Homemade 35mm -- Edited Copy for Reading

[Bob Hart]

An interesting product available at the following web address,

www.scopetronix.com/maxview2.htm

conveys the image from a telescope to digital cameras with 58mm filter thread. May possibly work with the PD150/VX2000 camcorder family but may frame only the up to 18mm diameter image target my own adaptor does due to the smaller CCD area of motion video cameras compared to still cameras.

[Louis Grimaldo]

I thought there have been several people who have tried Spencer's method with no luck. Hey Spencer, could you post some more footage once you have the whole thing completed? Maybe having the +10 macro is the ticket. It's hard to believe that it's that simple.

[John Gaspain]

<<<-- Originally posted by Spencer Houck : Ok, so as I said above I finally got my grubby little hands on a +10 macro adapter for my VX2000. I was fooling around with my new ability to gather close focus to the frosted cd when all of the sudden, to my delight, I realized that when I wasn't holding the cd in place a clear image was seen from just zooming right into the center of my 50mm lens. It's a 50mm 1:1.8 Olympus lens. So here's a design featuring literally no GG at all, just zoomed through the +10 macro's vignettes, and the 50mm lens' vignettes, and voila no grain, no fuss.

So, to exaggerate my point, I have a 50mm SLR lens placed about 4.5 inches in front of my VX2000 with a UV adapter and a +10 Macro adapter on it. THATS IT!

It's shaky due to the fact that nothing is mounted, its just sitting on my table...not light tight whatsoever. Notice the HUGE amount of breathing when focusing (the changing of size of objects when focus is shifted) Don't know what to do about that, pretty much a feature of inexpensive still camera lenses, but in general I'm really happy with this...

So please watch the short clip I've captured, it's under tests on this page:

http://www.par-t-com.net/media.html
(The image was flipped in post)

...and then bring me back to Earth as to why this won't work for some probably obvious reason.

Happily,
Spencer Houck -->>>

NICE WORK!..I tried and failed. I have the same Oly lens too, Maybe if I try a macro lens with it.

[Spencer Houck]

<<<-- Originally posted by Peter Sciretta : What +10 macro adapter do you have? Brand? Model? -->>>

It's a "samigon" branded (1:1) Macro Close-Up Lens +10 58mm made in JAPAN. So says the little oldschool box it came in. I got it from a store called Campus Camera, at the local university. It caters to still photography, so I'm assuming most well stocked still photography stores would have something similar.

<<<-- Originally posted by Rob Hester :J ust wondering though, isn't the image also zoomed? -->>>

As far as I can tell the image is just as if you were using a ground glass. In essence I'm still taking a picture of a picture. The zooming by 7x happens with XL1's with 35 mm lenses adapted directly to them, projecting the 35mm negative's image right onto the camera's CCD. The 50mm lens I'm using must pass through my VX2000's lens, so the CCDs are not being projected onto directly, so it doesn't magnify.

Also with that direct coupling on the XL1 you don't recieve the DoF of the 35, so by default I don't think thats happening, cause i'm experiencing some "XtremE Shallow DoF".

One thing to note tho, is that for mine to work, the 50mm lens itself must be shifted 1 and 7/8s of and inch to and fro the VX2000 to achieve focus of 4 inches to infinity.

-Distance of 3 5/8 inches from the back of my 50mm lens to the front of my camera's housing(not the front of the +10) gives me a focus of infinity.
-Distance of 5 1/2 inches from the back of my 50mm lens to the front of my camera's housing(not the front of the +10) gives me a focus of 4 inches.

The lens' focus ring will not move the focus to this range, and therefore the whole lens must be mounted to some sort of moving platform. I'm hoping to be able to focus much like a telephoto 35mm lens with a smooth slide ring around a tube which moves the 50mm lens to and fro.

So, in short, this does indeed produce a much more optically perfect image, no grain, none of that, but introduces problems of allowing smooth focus adjustments on the fly. It would be easy to make an adapter that can change focus between shots, but to change the shallow focus while the camera is rolling when your character walks closer to the lens will require a more sophisticated structure.

Hope this helps, I'm going to continue testing housings to allow on-the-fly focus adjustment.

Spencer Houck

[Agus Casse]

Actually what spencer is doing is all another thing to the Agus35,...

He is still making the image in the camera CCD, so you wont get the same DOF of the SLR lens in a negative, he is still need to full zoom this dv camera to open the iris to the max and then adjust the focus.

With the agus35 you are creating the imag first in a Ground Glass, and than you just shoot that image with your dv camera, making in other words that your CCDS either you have 1 chip, or 3 chip camera, to be as big as a 35mm one to capture the full DOF.

[James Emory]

I ran across this looking at lights.

www.arri.com/entry/ggc.htm

[Peter A. Smith]

Spencer

I discovered that as well late afternoon when i stacked tiffen marcos up to +11. I have a sony trv 900, stacked the macros, rigged my version of the agus35. When i took off the GG i saw a full frame into the canon lens. Exicted, I started doing immediate test in my room using dolls for DOF and then compared pixels with the rig and without using photoshop and AF.

I found conclusive by,using a 28mm lens, i get the SLR len's angle of view, and DOF, but lose 1 1/2 stops.
However, when i tried to rack focus, i liked what i got from the TRV900 better. I know the 28mm is not great with narrow focus but i think it's more convienent without any lens rigged at all then what i saw.
When i deinterlaced and color corrected, I see a slightly diffused image from the SLR, but I have come to the conclusion that what creates much of the film look of the P&S and Agus's version is the GG. You need to have it because i was dissapointed in DOF and the quality was just the same as if I didn't rig anything at all but with light loss.
I have a Agus35 up and running but it cuts too much light and plan on making my own gound glass to shoot indoors. The quality of the GG is really important.

Peace

[Spencer Houck]

Agus, I may not be capturing the full DoF of a 35mm SLR, but if you've seen the video I linked to, I believe that the DoF is quite adequate. I'd rather have the clearest picture coming in...regardless of its "videoness" and "non-film" grainyness. Frankly if I want to degrade the image with grain, I've always got After Effects.

The two main steps, or barriers, I see between me and the almighty "film look" = lack of shallow DoF, and lack of 24p.

24p shall be achieved through post-pro (magic bullet, or vegas), and the DoF is seen in my test video, so theres the 2 barriers coming to a crashing end in my book. So i'm sittin' pretty at the moment.

Spencer Houck

[Bob Hart]

If anyone in Australia is into roll-your-own groundglass, there's an outfit in Victoria named Abasco Trading Pty Ltd Unit 19/12 Edina Road, Ferntree Gully VIC. 3156. They have Aluminium Oxide grits which are mentioned in another website mentioned here. I actually thought they were here because they were listed in the city metro directory yellow pages under 1800 809 228. They have local phone 03 9752 2816 and a fax number 03 9752 2808.

Nevertheless the rep was very helpful on the phone and happy to send a small order of 500gms across Australia for $10-00 item, $10-00 mailbag and GST $2-00, all up $22-00. He apparently normally sells to industry in bigger lots but was good enough to hunt for a broken bag to send a smaller amount and got it here in 1.5 days which is not bad.

[Bob Hart]

Some components and optical engineering principles incorporated in the Mini35 and Pro35 might not in themselves be furthur patentable individually.

The method and order in which all can be combined to produce a deliberate and new unique outcome is another matter. (I think the legal-speak word used in court the other day was "synergy").

A case alleging such an intellectual property is being used by a defendent without consent or licence, might be pressed by an aggrieved party as an enforcable right if that method is sufficiently unique as to not be a commonplace practice of combination of those components for any other purpose.

So be careful out there relating to patent rights as wisely suggested in preceding posts. There seems to be potential risk of liability both under national patent laws and under common law.

There are references being made to case law in the UK and Canada in a current matter in Australia so be aware the issue is very far from dead.

I am not a lawyer and am paraphasing from recollection some things I have stumbled across recently.

[Bob Hart]

Another lowlight test with groundglass CD dressed on a glass sheet with loose 600 aluminium oxide grit in water. - Much nicer uniform finish. No flicker. Image seems slightly softer, maybe due to denser opacity. Light transmissability appeared to be not as good as the pressed version. Quality across image was uniform with screen stopped or spinning. Spinning removed any faults in the groundglass finish.

Has anyone done any tests with test patterns? Mine don't look too good so far with merging in different places in the image at between 400 to 450 TV lines. DVCAM normally gives about 500.

[Louis Feng]

<<<-- Originally posted by Peter Sciretta : I'm lost in the past few pages of posts... we've gotten so far distracted from the original simplicity of this thread.

Some of these posts take someone with a lot of college science courses to figure out.

What happened to keep it simple??? -->>>

The principle has been the same, static GG or spinning CD. The simple version of the adapter is done, Agus has given everything you need to make one yourself. What Agus and some are working on is to improve the quality of the image and make it more useable, such as producing correct upright image, and hopefully will bring the result on par with mini35 or even better.

Technical problems:

1. Ground Glass. Quality is everything here, you need something not only fine, but also transmit more light.
2. Hot spot. Without solving this problem, you are limited to what kind of ground glass you can use and the image quality won't be good.
3. Producing upright image.

Let me state the progress so far (as far as I am concerned):

1. The 3 micron ground glass is at the border line of suiteable for the static solution. It's certainly suiteable for the spinning solution as well and using in the spinning solution will give you much better result. There is a good possibility that a material better than the 3 micron GG will be discovered in a few days, in that case this problem is resolved for static solution as well.

2. Hot spot problem. I consider this problem resolved. Refer to the static solution thread.

3. producing upright image. This one is solved in a few ways and the most efficient/economic way needs to be decided.

I think it's going well, and in a few weeks you should have something layed out with everything you need.

[Bob Hart]

There is another solution to inverting the image. Some night-vision intensifier tubes have a very compact inverter built in to a tube measuring about one and a half inches long by about one and a quarter inches in diameter with a display screen of 18mm (about 2/3 of an inch).

It is military tech so they are not exactly going to tell how its done in detail. The principle is they use fine optical fibres. These are packed accurately together so that along the entire length of the path, each fibre remains in its correct relationship with its neighbor.

Both ends of the piece terminate as a pick-up screen at one end and a display screen at the other. At the eyeball end, as I can work out there is a form of opaque projection surface superior to anything we have been evolving, or it may just be the polished face of all the fibres themselves.

To erect the diplayed image, it is pure simplicity. They just twist the mass of fires through 180 degrees. The doing of it probably creates incredible challenges in just keeping those fibres from shifting about. If an intensifier tube gets a strong (for an intensifier) light into it and goes into clear display, you can sometimes see little imperfections where a clump of fibres has moved slightly in relation to the rest. It shows like an earthquake fault line.

The CP16RA motion picture camera viewfinder uses a little projection groundglass screen - not quite true. The screen is about the thickness of a circuit board. It is actually a sheet of packed optical fibres, stablilsed I guess with some sort of tough adhesive, thinly sliced and then polished on both surfaces. The light transmissabilily of the viewfinder is excellent on wide-open lens aperture. Detail and contrast is crisp. (After getting accustomed to one of these, tube or LCD video viewfinders comprehensively suck to extremity.) With the lens stopped down, there is a weird diffraction rainbow effect. As we are after a wide-open lens aperture for best depth-of-field effect, this would not be an issue for us.

Optical fibres have come a long-long way since the early seventies when the CP16 became the king of news gathering.

If sufficiently fine optical fibres could be accurately packed in a wide round, glued, sliced and polished flat on both surfaces, it would be the ultimate groundglass. Maybe that's what the Mini35 uses.

I doubt a full CD sized panel would be workable for spinning. A more compact arrangement like a Sarich orbital piston, which works something like an orbital sander, to move a smaller screen might be possible.

If the fibre screen could be made with sufficient resolution that it would not have to be spun, then a pack of fibres twisted 180 degrees like inside an intensifier tube might provide a solution.

As a custom job it might be horrendously expensive however there may be somebody here who messes with fibre-optics who could put us right. Even better, maybe somebody here works for Electrophysics Company in the US, Photonis in France and Delft in the Netherlands and might ask some questions on our behalf.

[Taylor Moore]

Here is a work around to inverting.
A monitor that will flip the image on all axis.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3065860805&category=14946&rd=1

[Anhar Miah]

Taylor Moore man, i've already suggested that idea!

not specificially that monitor in question but about using an external monitor flipped upside down OR using an optical device that will flip the view finder of the camcorder

Either way at least you do not disturb the incoming image.

I also suggested using a "project box" someones seems to have imlemented that to.

I think the race is on to make a pro version that does not need flipping in post and a static GG version may well be nearing reality.

One more idea for you guys :

If you wnat to vibrate as opposed to spinning try connecting the GG to a small speaker and apply a sine high frequency signal to the speaker. My guess is that a very high frequency will be needed in order to minimise the grain, and aslo if you use 2 speakers one in the x axis and one in the y axis then you will have the grain movement in total random fashion thus remaoving any "streakes" which appear from either spinning of vibrating in one direction