Mini35 Oscillating Ground Glass Idea

Richard Mellor · October 26th, 2004, 09:48 AM

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

Dogus Aslan · October 26th, 2004, 10:40 AM

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

Brett Erskine · October 26th, 2004, 04:13 PM

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

Jim Lafferty · October 26th, 2004, 04:24 PM

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

Dogus Aslan · October 26th, 2004, 08:00 PM

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..

Brett Erskine · October 26th, 2004, 09:20 PM

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.

Dogus Aslan · October 26th, 2004, 09:43 PM

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..

Brett Erskine · October 26th, 2004, 10:18 PM

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.

Richard Mellor · October 27th, 2004, 09:08 AM

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

Dogus Aslan · October 27th, 2004, 12:29 PM

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..

Brett Erskine · October 27th, 2004, 03:04 PM

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.

Dogus Aslan · October 27th, 2004, 04:00 PM

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:)

Brett Erskine · October 27th, 2004, 11:05 PM

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

Jonny Dee · October 28th, 2004, 06:11 AM

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!

Jim Lafferty · October 28th, 2004, 09:49 AM

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

October 26th, 2004, 04:24 PM	#259
Jim Lafferty Major Player Join Date: Dec 2003 Location: Brooklyn, NY Posts: 636	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 __________________ Realism, anyway, is never exactly the same as reality, and in the cinema it is of necessity faked. -- J-L G

October 28th, 2004, 06:11 AM	#269
Jonny Dee New Boot Join Date: Oct 2004 Location: Toronto Posts: 16	Thorlabs parts 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!

October 26th, 2004, 09:48 AM	#256
Richard Mellor Major Player Join Date: Nov 2003 Location: cambridge ma Posts: 247	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

October 26th, 2004, 10:40 AM	#257
Dogus Aslan Regular Crew Join Date: Apr 2004 Posts: 56	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

October 26th, 2004, 04:13 PM	#258
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	Dogus- Did you have all thoughs parts professionally custom made? What was the total cost?

October 26th, 2004, 08:00 PM	#260
Dogus Aslan Regular Crew Join Date: Apr 2004 Posts: 56	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..

October 26th, 2004, 09:20 PM	#261
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	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.

October 26th, 2004, 09:43 PM	#262
Dogus Aslan Regular Crew Join Date: Apr 2004 Posts: 56	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..

October 26th, 2004, 10:18 PM	#263
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	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.

October 27th, 2004, 09:08 AM	#264
Richard Mellor Major Player Join Date: Nov 2003 Location: cambridge ma Posts: 247	brett : regarding the shaft you are looking for, how long does it need to be . and what would the diameter be

October 27th, 2004, 12:29 PM	#265
Dogus Aslan Regular Crew Join Date: Apr 2004 Posts: 56	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..

October 27th, 2004, 03:04 PM	#266
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	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.

October 27th, 2004, 04:00 PM	#267
Dogus Aslan Regular Crew Join Date: Apr 2004 Posts: 56	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:)

October 27th, 2004, 11:05 PM	#268
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	I called. Heres their site: http://www.satinsnowglass.com/index.html

October 28th, 2004, 09:49 AM	#270
Jim Lafferty Major Player Join Date: Dec 2003 Location: Brooklyn, NY Posts: 636	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