35mm Adapter Static Aldu35

Ari Shomair · February 28th, 2004, 10:37 AM

He just typed the URL wrong, the right one is:
http://www.ideaspora.net/aldu35/
Part 3 of the tutorial doesn't seem to exist though

Jim Lafferty · February 28th, 2004, 11:02 AM

Sorry bout that -- was in a rush. The link's fixed, and part 3 will be up in a few days.

- jim

Ari Shomair · February 28th, 2004, 11:05 AM

Nice, I'm excited to see it ;)

John Gaspain · February 28th, 2004, 12:32 PM

Jim, you need a condensor.

Alain Dumais · February 28th, 2004, 01:36 PM

In your tutorial about the grinding, normaly you should do the reverse, the square glase on the table and the filter on top, so you'r moving the filter ,use two square of glass and altern betwen both at 5 to 10 min interval. That way you are having lens chance of imperfection or uneven GG.

About the inversion I don't know if it's make a big difference , but that's the way I have learn it, maybe it's not important.I just tell you.

But is this becoming a very good tutorial.

Alain

Frank Ladner · February 28th, 2004, 01:46 PM

Jim: I may have to break down and gut a quality lens form Century Optics. Not sure yet, but thanks for the info!
,Frank

Giroud Francois · February 28th, 2004, 04:45 PM

for those who need to rotate the GG, i thing there is something good to get from a very thin roller bearing like the ones you can find here
KAYDON http://www.reali-slim.com/pdfs/kayd...log.pdf#page=15)

Brett Erskine · February 29th, 2004, 12:37 AM

Instead of PVC for our adapter's adjustable housing - why not try a still photography lens without its internal optics. There are so many cheap 35mm/medium format lenses out there (even cheaper to buy if they are already broken). Often times the older still lenses have a smoother feel to their focusing ring and if you get a lens with internal focus you wont have to deal with your whole adapter spining around as you adjust and set focus.

The only problem is its going to be hard to find a lens with both a extrance and exit aperature large enough for our 36mm X 24mm gate.

And if anyone knows of where to get lens housing minus their optics let us know.

-Brett Erskine

Tavis Shaver · February 29th, 2004, 12:58 AM

thats a greaat idea Brett. Would it be possible to cut the smaller end of the lens to accomodate the gate?

Brett Erskine · February 29th, 2004, 01:02 AM

Im not sure. Each lens has its own internal lens design and changing it like that might create serious problems.

Another option is a ready made adjustable extension tube.

-B

Brett Erskine · February 29th, 2004, 01:08 AM

Early on I thought I about using bellows but figured they couldnt handle the weight of some of the large zooms (particularly PL mount cine zooms). And perhaps Im being picky but it would give the adapter a old fashion look that I wasnt going for.

-B

Giroud Francois · February 29th, 2004, 01:16 AM

I dismantled several zoom lens for that purpose and answer is yes, it is possible but there is an heavy way of cutting the 24x36 window into the moving part, as this one usually is smaller..
the mechanic is infact just 3 bars acting as guides, with two plates (front and rear) moved by a small cursor driven by the slot of the main cylinder.
that is for tele zoom system, range is very big.
for a smaller fixed lens, the mechanic is simpler and range should be better (smaller)
A variable system is good in fact for a prototype, but for the final one, if you got all the correct distance, there would be no need to have this.
you can screw together 2 filters mount , one with the lens or glass and one empty, and you got 2 or 3 turns on the screw to have a bit of adjusting available.

Brett Erskine · February 29th, 2004, 01:37 AM

Actually if you plan on using more than one type of lens (Nikon, Canon, PL mount) they all require different focal lengths. The difference between one lens maker and another might be the difference of one or two threads while others are much more dramatic. Check the flange focal length chart to see what you need.

Bottom line you DO need a adjustable adapter if your going to use both Cine and Still lenses.

-Brett Erskine

Giroud Francois · February 29th, 2004, 08:45 AM

i think for those who go the full fledge device, they should choose for a short distance from the gg to a T-mount and then use t-mount converter to their lens mount (10$ at http://surplusshed.com/) so they can modify the adapter to get the proper distance.
edmund optics has such t-mount ring you can assemble to have the distance needed http://www.edmundoptics.com/IOD/DisplayProduct.cfm?productid=1382
and t mount tubes
http://www.edmundoptics.com/IOD/DisplayProduct.cfm?productid=1285
My opinion is that moving the lens (that is a removable stuff anyway) is more convenient than having a movable gg
K.I.S

actually if you plan a simple kit assembly minidv35 by just screwing together already made element, the T-mount 42mm format is very good. you will find lens or lens adapter, tubes, filter (for the glass) and many lens are around this size.
Edmund optics as a very complete offenring into T-mount parts, but it will push the budget envellope a bit higher and it worth it since you couldget your minidv35 ready in only few hours.

anyway at http://surplusshed.com/ you will really find for cheap everything you can dream for your homemade minidv35.
From the single lens to a full tele zoom for parts.
and some cheap t-mount lense here
http://www.colescameras.com/tmount.htm
in a surplus shop i got on saturday a old but never used TTL camera
(brand PETRI) with a 50mm and 135 lens for 40$.
it is almost a shame to break it, it looks so good, but it has a nice T-mount ring fixed on the body with 3 screws that would be perfect on my prototype.
I will try to find another t-mount support, if i can

Giroud Francois · February 29th, 2004, 10:31 AM

I just get a question about lenses.
for the same type of lens (50mm for example) you got different "f" value.
I suppose this reflects the aperture of the lens.
What i do not know is if there is a difference between a high end lens that give lot of light and a cheap one that probably has few "f" more. Probably it matters when using films but what about using a CCD.
Is there an equivalence between a CCD(lux sensitivity ) and ASA ?

February 28th, 2004, 10:37 AM	#391
Ari Shomair Major Player Join Date: Dec 2003 Location: LA, California, USA Posts: 224	wrong URL He just typed the URL wrong, the right one is: http://www.ideaspora.net/aldu35/ Part 3 of the tutorial doesn't seem to exist though

February 28th, 2004, 11:02 AM	#392
Jim Lafferty Major Player Join Date: Dec 2003 Location: Brooklyn, NY Posts: 636	Sorry bout that -- was in a rush. The link's fixed, and part 3 will be up in a few days. - jim __________________ Realism, anyway, is never exactly the same as reality, and in the cinema it is of necessity faked. -- J-L G

February 28th, 2004, 12:32 PM	#394
John Gaspain Major Player Join Date: Oct 2003 Location: WA-USA Posts: 371	Jim, you need a condensor. __________________ The glory of the World passes by.

February 28th, 2004, 01:36 PM	#395
Alain Dumais Regular Crew Join Date: Jan 2004 Location: Montreal Canada Posts: 86	Hi Jim In your tutorial about the grinding, normaly you should do the reverse, the square glase on the table and the filter on top, so you'r moving the filter ,use two square of glass and altern betwen both at 5 to 10 min interval. That way you are having lens chance of imperfection or uneven GG. About the inversion I don't know if it's make a big difference , but that's the way I have learn it, maybe it's not important.I just tell you. But is this becoming a very good tutorial. Alain __________________ http://www.kheops-tech.com/~ad3d/

February 29th, 2004, 12:37 AM	#398
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	Use Empty Lens Housings as High Quality Focusing Tubes Instead of PVC for our adapter's adjustable housing - why not try a still photography lens without its internal optics. There are so many cheap 35mm/medium format lenses out there (even cheaper to buy if they are already broken). Often times the older still lenses have a smoother feel to their focusing ring and if you get a lens with internal focus you wont have to deal with your whole adapter spining around as you adjust and set focus. The only problem is its going to be hard to find a lens with both a extrance and exit aperature large enough for our 36mm X 24mm gate. And if anyone knows of where to get lens housing minus their optics let us know. -Brett Erskine

February 28th, 2004, 11:05 AM	#393
Ari Shomair Major Player Join Date: Dec 2003 Location: LA, California, USA Posts: 224	Nice, I'm excited to see it ;)

February 28th, 2004, 01:46 PM	#396
Frank Ladner Major Player Join Date: Aug 2003 Location: Poplarville, MS Posts: 453	Jim: I may have to break down and gut a quality lens form Century Optics. Not sure yet, but thanks for the info! ,Frank

February 28th, 2004, 04:45 PM	#397
Giroud Francois Inner Circle Join Date: Feb 2004 Location: switzerland Posts: 2,133	for those who need to rotate the GG, i thing there is something good to get from a very thin roller bearing like the ones you can find here KAYDON http://www.reali-slim.com/pdfs/kayd...log.pdf#page=15)

February 29th, 2004, 12:58 AM	#399
Tavis Shaver Major Player Join Date: Oct 2003 Location: Vancouver, BC. Canada Posts: 209	thats a greaat idea Brett. Would it be possible to cut the smaller end of the lens to accomodate the gate?

February 29th, 2004, 01:02 AM	#400
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	Im not sure. Each lens has its own internal lens design and changing it like that might create serious problems. Another option is a ready made adjustable extension tube. -B

February 29th, 2004, 01:08 AM	#401
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	Early on I thought I about using bellows but figured they couldnt handle the weight of some of the large zooms (particularly PL mount cine zooms). And perhaps Im being picky but it would give the adapter a old fashion look that I wasnt going for. -B

February 29th, 2004, 01:16 AM	#402
Giroud Francois Inner Circle Join Date: Feb 2004 Location: switzerland Posts: 2,133	I dismantled several zoom lens for that purpose and answer is yes, it is possible but there is an heavy way of cutting the 24x36 window into the moving part, as this one usually is smaller.. the mechanic is infact just 3 bars acting as guides, with two plates (front and rear) moved by a small cursor driven by the slot of the main cylinder. that is for tele zoom system, range is very big. for a smaller fixed lens, the mechanic is simpler and range should be better (smaller) A variable system is good in fact for a prototype, but for the final one, if you got all the correct distance, there would be no need to have this. you can screw together 2 filters mount , one with the lens or glass and one empty, and you got 2 or 3 turns on the screw to have a bit of adjusting available.

February 29th, 2004, 01:37 AM	#403
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	Actually if you plan on using more than one type of lens (Nikon, Canon, PL mount) they all require different focal lengths. The difference between one lens maker and another might be the difference of one or two threads while others are much more dramatic. Check the flange focal length chart to see what you need. Bottom line you DO need a adjustable adapter if your going to use both Cine and Still lenses. -Brett Erskine

February 29th, 2004, 08:45 AM	#404
Giroud Francois Inner Circle Join Date: Feb 2004 Location: switzerland Posts: 2,133	i think for those who go the full fledge device, they should choose for a short distance from the gg to a T-mount and then use t-mount converter to their lens mount (10$ at http://surplusshed.com/) so they can modify the adapter to get the proper distance. edmund optics has such t-mount ring you can assemble to have the distance needed http://www.edmundoptics.com/IOD/DisplayProduct.cfm?productid=1382 and t mount tubes http://www.edmundoptics.com/IOD/DisplayProduct.cfm?productid=1285 My opinion is that moving the lens (that is a removable stuff anyway) is more convenient than having a movable gg K.I.S actually if you plan a simple kit assembly minidv35 by just screwing together already made element, the T-mount 42mm format is very good. you will find lens or lens adapter, tubes, filter (for the glass) and many lens are around this size. Edmund optics as a very complete offenring into T-mount parts, but it will push the budget envellope a bit higher and it worth it since you couldget your minidv35 ready in only few hours. anyway at http://surplusshed.com/ you will really find for cheap everything you can dream for your homemade minidv35. From the single lens to a full tele zoom for parts. and some cheap t-mount lense here http://www.colescameras.com/tmount.htm in a surplus shop i got on saturday a old but never used TTL camera (brand PETRI) with a 50mm and 135 lens for 40$. it is almost a shame to break it, it looks so good, but it has a nice T-mount ring fixed on the body with 3 screws that would be perfect on my prototype. I will try to find another t-mount support, if i can

February 29th, 2004, 10:31 AM	#405
Giroud Francois Inner Circle Join Date: Feb 2004 Location: switzerland Posts: 2,133	I just get a question about lenses. for the same type of lens (50mm for example) you got different "f" value. I suppose this reflects the aperture of the lens. What i do not know is if there is a difference between a high end lens that give lot of light and a cheap one that probably has few "f" more. Probably it matters when using films but what about using a CCD. Is there an equivalence between a CCD(lux sensitivity ) and ASA ?