35mm Adapter Static Aldu35

[Joe Holt]

Hello all,

I've just put up some frame grabs of the footage I shot Saturday with my vertical mount adapter. I also have some shots I took this evening of the adapter. Let me know what you think, Joe

http://www.paddlefilms.com/vm35mmadapt.htm

James Webb,
Thanks for the links. I'm especially intrigued with the Anchor Optics link. I've been looking for a source of Porro Prisms for experimenting with. Anybody know of any other sources for abbe porro prisms and/or large roof penta prisms? I'm really hankering for a correctly oriented image.

[Brett Erskine]

Justin-
Yes. Grind the Plano side of your PCX lens.

A cylinder lens is a lens that has the effect of squeezing the image on either the horizontal or vertical axis. Next time your on a shoot with anamorphics such as Panavision look down the lens. That first element you see in front is the cylinder lens. You can also find them in the much talked about anamorphic adapter for cameras like the DVX100 but thoughs are only sold for 16X9 shooting not 2.35. Not to mention your paying big money for a simple lens. Check out some of the optical suppliers listed on this forum and hunt down one big enough for your camera. If your going for 2.35 you'll want a lens with specs that bend horizontal light by a factor of 2X. And if you want 16X9 = 1.78X. And 1.85 = you guessed it. And to answer your question about if it can be used with our adapters. Yes. Absolutely. They can be used in front and behind the adapters we are making. Having a intermediate image opens yourself up to this and so many other things as well. Thats why this is one of the most read and written threads on DV.

-Brett Erskine

[Bob Hart]

A handy piece of work. Have you tried clicking the Minolta shutter yet.(Built-in press photo effect)

Porro prisms can be had in sizes which would work. They have to positioned in 90 degree opposition which rotates the image 180 degrees. I haven't made an erector with prisms yet but have tested the principle with mirrors masked down to 40mm on a PD150. Mirrors unless they are surface coated are no good due to multiple internal reflections.

I intend to enquire with the vendor to see if two prisms could be bonded together with UV glue used for lens elements which would eliminate one or two problems.

[Joe Holt]

Bob,

I'm glad to hear someone else is still striving for a corrected image. please post whatever you find out about the porro prisms. Could you make the same effect using surface coated mirrors? Anchor optics (link provided by James Webb earlier) has what appears to be a large variety of sizes in surface coated mirrors. My guess would be that the prisms would still be superior but oh so expensive. Anchor also lists some porro prisms but I have no idea what size would be needed.


Brett,

Very interesting stuff about the cylinder lens. I've never used (or even seen) an anamorphic adapter. I understand the principle of how they work but have only read about them. Could you or anyone give a brief description of how they're put together? So the front element is a cylinder lens, what else is needed to make your own anamorphic adapter? Anyone? This could become its own thread.

Thanks, Joe

[Simon Wyndham]

With so many ideas arounf my head is spinning! I would like to construct something soon, but keep delaying in case someone comes up with a better solution!

I am wondering whether now would be a good time to;

a) have a thread recap on the general consensus on how to make a decent workable version of a static adaptor, and

b) whether it might be a good idea to have a sticky thread where people can post links to pictures or finished adaptors, and if anyone is so inclined to make one, links to instructions etc on how to build such an adaptor. This way people could quickly look at working examples rather than wading through this monster (yet highly interesting) thread.

What do y'all think?

[Richard Mellor]

hi everyone I e mailed chris screen grabs of my aldu35

[Brett Erskine]

I dont want to get too into the cylinder lens because its not part of most of the Aldu35 designs out there and should be part of a new thread, however I will say when you shop make sure its achromatic (two elements) for the usual reasons. Another thing too. My numbers are wrong for the mag. power for both 16X9 and 1.85. I'll have to do the math and post them. I can tell you that the number for 2.35 (actually 2.39) is correct. Anyways go luck on your designs guys.

[Giroud Francois]

For the recap:

The static adapter requires to solve 6 problems:

1) the mount of your 35mm lens to the "tube".
Many solutions found until now, the easiest is to use the plastic cap from the lense.
If you are taking the lense from an old dead body, keep the the ring (usually fixed with 4 screws) to fix the lens.
You can probably find old body from ebay or your photo reseller for very cheap. Keep in mind that the space between the GG and the lens is about 45mm depending the brand of your lens.
(Pentax-K lens 45mm,Nikon 46.5 and the Canon only 44mm)
I got some contact with an Australian guy who should be able to build reverse adapter for Pentax K, Canon FD and Nikon to M42.
I think that is the best way so you are not limited to one brand.
If several people are interested we would probably get better prices.

2) the GG.
Now we got many supplier link for white (the best) or blue (not recommended) Aluminium oxide with grit=1000 (or over). Some other tracks about cerium oxide (finer than A.O.)
Making is own GG is still a long task and the process is not 100%, so be prepared to have the job done several times.
Using a UV filter glass or using directly the flat side of the condenser lens is still under comparison.
Additionally, i think that mounting the GG inside a big roller bearing could be an opportunity to have the GG moving a way or another and do not add too much complexity to the build.
Remember: the picture size is at least 24x36mm, so the minimum diameter for a round glass and tube should be 44mm.

4) getting rid of vignetting
That is the role of the condenser, and we know that only one lense is ok, but better result could be obtained with several lenses disposed around the GG. This has been to be checked.
Obviously the bigger your lens (at least 50mm diameter) the best your result is.
seems the FL of the lens is not too critical and should be big.
(means the curved side of the lens should look very flat).

5) the macro lens.
This is very dependent from the optics of your camera, so no general rules, except you can expect that a +7 lens will be needed.
An achromatic lens is mandatory, since a macro len is very sensitive to color distorsion in the border of the lens.
Again, the bigger the diameter of the lens, the better.

6) putting all the stuff into a nice box or tube with right distances.
Seems the best builds are made with aluminium tube from old zoom lenses, keeping the "photo" look.
Plastic is ok too, but some problems to have it black inside, if not already of that color.
Advantage of plastic is you can easily cut and glue the part together. recommended for prototype.

[Richard Mellor]

the shots were made on a 1 ccd panasonic pv-401 with a aldu 35 . and a cannon 50mm 1.8 lens. color curves in vegas output to windows media 9 1280x720 frame grab power dvd


http://www.dvinfo.net/media/aldu35

[Frank Ladner]

Here are a couple of links you guys may be interested in.

"Flat Black Paint for Lenses and Telescopes"
http://medfmt.8k.com/mf/black.html

Do It Yourself 35mm page:
http://keinaths-fotohomepage.gmxhome.de/35/35-links.htm
(Not video stuff, but some of this may be helpful.)

Richard: Nice images! You guys keep up the good work.

[Bob Hart]

Joe.

I have actually tested a mirror based erector in the path between the GG and PD150 wiith a simple 58mm diam close-up lens of 4+ and a stack of 7+. ecause of the longer path created by the mirrors you don't need the same power in the close-up lenses for the same distance from gg to camcorder. Ordinary wardrobe mirrors cut up are quite useless as there is this incredible pattern of parallel lines around pinpoint bright spots in the image. Surface coated mirrors would work.

There is a bit of image stuff on my early prototype erectors at www.dvinfo.net/media/hart

There's been furthur evolutions which have been smaller, but I haven't followed up yet as I have other things to do presently

For mirrors, I would be inclined to make my mount out of lightwieght sheet metal (tin cans or thin brass which can be soldered).

For a porro prism mounting block, I would prefer to use fine particle board or craftwood which would protect the prisms from mechanical damage.

[Paolo Rudelli]

new FAQ of mini35 in FRENCH wellcome to all "french" speaker

http://mini35.lickthetoad.org/

[Frank Ladner]

I have uploaded another page of framegrabs to my site.

http://www.frankladner.com/testpics2.htm

These look better than the first frames I uploaded. There is less grain, and the vignetting is greatly reduced.

Thanks!

[Filip Kovcin]

frank,

thank you for the links,

i found that link very interesting, so if you don't mind - i feel free to put it here in a bit modyfied mode - directly to lens calculators -it may help someone.

http://www.astronomyboy.com/eyepieces/ep_calc.html


filip

[Filip Kovcin]

i have a new (maybe?) idea about the aldu35.

does anyone have possibility to check aldu with
DIGITALL STILL CAMERA? with, say 5mega pixel?

i'm curious what we will see. how much of the grain is visible in that resolution.
i know that we are working with different cameras with different CCDs, but when we are talking about griding the GG - how far we must go to make it almost unvisible? i understand - if the grain is ok for the better (more megapixels)CCD - like in digital still cameras - it will fit our needs for DV. correct?

just a thought.

filip