Nicholi Brossia:

On the condensor, it's very difficult to tell how 'big' the image is... easy enough on the GG, but the second you put the condensor in front of it, when you look with your eye, you pretty much just see a big bright image all the way to the edges of the lens. If I zoom my camcorder all the way back, I certainly get vignetting - but I'm able to actually see the 'holder' of my condensor, so this is obviously too far back.

If/when I make a second adapter, I would get a larger diameter condensor (43mm is absolute minimum - a 50-ish would be better). I would also use a PCX, which is completely flat on one side, and do my best to get it mounted just shy of contact with the GG.

The bottom pics of the post weren't shot with the 35mm - they were shot with the telephoto, and I actually believe I had zoomed all the way in to 200mm. I don't see the barrel distortion, and I wouldn't expect it with a 200mm lens - You're absolutely right on the 35mm lens - I'd think that would bend like crazy on the edges. I'll have to do some more tests. with straight lines.

I'm nervous as I think about this that I may have bumped my zoom somehow. I had focused on a 36x24 rectangle prior to putting the ground glass and condensor in place, but if my lens is only 43mm - it doesn't seem possible that I could be showing a 36x24mm rectangle (43.6mm diameter). I must have zoomed by accident. Well - more tests - and all the more reason for a larger-diameter condensor.

Yes, I'd like to see the setup on a newer, higher res camera too!! (who knows, maybe for Xmas, I can ask Santa...)

Busy Day
 

Jonathon,
What camera are you using? I'm curious for comparison. The shots look good. I can see the 1000 grit grain though. Your results look very similar to mine. (except your condenser is better than mine and your Alsu35 adapter looks way better!) I hope to get some images of my own work up soon but i keep messing with the design(s). I've got three different adapters in various stages of completion. (Agus35PRO, Aldu35 and vertical mount???)

I spent today completing and testing a vertical mount adapter using an old Minolta SLR body. (like the one used to shoot Marla) I pulled the top cover and gutted it. I had hoped to be able to use the roof pentaprism to get a completely correct oriented image but the clear aperture was just too small for my camera to zoom in on and still be in macro focus range. I had to punt and go for the vertical mount. I am using the minolta's stock condenser which happens to be ground on one side. i had to loose the plastic fresnel element because it had the anoying focus spot in my images . Without the fresnel, i noticed the typical central hotspot though not as pronounced as without any condenser at all . To fix this, I took my 50 mm DCX condenser lens I got from www.surplusshack(no idea on the F.L. but its real thin) and mounted it into an empty 52mm filter ring. I mounted this directly to the video camera. I would love to have a rectangular plano convex (38mm x 26mm F.L. 44mm) to mount directly under the stock Minolta rect. PVX but couldn't find one (anyone know where to get one? I've looked everywhere). I was surprised when I started testing that having the DCX so far from the GG and so close to my camcorder lens still gave me a fairly even image. in fact, with a fast lens (50mm 1:1.4), the hotspotting/vignetting was gone. My image is also correctly oriented vertically but Left and Right are reversed. This is better than dealing with an upside down image but panning is going to take some practice.
That's it for now. I'll put more details and some pics on my website when I get the chance. Joe

Well, erm... umm... (shuffles feet), believe it or not, all I've got at the moment is a JVC GR-AXM220 VHS-C Camcorder. Analog, baby. A soccer mom's dream. And for now, my hobby camera.

Plus - I have to deal with analog capture through a composite signal (ouch). Of course, the whole spirit of this idea is to make do with what we've got. Thankfully, I've got some pretty decent avisynth scripts that I use in post, that help somewhat.

I will certainly upgrade - which was a large motivation for trying to keep my adapter as flexible as possible, so that I could use it with some future camera.

Thanks for the nice words -- yeah, my ground glass needs some serious work. I'm going to order some 3-micron grit, and do a new pass, and see if I can improve that somewhat.

Joe,

Did you have any difficulty mounting the condenser in your empty 52mm ring? (Was that a ring swiped from a UV filter or something?). I thought about going this way, but was worried about getting a good fit between the lens and the ring...

On the rectangular PCX, I've got one that was in my AE-1 - but the focal length (at rough measurement) is about 160mm. I'm not convinced that the focal length has a huge effect as long as its pretty long. You might look for camera parts - I remember doing this and finding a few odd places that supposedly had replacement fresnels and condensors for my old Canon.

Like you, I'm surprised you're having success with a long distance between the condensor and the gg. I had mucho troubles once I got more than a few mm away. If you get close enough to the cam, the condensor actually starts acting like another macro, just giving magnification at very close range... and I don't see how it gathers much lost light from the gg, but you may have found something new that works for you -

Johnathon - helpful hints
 

Johnathon-
Great setup. I agree with the revisions you plan on your design. If you do so we will end up having very similar designs. I'll be able to share mine with you soon. Another thing I would recomend after you get your finer aluminum oxide and PCX lens would be to ditch the GG and grind the flat (plano) surface of the ground glass. Another thing is make sure you get a PCX with a F1 or slightly longer FL. DONT go below F1 otherwise you'll get spherical distortion. If you cant find the FL you want then use two PCX lenses (one on each side of the GG) with two times long focal length for each lens. They will work together to shorten the FL to where you want (ie. fresnel & condenser in a SLR).

Well Im glad the mystery is over. Now all that is left is the prisms. I'll let you guys figure that one out. I want to finally get back to shooting!

P.S. Cylinder Lens = Cheap/Same Quality Homemade Anamorphic Lens Attachment (2.35 and 16X9).

Also anyone shot with the Nu-View 3D system? I didnt know it but its been out for a few years. I know your not going to believe me but I came up with the exact same idea/design a year ago and was hoping to market it then the other day I stumbled acrossed it on the net. Oh well. There goes that business opporunity. Thats alright. I have a few more ideas I've been saving. Anyone have some $$$? ;-)

-Brett Erskine

<<<-- Originally posted by Jonathon Wilson : Joe,

Did you have any difficulty mounting the condenser in your empty 52mm ring? (Was that a ring swiped from a UV filter or something?). I thought about going this way, but was worried about getting a good fit between the lens and the ring... -->>>


No problem at all. I found that the 50mm DCX fit perfectly into the 52mm adapter ring. It was a tiften skylight with a threaded filter holder (not snap ring) I used my homemade filter tool to disassemble for grinding. In fact, the ring was big enough to fit my GG plus a thin PCX.(Aldu35 version) So now I know that a 52mm ring will hold a 50mm lens. i wonder if that holds true for all sizes? (72mm ring/70mm lens etc.) You could assemble your adapter using filter rings. Anyone know a source for empty filter rings? I hate spending $12 for ea.


<<<-- Originally posted by Jonathon Wilson : On the rectangular PCX, I've got one that was in my AE-1 - but the focal length (at rough measurement) is about 160mm. I'm not convinced that the focal length has a huge effect as long as its pretty long. You might look for camera parts - I remember doing this and finding a few odd places that supposedly had replacement fresnels and condensors for my old Canon.-->>>


Does your Canon rectangular PCX have a ground side? I'm looking for one without the grinding as I don't want to have two ground surfaces in the system. (do i?) This was my first time taking an SLR apart and so I only know what is in the Minolta. Do all SLRs use the same configuration? (Lens - Mirror - fresnel w/ focus spot - PCX with GG surface - roof pentaprism - eyepiece lense) Is there a model out there that doesn't have GG on the PVX? Anyone?


<<<-- Originally posted by Jonathon Wilson :
Like you, I'm surprised you're having success with a long distance between the condensor and the gg. I had mucho troubles once I got more than a few mm away. If you get close enough to the cam, the condensor actually starts acting like another macro, just giving magnification at very close range... and I don't see how it gathers much lost light from the gg, but you may have found something new that works for you - -->>>


I think I got away with using the DCX close to the cam lens because most of the image correction was happening through the stock PCX in the minolta. I think the DCX just took the place of the missing fresnel from the original system. I believe you had a problem because your condenser is a lot thicker than mine. I wish I could tell you what the F.L. is on my DCX. How do you measure F.L? I have no idea what the F.L. is on the educational lenses I got from surplusshack.
As I said before, I had a decent image with the fast lens. When I used a 28mm-70mm F3.5-4.6 zoom, I noticed hotspot/vignetting at 28mm but less at 70mm but nowhere near the image quality of the 50mm 1:1.4 . Maybe someone more knowledgable than I can guess why this is so.
Joe

> Does your Canon rectangular PCX have a ground side?

No, it's completely clear.

> Do all SLRs use the same configuration?

My Canon AE-1 was identical to your description, except that the PCX is not ground. My fresnel/focusing ring has the ground surface on one side.

Hello

i got the nu-view system.
It is a well made gadget you can screw on a camcorder lens (as long as you got the the way to do it, that is not obvious on many cheap model)
the diameter is 37mm so it fit best cam with this size.
you connect the cinch cable in the composite video out of the cam to genlock the LCD shutter of the gadget to your cam.
I am working with PAL 50fps so the result is a bit like looking on a 18 fps old movie.
That is less noticeable when you use NTSC with 60fps.
I got the wireless LCD glasses that you can order with the nu-view.
From a pure technical point of view, i can say it works very well.
Amazing 3D as advertised.
From another point of view, the fact that playing the tape requires the LCD glasses limit the use of it to a friend/family circle.
Frankly, the product is great, but it is now somewhere in a drawer since almost 2 years because i found no really use than just making some shot for fun and i think they are not producing it anymore. so, good idea, but I doubt you could become rich with it.

Brett Erskine
 

Brett, I have two questions for you (and anyone else who wants to chime in):

1. Did I understand you correctly as saying that it would be a good idea to grind the plano side of the condensor instead of having a separate GG? I was thinking that earlier, wondering if it is so important to get the condensor so close to the GG, why not just grind the flat side... then I see you saying something similar. Am I hearing you right?

2. Okay, I'll take the bait on the cylinder lens. You have mentioned it in a couple of threads now, and you've got me interested. Can you give more info on this? Is this something that could be incorporated into the Aldu35 setup?

a couple of links for optics
 

http://www.anchoroptical.com
http://www.sciplus.com/category.cfm?subsection=21

Images from Vertical Mount adapter
 

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.

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

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.

Porro prisms
 

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

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?

aldu 35
 

hi everyone I e mailed chris screen grabs of my aldu35

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.

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.

aldu 35
 

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

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.

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.

FAQ mini 35
 

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

http://mini35.lickthetoad.org/

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!

to frank ladner
 

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

new idea for testing!
 

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

Filip: Thanks for that link! Stuff like that helps me out a lot.

If we could get a ground glass with grain fine enough to be acceptable for the high megapixel still cameras, it should be more than good enough for a DV camera.

if you want to test the size of the grain on your gg, just point a laser in one end of your adapter and shine the output against a white surface. This magnifies the grain so you can see it.

Frank,

This second round of grabs looks great!!! So much better than the first. You must be getting excited about your adapter. I have just a few quick questions to help me appreciate what you've posted even more.
What size and F# SLR lens are you using?

How much of the original SLR image on the GG are you shooting? Are you zoomed in at 36mmx24mm or are you wider? (I get rid of my hotspot & vignetting when I zoom in onto the GG image but I'm afraid I'm tighter than 36mm & 24mm and so am losing some benefit of 50mm SLR lens vs. shooting with vid cam's original long lens)

How bright was the day you were shooting in? Time of day?

The images had a definate blue hue to them. Do you think that was the polarized GG?

I also noticed some slight barell distortion with the image of the post and the planks. Do you think your condenser is too strong? I had the same distortion when using a wide angle SLR zoom lens(35mm at F3.5) with a thick condenser. The distortion went away with a 50mm 1:1.4 lens with the same condenser. I haven't had any luck with a WA lens yet. 45mm is the shortest I've been able to use without distortion or hotspotting and vignetting.

Thanks for sharing, Joe

John: Thanks for the tip! I'll have to find a laser now. :-) I notice when holding the camera at certain angles and a flare hits it, the grain is really easy to see.

Joe: Thanks!

The lens I'm using is a Pentax 1:2 50mm.

Having a lens on each side of the groung glass, I get an evenly bright image. (I can actually stop down the aperture on the 35mm lens and not get a hotspot. However, the grain starts to jump out at that point.) Honestly, I have been just zooming in until I don't see the outer ring of the adapter. Not too precise. I may be tighter than 36x24mm.

The time of day was around 1:00. Brighter than when I shot the other images.

About the blue hue: It could have been the polarizer, or I may not have had the white balance doing the right thing. Next time I will white balance off something.

The distortion is really noticeable when panning around. My condenser may be too thick. I'm trying to get some more lenses to play around with. Maybe I can verify if it is condenser thickness.

Thanks for checking the images out!

,Frank

Frank-
First of all nice work. To narrow down if your getting distortion from your 35mm lens or your condenser do this simple test:

Focus on something at infinity with a film lens 50mm or longer. Find something that has straight lines and put that line near the outer area of your frame. If that line looks curved then its your condenser lens that causing the problem.

What you'll need to do is find a different condenser that has the closest to a F1 rating or higher. Now when I say F1 I DO NOT mean f stops. Instead a condenser that has a F1 rating is one that has a focal length equal to its diameter. If you have a lens that has a focal length shorter than its diameter then you will begin to have spherical distortion like you discribed. On the other hand if you have a lens that has a longer focal length then its diameter you will not but as that focal length gets longer its ability to culminate light diminishes. From my experience it generally is best to go with a condenser with a focal length the same or slightly longer than its diameter.

Also make sure to get a condenser a least 5mm larger in diameter then what a 36mm X 24mm image will allow due to the optical quality of lenses at their very edges.

-Brett Erskine

Condenser
 

Brett thanks for your explination about condenser lens.

Why you hare talking about frame 24mmX36mm

i test whit 27mmX36mm 4:3 ratio and is working just fine

and watt abour chromatic aberations ????
some one find doublets (crow-flint) lens ????

just to check - you are talking of condenser in this position:

|)(|

yes?

filip

Condenser Lens clarification
 

Brett,

Thanks for clarifying the F1 condenser rating. I now better understand a message you posted a while back. So to clarify...
(1) 50mm dia. PCX with a FL=50mm is F1?
(2) 50mm dia. PCX with a FL=100 mm ea. is also F1?

Based on how my Minolta has the rectangular condenser set up in the focus plane, I'd guess the configuration for adapter as follows. Please correct me if this is wrong.

Single PCX....... SLR] l) [Vid Cam (flat surface of PCX is GG) ???

double PCX ....... SLR] (ll) [Vid Cam (flat surface of 2nd PCX is GG) ???

The above is a question not a statement of fact. Thanks for the help, Joe

1)Yes
2)No. Greater than F1

Yes
Yes

I got a little confused from the last couple posts. Brett, your explanation of F1 makes total sense. A 50mm focal length would be ideal for a 50mm diameter PCX lens. In an earlier post, you stated So essentially, considering the lenses are all the same diameter, two 100mm focal length lenses in series are equal to one 50mm focal length lens. That is what Joe seemed to be asking earlier, but you stated that it wasn't correct. It looks like the (1) and (2) may have caused a little confusion, so I'd just like to double check.

One 50mm focal length PCX lens with 50mm diameter = F1.
Two 100mm focal length PCX lenses with 50mm diameters > F1?
Two 50mm focal length PCX lenses with 50mm diameters = ?

Brett: Thanks on the images, and thanks for that detailed explanation! That makes sense about having a larger condenser due to image quality at the edges. I will experiment further and try that test. I will try to post something when/if I make any progress.

One 50mm focal length PCX lens with 50mm diameter = F1.
*Yes

Two 100mm focal length PCX lenses with 50mm diameters > F1?
*Yes, in the sense that the two lenses would work together to shorten the focal length to 50mm. As to whether you could give the TITLE of F1 to two lenses working in series Im not sure (probably not) but who care. I only mention it in case you guys are shopping for two lenses and hoping it will state their combined F number.

Two 50mm focal length PCX lenses with 50mm diameters = ?
*25mm. A interesting thing about this example is I believe (but Im not sure) that by combining two lenses with F1 ratings you get the best of both worlds. A shorter focal length and no spherical distortion.

Does that help?

-Brett Erskine

Yeah, that helps a lot. If you have any more pointers, I'd love to hear them. Thanks for the help Brett.

PCX lens questions
 

Where are you guys finding the best PCX lens?

Has anyone found PCX lens already mounted?

Hate to be the newbie, but what does PCX stand for, and in lamens terms, what make PCX such a good choice?