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

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

- jim

Nice, I'm excited to see it ;)

Jim, you need a condensor.

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

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

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)

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

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

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

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

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.

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

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

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 ?