.

We all look forward to seeing the videos.

<<<-- Originally posted by Brett Erskine : Dan Im going to have to agree with Daniel. Your ego needs even more stroking than mine. Show us the goods.

If the sharpness isnt there then thats that. We can always go with my design which works with medium format lenses and a much much larger (clearer?) image on the GG.

See there is always a better design right around the corner so try and keep your comments under control.

We all look forward to seeing the videos. -->>>

Hi Brett,

Can you direct me to your url which you are talking about in your post? I am interested to know about your design.

Regards
Leigh

Unfortunately I dont have a website dedicated to my design. Actually its basically P+S Technik's design but with a 645 medium format GG. But if you want to read more about the advantages of using large GG and MF lenses we extensively talked about it in:

http://www.dvinfo.net/conf/showthread.php?s=&postid=254002#post254002

But this is Dan's thread so I dont want to cluter it with other info. Dan's adapter is much further along than mine and I applaud him for all his hard work. In reality we dont know which one is better and it was unfair for me to say so without knowing for sure. I was making a blanket statement based on the general fact that the imperfections of GG are all reduced when the image is larger as it would be if it used medium format lenses. Even Dan's adapter will be even clearer if it used MF lenses. But perhaps its clear enough already. So my apologies and I take back that particular statement.

I don't think you have to post uncompressed video. At SD res I think you will find 10 megabit/sec media 9 videos will preserve all the grain or lack there of. I used a bit less than that for 720 P and it holds up well. Well enough for HD dvd's too, the industry shows. Take the T2 special edition for example.
So how about a media 9 vid!
-Les

Brett.

Off-topic. The camera tech who showed me the dove prism also asked me why I was using 35mm still cam lenses when medium format would be so much better.
(He has a store full of medium format stuff he wants to move of course but he made the same point as you do. If one wants HD resolution then one must use the scaling effect of a larger format and gg screen area to reduce the grain proportionately, also the inherently better resolution of the larger format).

Medium format does seem very promising Bob - even with the slightly slower lenses.

How much light do you loose with your system Dan?

No hard feelings,
just hard work.
Use the camera (camcorder)you have, aim at a scene and take a reading (ex: 1/60 5.6)
place a lens and a focusing screen of an SLR infront and take another
reading. ( It doesn't show a loss over 1/3 stop or less here)

Check out my link for more info but heres a quick overview:

Expect MOST MF lenses not to open more than f2.8 while in 35mm most lenses open up to around f1.8-2.0. There are special cases for both formats of coarse but these are generally what your going to get in the affordable lenses.

Now I know what your thinking...MF lenses sound like they are up to 2 stops slower than 35mm lenses. Why would someone want to use them...? Well consider this. Because the image they produce on the GG is so much larger you wont have to zoom in with your video cameras lens to see it full frame. And as many of you know if you zoom in on most video camera lenses you start losing stops (ie DVX100 is only a f2.8 at full zoom and a f1.7 at fully wide). So if you dont have to zoom in you just gained back any light loss in the system. Basically your in the same boat in that sense so no additional light loss problems.

Next DOF. DOF is even shallower in MF versus 35mm. The DOF of a MF lens set at f2.8 will be very similar to that of a 35mm lens set at f1.8. So once again no problem there.

Now on to the advantages. Since your no longer trying to capture such a small image on the GG you dont need a diopter anymore. Anyone thats been experimenting with diopters knows that the inexpensive ones have major color fringing problems that severely effect the final image quality. While the achromat diopters work much better but one thats both strong enough and of high enough quality are very expensive. So with a MF DOF adapter you no longer need a diopter. One less piece of glass to worry about.

Next because you have a larger image on the GG in MF you can expect to see a increase in clarity and a image thats less diffused.

Once again Dan's adapter might already be clear and sharp enough so all of this might not be necessary. But if it isnt, I personally feel he can improve his incredible adapter even more by switching to MF lenses. Thru building many versions of a 35mm adapter and watching the footage posted by others online its been my experience that the footage has always been overly soft. To the point its draws attention to itself and wide shots loss some important detail. Try shooting the same shot with and without your adapter to see what Im talking about.

Anyways this is one way to get around that problem but I also believe with enough searching its possible to find right type of GG with characteristics that would allow someone to pull a pretty sharp image out of a 35mm adapter. Look at P+S Technik. They look pretty good. Not perfect but close.

Anyways something for everyone to consider.

<<<-- Originally posted by Dan Diaconu : No hard feelings,
just hard work.
Use the camera (camcorder)you have, aim at a scene and take a reading (ex: 1/60 5.6)
place a lens and a focusing screen of an SLR infront and take another
reading. ( It doesn't show a loss over 1/3 stop or less here) -->>>

No offense,

Show me the real demo.

<<<--
Originally posted by Brett Erskine :
MF - Anyways something for everyone to consider.
-->>>

I know I got pretty excited when I pointed my camera at my Mamiya RB67 GG the first time. I ordered some satinsnowglass gg in that size so I could try it out. I still had vignetting and grain issues though the images did show some real promise.

You may be right, Dan's design with a MF lens and bigger GG might be the ultimate... especially when moving towards HD.

If systems like the Kinetta get cheap enough it may be moot. You can slap a 35mm lens right on those.
http://www.kinetta.com/download/files/kinetta-camera-brochure.pdf

About the preivious "method" to determine the light loss:
Sorry, I did not express the test clearly:

The 1/60 @ 5.6 (or anything else suitable for the avail light) I was ref. to, was the reading on the camcorder /digital still.
The lens I used (and did not see much light loss) was Nikon
1.4/35 and Minolta 1.4/50 projecting the same scene image on the GG.
Camcorder zoom matched the focal lenght of the SLR lens, in both cases.
(so the same amount of reflective light from the same scene
would be compared) : direct reading vs. 1.4/50 lens on the GG.
I am sure a light meter would be more accurate in reading,
but I did not care to find out the actual loss since I do not know of anything brighter than Beattie.

A holographic diffuser

http://www.globalspec.com/featuredproducts/detail?exhibitId=3781&fromSpotlight=1&fromSupplier=0
http://silver.neep.wisc.edu/~lakes/HoDifLoScat.pdf
http://www.poc.com/lsd/default.asp?page=applications&sub=hdst
http://www.photonics.com/spectra/applications/XQ/ASP/aoaid.313/QX/read.htm

As far as I understand from the above (and other sources)
this is (in simple words) a "linear" Fresnel, used in LCD screens (and other applications) to even out the light from the
(usually two on the sides) light sources found in LCD's.
The light loss (towards the center of the screen with the square distance from the sources)
is precisely matched and compensated by the amount of
reflective surface: the further away from the source, the
bigger the reflecting receiving tip of the prism. End result;
evenly reflected light of a surface from the same linear source.
Did not try them, but I do not envision them transmitting more light
(from a centered light source such as lens) towards corners than the same thing
made specifically for the purpose (such as Fresnel in Beattie screens)

If you find them brighter, side by side measured, let us know.

PS. Same idea used here
http://pictures.care2.com/view/2/836676796
to even out the screen (from 3 LED's) of a "bomb detonating watch"

Merry X-mass, Happy hanukkah and
a happy new year to all members and guests.
(better later then never, I guess...)

Dan,

Unfortunately I do not have a beattie screen to run tests with.

Holographic diffusers can have a trasmittance greater than 90%. I would be very surprised if any GG or screen could match that.

I'm not entirely sure what you mean by a "linear fresnel" but these diffusers produce a highly homogenized light ouput. The direction of the initial lighting is not important. In addition to this you can use these diffusers to redirect the light in numerous directions and shapes. Very cool stuff!

From the POC website (the company who holds the patent):

"Light Shaping Diffusers are holographically recorded, randomized surface relief stuctures that enable High Transmission Efficiency (up to 92%), and Controlled Angular Distribution, while providing high quality Homogenized Light. These fully randomized (non-periodic) structures are non-wavelength dependent and will eliminate moiré, without chromatic aberration. The precise surface relief structures provide controlled angular light divergence, emulating a negative lens.

Standard and custom OEM products are available, including a variety of angles, sizes, shapes, cut-to-print parts, and substrate materials including 2-sided diffusers (PCS), variable angles, color tints, and low birefringent substrates."

Aaron,

I am just as curious as you are to find out the dif (I am sure there is
a BIG one)
Do you get a "hot spot" in the centre? (using a wide 20-28mm lens)
on a 24/36mm surface? (I would be surprised if you would not)

poc site
 

Aaron,

i checked poc site:

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

and read what you already mentioned. did you chcecked that more deeply? i'm not expert on this - but which one diffuser is sutable for our GG works - in your opinion? any of the mentioned there on their site, or it shlould be custom made?

thank you,

filip

Dan,

I don't know if there is a big difference or not. It would be great to find out but I just don't have the necessary supplies. I'm not here to say that beattie screens are worst than holographic diffusers so you have to go with one or the other. I'm just passing on some interesting knowledge I've gathered.

From an online article regarding holographic diffusers:

http://www.mdatechnology.net/techsea...p?articleid=33

"The holographic beam homogenizer is a thin sheet of material that diffuses light. Placed between a light source and a display, surface, or screen, the homogenizer eliminates “hot spots” (bright concentrations of light) and dark areas, improves transmission efficiency, and redirects light"

Filip,

I'm not sure what would be best. I'm not an expert in this area either. From what I have gathered though I think what we want is a low angular dispersion (less than 10 perent if possible). For 35mm lenses you could probably use their 50mm rimg-mounted diffusers. The other option would be to buy one of their rectangular sheets.

For me, since I am interested in using MF lenses, the 50mm will be too small an imaging surface. I'm going to have to purchase one of their larger sheets. What's great though is that these can be manufactured to anamorphically squeeze the image for you! No need for ANY lens!

I am "digging" into this matter. I will let you know if I find out anything of interest.
Did you check the tech info from beattie?
How they make the difuser and the Fresnel?
Just in case you missed it, it's here:
http://www.intenscreen.com/pdf/focusing_screens.PDF

I am no biased in any way and ready anytime to switch for
better (providing it can be demonstrated to be better for the purpose!!)

Very interesting Dan. I can't tell precisely how or what the screen is made of from that PDF. It seems to be a fresnel made with holographic processes? Interesting...

Anyway, I'm going to be getting a holographic diffuser to play around with so I'll post when I have some results.

yes, let us see some pics.

Okay guys heres the low down on all of these diffusers your mentioning. Sadly I've been posting on this project since the very begining so I've heard all of these diffusers being tested for this purpose. (According to what was posted):

Holographic Diffusers are simply diffusers that have highly diffused characteristics. By doing so they create a image that is unlikely to create a hotspot because light is diffused at a much wider and even angle than traditional ground glass. This is good when it comes to getting rid of the hot spot BUT this also creates a problem. Since the light is going in all directions only a small portion of it is actually directed towards the CCDs. This means the image is much darker than traditional GG. Not good. Now they come in different versions with some less diffused than others but it was determined even the brightest wasnt nearly as bright as GG.

Beattie screens are regarded by most photographers as the brightest screens. I've tested them and they are indeed bright but there is another much smaller company out there that makes screens that people swear by. The company is called Maxwell Precision Optics. Thoughs that have owned both Maxwell and the Beattie insist that the Maxwell screens are even brighter. I've tried them both out but never side by side. I own a Maxwell and I'm happy with it. The reason the Maxwell may perform better is the fact that the fresnel lens is both finer and can be ordered to match a given focal length. In other words you can get one that can be perfectly calibrated to your system. No hot spot, bright and fine fresnel lens. However the company is so small they dont even have a website. I did a search for it to find the address and phone number. The owner is a Bill Maxwell and a incredibly knowledgeable guy when it comes to optics. Thoughs thinking about using it for a static adapter might want to keep looking though because while the grain is small isnt not too small that you cant see it. And if you are making it oscillate it better be a very very small movement because you have to remember once you make the PCX lens (fresnel) and the GG one they are forced to move together thus their focal point moves as well. If it moves too far off center of the CCD you'll get a hot spot again.

If you are looking for a focusing screen that is as grainless as they get look at the laser etch screens in the new pro model Canon EOS bodies. They are incredible BUT (dont you hate that?) they dont make them without markings. Find a way to get it without markings and I'd think you'd be in business.

Brett Erskine

Brett,

Thanks for passing this one by.

I did not know of Maxwell (I knew there were others) but did
not bother to look them all up front. One of the best is good enough for a "proof of concept".

(from what I know, Beattie also can do custom focal lenght on the Fresnel, but that is a lot of money)

About contrast.
When I first ordered from them, I specifically requested a bright but low contrast screen (or if they can make one) Tough luck.
Reason: a lower contrast would act as a better "translator" between real life contrast ratio (sometimes as high as 14 stops) and the CCD's limited range. (less than film anyway) I hope this helps.
That awfull hi-contrast (aside from huge DOF) makes video look as it does.

Just a thought for the non moving concept. If the image form
the grainless GG is good enough on a 50" plasma (and it doesn't show any patern) than that might be the solution.
(although some might be tempted to print on film (for theatre) from HD )
Well.....looks like we can't have it all.