dear Bret..correct me if im wrong but the "beatie screen w/ grids..custom mills etc.".. you were refering to me? (dogus not dino?)

bret i would be happy to send you prices and the mills..please drop me a mail at dosealas at tumgorsel dot com.. the beatie screen with grids of course has effect on the final result...i used that screen for testing purposes only..as i found there is a great difference in image quality between the medium and high format..i have made a great research on fresnel lenses..and i have come to this conclusion...when light hits the gg the image is diffused to every direction..light passes through the slr lens and on to the gg...the light enterinng the slr lens comes from all directions also but the light amount that passes paralel to the lens is much more than light rays that go through the lens non-paralel..since thouse non-paralel rays hit the inside on the slr more and dont find their way out..this results as the image being brighter in the middle and dark on the outside .. the fresnel lens has the property of changing the direction of light rays (paralel and non-paralel) to the paralel path...so theoreticaly there should not be any heterogenese light..but this is theoretical and has not been tested yet.. i hope to be testing in this week..(i have final exams in a few weeks and i dont know if i will find the time)..but i have tested on other gg's for i am ready for such a fault in the fresnel lenses..but i must admit the fresnel gg has very low light loss..which is really amazing when compared to ordinary gg..in my experience plastic and glass too differ..the few plastics i have tested all had very low light transmition compared with glass..and even 4mm glass compared to 1.5 mm glass gives a great difference in f-stop values..i think if the beaties screens give results as you mentioned...the step i will take to get over this issue will be your way.

bret what was the gg with fresnel you used?yes i am still studing on this project and i would love to read more about the custom calibrated medium formats.

les can you also send me a link of your work and images..

dino i have not considered any kind of motor yet..i want to first assemble the parts and then see how much power is needed..i have talked with a remote control helicopter freek who makes his own helicopters..we have gone together through the subject and we have left enough space covering a wide range of motors in the design..

Dogus-
Yeah sorry I was thinking Dogus and typed Dino. As far as the issue with the fresnel lens. Its pretty easy to see the problem. Simply hold the screen in front of the lens your planing on using and move it around a few mm by hand. You'll see it.

The calibrated focusing screens I was talking about are the Maxwell screens. They come in all sizes and focal lengths. The fresnel is made up of tighter/sharper groves then even the Beatie screen. They are reguarded by many medium format photographers as the best out there yet many dont know about them because I believe you can only get them thru Maxwell Precision Optics. Keep in mind though that these are one piece fresnel/gg screens so unless you find some way to get over the issue above they will be useless. However they will work great for the people designing static mini35 adapters.

Anyways the email is on the way.

hi Dogus do you think your machinist. could make a smaller version of the eccentric shaft . 5mm or 6mm ?

yes i suppose he can make them aswell as long as you send a detailed plan of the mills you want..

thank you dogus. the plan is to use this parts list

1http://www.thorlabs.com/ProductDetail.cfm?DID=6&ObjectGroup_ID=60&Product_ID=11138

2http://www.vxb.com/miva/merchant.mv?Screen=PROD&Store_Code=VXB+Bearings&Product_Code=Kit%23688&Category_Code=6mm

3 this will be a link to a 6mm eccentric shaft

4http://www.thorlabs.com/ProductDetail.cfm?DID=6&ObjectGroup_ID=956&Product_ID=1018

5 http://www.thorlabs.com/ProductDetail.cfm?DID=6&ObjectGroup_ID=1132&Product_ID=36109

6 http://www.thorlabs.com/ProductDetail.cfm?DID=6&ObjectGroup_ID=213&Product_ID=1480

the basic plan is 3 cage plates drilled out to fit 10mm od ball bearings. fit bearings in 2 cage plates . (4) 6mm eccentric shafts fitted in the two cage plates. about a 2" by 2" plate with lens holder nested in the middle of the plate; fitted on6mm holes in plate

third cage plate with 1 inch tube ajusted focal length . next c-mount to slr lens

i think i put it in wrong words..i ment cad plan..this is an example of my old design...

http://www.tumgorsel.com/dosealas/dodo35/cadfile.jpg

i can get you custom made mills if u send a plan like this:)

by the way i received my plates.!!!

http://www.tumgorsel.com/dosealas/dodo35/cutplates.jpg

Dogus-
Did you have all thoughs parts professionally custom made? What was the total cost?

Alright...

Got my Thorlabs parts today. They are VERY LIGHT :O

Oddly, the externally threaded coupler -- listed as an accessory to the 2" tubing -- doesn't fit the 2" tubing. I'm frankly baffled as to why this is, or how you'd use the thing at all -- the threading is the exact diameter of the 2" tubing, not smaller, so you can't insert it into the tube :(

The "adjustable focus" piece isn't as elegant as I would have liked, but it will work -- I figured the adjustments would be made just as you make focal adjustments on a lens, by rotating an implement, it would advance or recede. Instead, it's just a threaded tube that you screw in or out of the 2" tubing, that has a locking ring. Not elegant, but hey, it works.

Otherwise -- 49mm UV glass ought to fit perfectly inside the tubing (haven't had time to test this yet), though any 49mm stepdown will not work with the 2" tubing -- I'm hoping a 58mm-52mm stepdown will work properly with the Century Optics achromat, but will not have the time to test this hope out for another couple of days.

Blah -- typing this quickly before leaving for a relative's b-day bash -- sorry for the typos and other grammatical weirdnesses :D

- jim

yes brett..all except the c-mount for the pentax slr lens..strangley when i made my first design.the parts had a thickness of 4 and 3 mm's..it cost me around 90 dollars...i paid that amount..and then we found faults and bad engineering in the design (too heavy)...so i took it from the beginning used 1mm thickness and strangly it cost 40 dollars..i dont know why there was such a price change...if it would have been the 40 dollar first and then the 90 i would have asked:)...they are cut on a laser metal cutter..they are really heavy industrial machines ( i heard the purchase price for such a machine was around 1 million $ ??? ) , but my designer had worked with the place before so i could get this stuff done in such a short time...i live in izmir,Turkey.. and i heard there was about a dozen of these machines in my city..i bet there should be more in cities in europe..if anybody gets the chance..could they inform me on the costs for such parts (as can be seen here " http://www.tumgorsel.com/dosealas/dodo35/cutplates.jpg " )

i have done a test setup with the parts..the laser cutter is so presise that the bearing need to be hammered on the plates to get them in (thats what the guy operating the lasercutter told me to do) you cant get them in bare hand..i am happy with them..tommorrow we will weld a few parts..through some paint on..i have a few parts still missing so i think the final product (without the motor ) will be running (by hand that is..or using as stable gg ) in 2-3 days..

Dogus-
Izmir, Turkey huh. Some great sites out there. I was out there earlier this year shooting Ephesus and went on to Istanbul and Antalya. One of my favorite shoots was some aerials in Capadocia. Heres the footage>
http://www.cinematographerreels.com/gorematurkeymov.htm
Anyways Im very impressed with your setup. Let me know if I can help you in any way. What brand film lens are you planning on using? What format size (645?) Since we are both doing medium format adapters lets exchange info to make this work. Do me a favor and measure your flange focal length and the distance between the CCD plane and the GG. I'll run it by the optical engineer and see if I can get you the specs from the proper plano convex field lens(es).

I received my GG from Satin Snow Glass the other day. I must say that its extremely fine grained - finer than anything that I was able to do by hand. The only thing I can say against it is they are made of glass instead of plastic which means they are heavier. This might cause a excessive amount of vibrations when put in motion.

yes i had seen your footage before..real nice pal!!..

i am using a pentax 1.1.2 lense..actually its a 35mm stand format lense..i got it for around 100$..this project has flew higher than the budget i targeted along time now!:) ..but changing the lense is so simple as i have designed it so it is open for later modification.you can see in the cad drawings..i have a sony trv-940 and the damn thing can focus to a subject nearly touching the camera ..but it does make lighting issues since the object is blocking the light, so i used a transparent object..and calculated that the camera and the gg have about 1-2 cm distance..it can focus easiliy..but the closer it is the biðgger the image will be without the using of macro lenses...but i cant answer your question in terms of distance between ccd and gg..dont know how to? the distance between the lens and gg have a measure between 4-5 cm ..i have desiged the system with a distance of 4.5 cm i will pull an infinite focus and than adjust it aquaretly..the gg can move 5mm nearer or closer to the lense by screws which will be tighting the bearings..

brett i think glass will pay off because plastic has to be really high quality to satify the quality glass gives..


i am also interested in the snow glass..can you send a few images of it with an image projected...

oops..about the message i sent before..the price was for the metal parts only..the mills cost about 30 dollars each..i paid 4-5 dollars to get the srounding metal plates rounded..and another 15 dollars for the custom 37mm screw for the trv..

I was looking at your design and Im alittle curious what your planning to do for a few things:

1)How do you plan on fixing the bearings to their coresponding plates? You mentioned that its a tight fit right now but from your diagrams it looks like frictions the only thing holding them in place. Are you going to spot weld the bearings to the plate or use some other hardware to tighten them to each other? The reason why I ask is because it seems like vibration could eventually make the bearings pop out of their plates they way it appears in your diagram.

2)How are you mounting the GG plate to the oscillating shaft and then securing it?

Personally I came over these two issues by using a oscillating shaft that was threaded. This way I can use lock washers and small bolts to tighten down on the bearings from both sides and keep everything in place and solid. It also keep the shaft from spinning inside the bearing.

brett : regarding the shaft you are looking for, how long does it need to be . and what would the diameter be

brett..

1- my designer told me that the bearing had to be hammered in position..he mentioned welding the bearing would damage them..but he also added that spot welding might work..i think i will have to ask a few people...i let you know when i find out..

2- yep i have the same thing in mind.. my new mills will be ready tommorrow..except for the place where the rubber bands will be..i will put up a picture..

and brett about the snow screen..i sent an email but it returned as no such mail..can u give me a contact..

Richard-
I have some extremely tiny bearings that I bought so that tolerances would be real tight but if you have a great source for offset shafts I'd be willing to find new bearings to match whatever you can offer. If you got something by all means send me the info. Thanks.

Dogus-
Here you go: BErskine@mail.com
The mail box is getting pretty full again so let me know if your going to send a larger file.

oops:) brett i ment i mailed to the satin snow people and i recevied no answer..who did u mail...

sorry about the confusement pal:)

I called. Heres their site:
http://www.satinsnowglass.com/index.html

Hi Jim
I was wondering if you were able to do any more tests with your new Thorlab parts. Particularly the issue of what stepdown ring fits the threads.

Did you or Richard also order some of their 1500 grit ground glass? I'm likely placing my order next week and was wondering if the glass would be worth adding to it. The finest AO I've been able to find here is 1000 so I'm assuming that the 1500 would be even better.

Thanks for sharing

Jon

P.S. Congrats Dogus, your setup looks great!

The stepdown is 52mm from whatever your original lens is. For my GL-1 it's 58-52mm.

The glass for inside -- if you want to use something cheap -- should be 49mm UV filters. You have to keep the ring on and it fits fine -- with the glass alone it's a bit small, but anything larger probably won't fit.

- jim

Thought you guys might like this multi format DOF comparison.

To give you a true sense of what each format will give you in terms of DOF I've kept the FOV the same and the distance between the camera and actor the same - thus different focal lengths between formats. I also used real world lenses commonly available for each format which explains the different minimum f/stops used. For the following comparison an actor is placed 10 ft from the cameras postion. The camera is never moved nor is the FOV changed. I choose a common composition - in this case a medium/CU shot (mid chest to top of head) of the actor. Here are the focal lengths and DOF of available lens in each format:

Medium Format (645) - 200mm(FL)/f2.8 = 2.07inches(DOF)
35mm (Still Camera) - 135mm(FL)/f2.0 = 1.92inches(DOF)
35mm (Motion Cam) - 85mm(FL)/f1.3 = 3.62inches(DOF)
16mm (Super 16) - 50mm(FL)/f1.3 = 6.31inches(DOF)
2/3" (CCD Video Cam) - 35mm(FL)/f2.0 = 2ft, 2inches(DOF)
1/3" (CCD Video Cam) - 18mm(FL)/f1.7 = 3ft, 4inches(DOF)

Again the reason why their are different FL for each format is because they all give the same FOV from the same subject distance so in other words they are the same equivalent lens for its format.

Medium format image size/gg is 2.7X larger than 35mm (Still)

Brett:

Just want to clarify something--your 35mm and 16mm numbers seems to be off, but that's probably something to do with the different formats available within those gauges. Were you using a calculator based on field of view? If so, this is a horizontal measurement, but the vertical height of the frame is more relevant when considering a shot of an person (i.e. mid chest to top of head). As an example, standard 16mm and Super 16mm frames have the same height, but the Super 16 has a greater horizontal field of view.

Nominally, the difference between 35mm and 16mm should be a factor of .5x.

Yeah thats exactly right. I was basing my FOV on a 35mm 1:66 frame since it was the closest to all the other formats. I knew that everyone has their preferance between full screen, 16X9, 1.85 and 2.39 so I decided to try and keep the horizontal FOV the constant in each example but you right the important thing here is the vertical FOV because we are talking about shooting actors. If however you keep everything pretty much a 1:66 ratio for each format then these numbers should give you a pretty good idea of the DOF for each. If you would like to post the exact numbers by all means please do.

Good morning everybody.

I am the owner and producer of Satin Snow(TM) Ground Glass.

If you would like to contact me, our email address is:
gglass@satinsnowglass.com

I have received a few emails about these types of projects and currently would like to find out, which sized ground glass screens would work best for the applications you folks are using them for, I have been told that 55mm and 52mm are two of the sizes that are being used.

Would you require these in regular screw in filter rings, such as used with 35mm cameras?

Anyway, if you would like, I will try and see what I can put together that may be of assistance to the types of projects you are doing, currently our main focus has been Large Format Film Cameras, but have sold a few screens for use in the DV industry and I am sure I can come up with a solution for those of you that are interested.

Thanks again.

Dave Parker
Ground Glass Specialties
Satin Snow(TM) Ground Glass
www.satinsnowglass.com

David.

There is another method which uses a spinning groundglass to furthur enhance apparent resolution by moving the "grain" of the groundglass through the image faster than the camcorder can resolve it, virtually eliminating it. However, a coarser texture to the groundglass will still affect resolution.

Awhile back, I bought in raw cut optical disks from Ohara in Japan. These were supplied as a special order of 10 with a 15mm diameter center hole and outer diameter of 120mm, a whisker over 5 inches which replicates the dimensions of a plastic compact disk. The thickness was 1.3mm and dressed down to about 0.9mm before the cut marks polished out. The concentricity is an issue for balance but a groundglass texture of uniform quality across the glass means the rpm can be kept down to 1500 or thereabouts which limits vibration.

If you can replicate the compact disk profile with your product at an affordable price, there may be a few making AGUS35s (nicknamed spinners) who might be interested. AO5 dressed spinning groundglass seems to yield about 600 TV lines of resolution at best. Finer than AO5 makes the groundglass too transparent. Thanks for the interest in visiting.

There are some on-site images you can find here at
www.dvinfo.net/media/hart and www.dvinfo.net/media/mellor There may be others here but I don't know of them.

hi : welcome a board david. after trying many types of ground glass the best so far is the optmo sigma 1500 it is 50mm and will fit perfectly in a static tube system . this is the one to beat .
it,.s price is $24 the $ 14 thorlabs is on order and will let you know how that looks maybe your technolgy can better these options. for static devices . but I just got a chance to test out the device that we all hope to equal .the $26,000 ps teknik hd pro model and saw first hand the quality of the ground glass in the $26,000device.
and the optmosigma equaled it .as a matter of fact I think they use a lower grit size than the 1500. for a brighter image
it was amazing the amount of grain that you could see when you powered down the motor . the ocillating disk was about 55mm . I think with future devices the biggest concern is precision of the focal plane. the camera rental place told me that the first generation of the ps tecknik with spinning glass
had a lot of complaints .1 was the vortex of hell. this is caused
by the image not spinning at the same rate the outside of a disc will spin much slower than the inside this was corrected with the $26,000 ocillating adapter . motor vibration was the 2nd complaint . brushless motor and precison parts, and we can make this. maybe there is away to make a piece of glass so good we will not need to ocillate it. that would be a dream

maybe there is away to make a piece of glass so good we will not need to ocillate it. that would be a dream

That's the idea behind the microwax design -- my shipment of wax is pending, but it seems to me to be the only realistic setup that promises a grainless static adapter.

For someone like myself, moving parts, a motor and power supply (not to mention a larger profile) make an oscillating adapter out of the question. For these reasons, if microwax doesn't work, I'll just abide the grain.

- jim

I've just spent the last hour reading this thread.

It's fascinating.

I'm sure you know that this business of a video camera looking at an image formed on a ground glass has been around for years in the form of video-assist cameras taking a peek at the ground glass in a film camera. (In fact, by some very weird coincidence I posted in this very forum yesterday about how clients often mistook the resulting image on the playback monitor as being a telecine of the film rushes!)

Here's an off the wall idea. Suppose you keep the gg stationary, take the lens off, and record an image of the gg illuminated from a light source in front of the camera assembly. You then subtract this image fom the image you get when you have the lens on and focussed on a target. You would have to ensure that the gg stayed absolutely in position.

Also, you might find it interesting to check out the Spintec Lightweight Rain Deflector (http://www.zgc.com/zgc.nsf/active/0278253A70FF953985256A840081377A)

Good luck!

I have found a self adhesive sheet of frosted material from AVERY the same people that make the labels. Probably any sign shop have some scraps. Worth to have a look.

The problem with such materials Valerie is that they have a thickness. Once the light hits one side it will form a sharp image, but will continue to diffuse as it travels through, and become slightly blurred by the time it is viewed from the other side.

A ground glass has a diffusing surface on only side and avoids this.

I personally don't understand how a hot spot is avoided - hotspots are a real bugbear when rear projecting film onto a traditional cinema screen.

hi david...

i have mailed you twice but have recevied a reply that my ail was not sent..(the date can be seen on a few posts earlier)..

i am in the need of 2 pieces of 6cm diameter snow glass for testing purposes..can u tell me the price with included shiping to turkey?

and david...your grains ..what are there sizes scientificly? can u go finer?

thanx..

Vortex from hell ??

I wonder how much of the bad rap Gen 1 of the P+S Technik was due to mismanagement of the system. I found after I had about four of five hours of messing with the early Agus version I could get better results with my primitive setup un-modified. So I imagine the P+S Technik would have required at least that time for the operator's fluency and comfortable familiarity to build up.

Rentals cost money and practice time might be kept to a minimum in some tight budget situations

To Les - I'm really anxious to hear about your osc. device. When is the webpage up and running??? Do you think it would be possible to finish the osc. devices in december???

hi..i have colected the parts..and i have put them together..the system is working fine..i have used a dummy ground glass..since there is still some welding to do..so i cant screw my slr lens on..and for cant do any testing..i have found out that i have used the bearings to tight..(there are looser bearing with the same diemensions..only the turning parts turn easier)..so i have to change them..the friction is much more than i had imagened..but a mechanical engineer friend told me that changing the bearings would solve the problem...i still havent gone in the motor part so i can not test vibration yet..put it works when turning by hand..of course at verrrrryyyy looooowwwww speeds:)

when all done it will be painted with matte black paint..decreasing the reflections inside the device...

here are a few snapshots of where the project is...

www.tumgorsel.com/dosealas/dodo35/dodo_1.jpg
www.tumgorsel.com/dosealas/dodo35/dodo_2.jpg
www.tumgorsel.com/dosealas/dodo35/dodo_3.jpg
www.tumgorsel.com/dosealas/dodo35/dodo_4.jpg
www.tumgorsel.com/dosealas/dodo35/dodo_5.jpg
www.tumgorsel.com/dosealas/dodo35/dodo_6.jpg
www.tumgorsel.com/dosealas/dodo35/dodo_7.jpg

(can some tell me how to put links:)

is anyone going to be offering these kits?

<<<-- Originally posted by Dogus Aslan : (can some tell me how to put links:) -->>>
Great work Dogus!


For the links put the address between these tags
[url] [/urlREMOVE]
Please remove the "REMOVE" text from the second tag. No spaces inside and between the tags!!!

dogus your adapter looks beautiful . I bought bearings for my device and I used a bearing made by boca. a local bearing supplier had a bearing called KBC I think they are made in korea
the kbc were so much better than the boca bearings .
the shaft spins smooth as silk. just flicking you finger on the shaft it spins about 3 seconds. I don't think you need to worry about the ground glass so much I bought a 1500 grit from optmo sigma for the static device . but after seeing the glass used in the $26,000 ps tecknik . they used a glass with way more grain than
the 1500 optmo sigma I have. but I will bet the light loss is less
with their glass . once the glass was spinning it was invisible . so its seems that getting too fine a grain with a ocillating device .
would just lose light stops with no optical gain . the lens adapter was connected to a high def camera. so this would work with mini dv . you also might find.when I used two bearings per plate .
its would spin freeer than one . It seemed to keep the shaft more precisley true. between plates. if it is off even slightly the shaft and bearing will not spin freely

richard can u send a few pictures on your design?

<<<-- Originally posted by Jesse Roberts : is anyone going to be offering these kits? -->>>

i see no reason why not?

-Valeriu

thanx pal... :)

richard can u also give me any information on diemensions and the prices of the bearings?

hi dogus : The bearings that I needed were 8mm od/4mm id
they are made by kbc and the cost was$3.65 each. the company was a local place. I walked in and bought them at the counter
they have a web site but I don't know if they make small orders online. the website is actionbearings.com,

I havent finished with all the parts yet but this is the shaft I am using the bearings fit perfectly. a c clip on the bottom and the top of the shaft is drilled out so I can make a offset and screw it into the shaft . this part is made for a nitro car its strong and precise.

http://www.hobbypeople.net/gallery/554923.asp

when I am finished and all parts work correctly. I promise to give complete parts list and links

I wanted to complete this before I recommend purchases.

but this is something I found that I am buillding my adapter around http://www.surplusshed.com/pages/item/m2213.html the thorlab tube system is just too big to fit this I bought 3 of them the 8mm ball bearings are slightly smaller but the shaft is perfect length. this is a optical grade plate . I think it will be worth drilling 2mm bigger to fit the thorlabs tube system and I belive this will align perfectly .I think surplus shed has about fifty.
each plate will fit two 8mm od bearings per hole . there is room between plate 1 and 2 for pulleys and the third plate when drilled out will hold the tube system which can be adjusted to the 1.2 inch focal length

Richard,

Thanks for the heads up on that part. I saw it on their site a while ago while looking for parts for an Agus 35, and thought it could be a cheaper alternative to a couple Thor Labs parts. Are there any other items you're using in your adapter that may be in short supply? I'm still rounding up parts for that Agus, and now for an oscillating design, and would love to get as many of the parts as I can at one time.

Also, does anyone happen to have a frosted Maxell CD that they'd like to get rid of? I have about 10 clear CDs, but don't want to try and make my own GG. Some of them are quite thick, and look well suited for a homemade GG.

well I gave a link to this before . it can also be used for the tightening , the adjustment rings. in a tube system and filter rings .it will only go about 3/4 of an inch deep though http://www.surplusshed.com/pages/item/m1612d.html

<<<-- Originally posted by Dogus Aslan : hi david...

i have mailed you twice but have recevied a reply that my ail was not sent..(the date can be seen on a few posts earlier)..

i am in the need of 2 pieces of 6cm diameter snow glass for testing purposes..can u tell me the price with included shiping to turkey?

and david...your grains ..what are there sizes scientificly? can u go finer?

thanx.. -->>>

Currently we are only producing square or rectangular pieces of ground glass, but I have started looking into the possibility of producing round glass pieces for this particular application.

So far I have heard there is a need for a piece of fine ground glass about the size of a CD, do you also require the hole drilled into the middle in order to proceed with your project.

I would really like to hear back from a few more indiviuals on this, I am sure I can produce a product that would work for the various applications, but would really like to have some more information.

Thanks again.

If for some reason my main email does not work correctly, I do have an alternative email address of fvww@flatheadvalley.com

I look forward to hearing from some of you.

I do hope I can help.

David Parker
Ground Glass Specialties
Satin Snow(TM) Ground Glass
www.satinsnowglass.com

Dogus-
Amazing pictures! You mentioned painting your adapter. Have you thought about powder coating it instead? Flate finish and if your using aluminum it much less likely to flake on you and get on your GG. What are your parts made out of anyways? If its steel instead of aluminum you might be heading in a world of trouble when you try and oscillate that kind of mass. Shaky video. Dont forget your thinking about using a glass focusing screen instead of a plastic one which will only compound the problem. Have you tested it yet brought it up to speed?

I like you retainer clips for the bearings. Good design. Rock solid/no slack hold on the bearings, right? Custom?

Also how are you attaching the belt and are you going to add grooves into the shafts to keep it on track?

As far as the Satin Snow Glass is concerned....Good stuff, heavy but very little grain. But not too little that it would be good enough to use in a static GG adapter but at the same time its better then any that I have been able to hand make. They are hand ground though (very nicely btw) but I waiting to see if they are consistantly ground enough that I wont get any strobing when put in motion.

Lastly I'm wondering why you have THREE plates with bearings. One off set and two static (in line). Couldnt one offset and one static do the same job. After all it looks like the two plates arent hard mounted together by anything other than the shafts. Doing so might make the system much more stable. Just trying to understand where your coming from. Good stuff.

thanx bret..

the design is plain metal...i had the option to make it from aluminium but the price was x3..so i said i might to stick to metal for testing...aluminium is 5x leighter...in my first design i had parts that needed to be rounded..aluminum is more breakable than metal so i dismissed aluminium then..but now i have found a better way to make the part then to round it..so aluminum is a path still could be taken...i

i havent tested since i havent had time to find a suitable motor and also there is no belt yet...i have thought of making custom belt holder to be put around the mill and the motor..but still time for that...

i will change the bearings today..i have found some which are smoother than the ones i used..but i wonder about the boca bearings (something about the quality i read in there site..nice..)..but it wont be revolving too fast (like 60.000 rpm..this is the limits when u buy a good bearing) and wont have too much weight so...

the metal plates holding the bearings are cut with 0,001 mm (thousandth of a milimeter ) presicieon so i hammer them on slightly..but the metal plates have a 1mm width so there is a slight chance the mills will not be paralel..but putting the second plate on confirms they will all be in position..thats the reason of the second plate...i have gone into design where i also thought of using one plate which is thicker..but there is a approxemetly 45 mm length that needs to be constant between the gg and the slr lens..so i thought i still have plenty of space..ill stick to the 2 plate model...

yeah the mills are custom made..

i dont know what powder couting is? but i had in mind getting it painted to the guys who paint cars..i think its a kind of pray paint? but i dont rely know:)

Thanks. I hope you dont mind me putting in my 2 cents because I really think you have a winning design here and if we can perfect it you might generate enough interest to sell it. Obviously I would love one. At the very least if would serve as a ideal template for what to build others by. On that note I would recomend switching your GG plate for the same thing made out of aluminum. The other plates arent so critical. Also look into using high quality plastic GG or at the very least very thin glass. The bearings on the GG plate would most likely benefit from being extremely small - All for mass/vibration reasons. I hear the P+S Technik motor is a brushless motor so it might be a good idea to focus your searching there. As far as the belt - the P+S Technik has two rubber O-Rings. I guessing that they decided on using two belts because it was physically the weakest link in the system. If one breaks in the middle of a shoot you still have the other one. But keep in mind the more moving parts the noiser it is as well. Another O-ring shouldnt effect it too much at all though.

Keep it up.

-Brett Erskine

brett thanx for the support pal :)hey i didnt start this 2 cent thing..we are all in it! i would love to sell this thing for whom who want...

after your post on the material i ordered cuts of the plates from aluminium..i left some parts metal as i heard that welding of aluminium is 10 times expensive than metal..i suppose i have to see for myself but for now..i share the same idea..the gg layer should be light, the other layers only increase the overall design, not the performance..

brett what is a brushless motor?

i have thought of gear's on the motor and the mill with a suitable belt.. i have made the design so that two belts can be put on the motor to two seperate mills..i think it differs with the mini35 design..they use the belt t o turn all the mills at once..i am planing to rotate only two..the third will be rotated by their tork..

about the noise, i had the idea that when i make this tool..i have to consider two things from the beginning..1- i have to buy an lcd screen and rotate it 180..2 i have to get an external microphone and recorder..

still i hope the noise will be reasanble...

Dogus.

I think you'd better drive all three, otherwise, because of the short stroke and possible compliance in the plates/bearing/bearing mount, crankpin combination, it all might add up to enough lash to intermittantly lock the action causing momentary centers of grain.

David.

The varieties of the appliance fall into three flavours. Regard my following comments as general and without any authority on the subject. Other builders will have better information than mine.

One, the original low cost version used a clear compact disk which had been sandpapered. This disk was rotated to eliminate the coarse texture. This version became known as the AGUS35 after the initiator, Agus Casse.

A 5" CD-R sized disk with 15mm center hole would be required for this type. Except for the cost of the disk itself if made of glass, it is the least expensive of all the options as it is built almost entirely around salvage, but it is also the most bulky. If plastic disks are used, it is very inexpensive.

Construction quality can also be quite imprecise with methods ranging from plastic CD-R packs, silicone adhesive, radiator hose and joiners and gaffer tape assembled on kitchen tables, to precisely manufactured structures built in a workshop but still function effectively provided enough adjustment is permitted in the assembly for the optical center axis to be conformed to. (A version I built has an error tolerance of 5mm or 1/4" and will still work.)

The concept emulates earlier evolutions of the P+S Technik appliances.

Another, a fixed groundglass solution, eliminates any mechanical complications but requires a groundglass of exceptionally fine yet sufficiently opaque texture because the glass does not move.

This appliance by being made often from highly precisely machined optical components such as optical tubes, filter rings and adaptors lends itself from the outset to more satisfactory performance as a precise axis is maintained for the optical path. So far, the texture of the groundglass has been the drawback.

This applicance became known as the ALDU35 after the initiator Alain Dumais.

This concept emulates a fixed groundglass solution, the "Movietube". Groundglass sizes vary in diameter according to the clear metal framed optical filters people buy to grind one side of to create the groundglass. They are entire with no holes in them and much smaller than Agus disks, I think on the ballpark of 52mm filter mount size or maybe 58mm filter mount size.

A third version, which is the topic of this thread is also a moving groundglass design which emulates the later evolution of P+S Technik principles. The motion is orbital. Mechanical movement is very small. The groundglass size required is also small, in the ballpark of the 52mm and 58mm sizes but maybe even smaller.

This version, because it is made of precise components yet under development could yet lend itself to the use of square or rectangular groundglasses in circular frames and maybe the builders will define the glass to a common agreed size. This version also has the highest requirement for competent miniature engineering but uses commercially available components as much as is possible.


SUMMARY:

AGUS35 - Moving disk 5" with 15mm center hole.

ALDU35 - Stationary disk in frame 52mm - 58mm+.

Oscillating designs. - Moving groundglass. Large enough to permit mechanical excursions without edge frame intruding into image projection area.


FOOTNOTE:

Optical glasses tend to be in the ballpark of 1mm - 2mm. I initially thought a CD-R sized (5") glass disk more than 1mm thick would cause two problems.
Vibration due to difficulty in accurately machining and balancing a glass disk.

Gyro effect of large and heavy spinning disk causing the disk to move off the image plane during rapid camera movements.

Subsequently, I found when messing with the wax disks which were much heavier and 2mm thick (two glass disks), there was no unsolvable problem provided the rpm was kept at no more than 1500, the disk was balanced and ran true and the motor given more time to run up to speed.

i am at the stage of finishing the design...i only have motor to select..can any one suggest any type or kind of motor (with reasons)?