Thanks for the encouraging words Keith. Much appreciated. So if I purchased an adapter - either EOS or Nikon - then mounted a 24mm F2.8 lens, what would you imagine I'd experience in terms of being able to focus on the Beattie screen? Will it be just a matter of experimenting with distance and diopters (macro elements like the hoyas I have)? Or am getting into the need for custom mounted achromats, etc? I'm hoping it's a simple matter, but I haven't seen anybody post exactly what they are using.

In your setup, what was required between your relay lens and GG (whatever the variety)?

Steev, it looks fantastic! Looks solid, easy to use and doesn't even like it will require rails.

So, I've been doing math, since I have no resources to do experements.

With Steev's progress on the ground glass element, this setup would be further enhanced without the need for the 16x and +10 macros, improving not only image quality, and erganomics, but visual ASTHETICS! which is what everything is about anyway right? In short, we need a relay lens.


With the nikon to xl mount, we can use normal 35mm lenses as our relay lens, i think our best option at this point for cost/ease of installation.

We need a lens that can see a 9.92in x 6.61in (7x the size of a 36mm x 24mm frame) rectangle. What that will do, is fit the 36x24mm frame right in the center of the lens, right where there is limited distortion from the wide angle. We need to be able to capture this size of an image within 1-6 inches.

Since I can't go out and buy these things, lens+adapter totals nearly $500, enter math.

If we know the size of the image we need to capture, and we know how far away we want it to be, then we can calculate the angle of view, and from the angle of view, we can calculate the focal length needed.
here is the equation we need:
let H be 1/2 height
Let D be distance
Tan A=Angle of view
H/D=Tan A

height=4.96 (1/2 of 9.92in)
distance= 3 in
Tan A= Unkown

this equals 1.65333 and ultimately 58.8 degrees
here is an exel spreadsheet that can do this equation.

http://sbirdsong.greatnow.com/35mm%20test/Angle%20of%20view.xls

if the rays converge right on the film plane, than we need a horizontal angle of view of: 58.8 degrees.

21mm=59.5

Basically, we need a 20mm lens for 3 inches.

Now one thing that I am not sure about, is where the rays converge. Is it inside the lens, on the film plane, or behind the film plane?

Without knowing this than I cannot calculate accurately. But I'm not 100% sure I need to, since the variations would only be a matter of an inch or two.

If the lines converge behind the film plane, then we can still calculate.
here is a diagram of how.
http://sbirdsong.greatnow.com/35mm%20test/angle%20of%20view%20diagram.pdf

Characters in red are unknowns.


Am I correct in assuming that if a 35mm frame could see the entire 9.92x6.61inch rectangle, than the xl1 ccd would see 1/7th of that, exactly 36x24mm?

One more question, do wide angle lenses usually have a minimum focus distance < 3inches? I would think so, but I've never used one.

Stephen

Update on Relay lens research. I went to a photo/video store yesterday and tried out a EF - XL adapter with a 20mm 2.8f lens (the wider, the less distance required, the better). They didn't have anything wider than 20mm. What I found was that I needed about 10 inches of distance from that lens and the Beattie focus screen on my adapter. Crappy. The entire adapter would be about 18 inches long. Very crappy.

So I think the EF adapter or Nikon adapter method is no better than trying to throw something onto one of the made-for-XL lenses really.

Now what I think is that a smaller lens is required, like the infamous C-mount lenses that I can't find any adapter for. Is there a C-mount lens to XL adapter? I'm thinking it's a custom job. Perhaps buying the relay lens from P+S Technik for $1500 is the only way to go? So I'm losing faith on finding a relay solution. But I'm hoping someone else finds the solution and posts where from and what to get and how they got it to work.

So, I went back to the drawing board and have a compromised solution. I decided that using the 16X IS lens is hack. It drifts out of focus, it's focus control is a joke, and I don't even think I'm getting the sharpest focus possible from it. So I broke out my 16X Manual lens again and overall, it's the better solution of the two. I can calibrate and fix the focus with the backfocus control, and I can get a definite sharp focus on the GG (focus screen) with precision and reliabilty.

http://www.holyzoo.com/111/xl2/35mm/images/HolyZoo35_Static_Adapter_37.jpg

http://www.holyzoo.com/111/xl2/35mm/images/HolyZoo35_Static_Adapter_38.jpg

So the issue is that I can't get rid of the Vignetting caused by going from 72mm to 55mm filter size. So I'm opting to just crop it in post.

http://www.holyzoo.com/111/xl2/35mm/stills/35mm_Still30.png
http://www.holyzoo.com/111/xl2/35mm/stills/35mm_Still31.png

I looked at test material on a TV and I can't see the resolution difference. Furthermore, the grain I was fretting over, is also barely noticeable on a TV.

So, has anyone out there found the holy grail of relay lenses without spending $1000+?

Cheers!

http://www.holyzoo.com/111/xl2/35mm/video/SnuffLeoTolo.mov

I am probably dumb or missing something here -- but --- if using the XL1's own lens, plus a macro?? why not build up an ALDU35 using 72mm filter rings and a 72mm groundglass, then stepdown to your SLR lens from that point forward?? Might get a hotspot problem if you can't zoom in close enough but there will be no vignette. If your 16x manual lens is not letting you zoom in close enough then of course 72mm rings are not going to solve your problem. The only solution may be to add a close-up lens on front of the 16x and that may be just as effective using the smaller diameter rings you already have.

For a direct relay path which eliminates the XL1's own lens, whatever lens you use for a substitute relay lens is going to have to have space added between the mount and the back of that substitute lens which normally fits into that mount, to bring the lens forward so it will focus closer.

Even a C-mount lens in a C-Mount to XL1 adaptor is going to need to be spaced about 3 or 4mm furthur forward. For the EOS lenses, there may be some sort of spacer accessory which would normally be used with the EOS camera to shift the lens forward for use as a macro lens - maybe???

If you have a 20mm lens and the EOS to XL1 adaptor, adding such a spacer should it exist, might solve the problem for you but you may still be up against an adaptor about 5 inches long.

That's not such a bad thing if you eventually decide to build a prism version to erect the image because that is about as long as the indirect path through the prisms from lens to gg has to be for the cheaper more commonly available prisms to fit.

If I am sending you down a blind alley then please accept my apologies in advance.

Steev, that video clip is freaking awesome! :-D

After a brief email exchange with Steev, I suggested (as a test) to use a CMOS/CCD lens as a "relay lens". They are small and inexpensive (every webcam/survailance has them)
and hold it in the XL's mount (by tape for now and obviously without the 16X mounted) (as an alternative to SLR 20mm for the same purpose) I did not test them yet, but I guess a 6 , 8 or 12mm will do.
Note: most web come with 3.6 or 4.2mm lens (so wider than ideal for this application. Might distort the image and/or not give you the full brightness to cornes from Fresnel/GG if you move too clos e to GG as to fill the screen.

When you can get a clean image of a B Card with a recangle 24/36mm (or whatever size you can use from medium Beattie about 32/45mm?) than all you need is the XL male mount (as from the 16X lens) to mount them on the camcorder and hold them together.

The "whole adapter" would be : Prime lens (Nikon? or else) 46.5mm to GG, XL mount and (inside) lens for the CCD.

This is (IMHO) the most efficient way to get the "look" without going too "hard" on the XL's mount (to support the extra weight) and without a "need" for rods. (unless you need FF or remote focus)
I would be happy to hear a sucessful test came out of this.

I'll second that "freaking awesome!" comment about the vid... Steev, great stuff.


For some time I've thought that doing an a spinning GG option would be easier to do then a static one--- I'm still not 100% sure that it is not the case but Steev, you've been doing some fantastic work for everyone!!!!

Well, I keep getting rejuvenated spirit. Glutton for experimentation.

Bob, I thought of going up in GG diameter but with Beattie screens, that is wayyyy expensive experimentation. I feel that going for a different relay lens is the way to go. I can only dream of getting the prism version going (which means forgetaboutit - I'll end up buying the P+S by then after finishing projects with my home brew).

I ripped apart 3 video cameras yesterday:

www.holyzoo.com/111/video/ZoocamMovie_01-15-05c.mov I think this sums up how much work all this is.

I extracted their lenses, and only one resulted in an image that I could get by holding it up to the XL2 CCD and holding the GG up to the front of the lens. To be blunt, it looked like shit. I think the CCD of the camera from which I snagged it from was 1/4".

So I'm in the process of fetching/looking for higher quality c-mount lenses on ebay.

By looking at BHphoto, I'm learning that these lenses come in 1/4" all the way to 1" My first guess is to go for 1" 25mm or so. If I go with smaller lenses, my question is does the requirement for focal length move towards wider or more telephoto? For example would a 1/3" need to be more like a 8mm? This is where I'm lost, in the dark.

If I find a c-mount that works with test positioning, I'd get an adapter built to mount on to the XL mount.

My other concern is that these C-mount lenses will require a smaller diameter GG (focus screen) when I've already invested in a 2" width format.

Who knows......

Steev,

can you tell me what codec this clip uses - i can smoothly open and play your other clips but not this one.

http://www.holyzoo.com/111/xl2/video/XL2_CO_.6Wide_Test6.mov

thanks,

filip

p.s.

your film in park with kids is just amazing!

Filip, that clip is in DV50 codec. It may not play very well in a browser window, but should play fine in quicktime player or final cut pro in a sequence set to DV50 codec. I'm using DV50 after 4:1:1 Color Smoothing in Final Cut Pro to get rid of DV25's awful handling of reds, etc.

Thanks for the kudos! The kids in the park was a standard Canon XL lens, which reminds me - non 35mm imaging is great too!!

Steev... you are a madman. LOL!!


Great vid and I'm happy the bunny made a cameo---

Steve, have you tested this footage on a 16:9 tv? HD for instance? I'm interested in how obvious the grain is when blown up to TV size.

Aaron, I don't have an HD TV or large TV. If you have such a TV, I can post a DVD image that you can burn and play on a DVD Player on your TV.

I guess I haven't been driven to test it like that since I've been critiquing the footage on an Apple 23" Cinema Display (no slouch).

*Steev Ramble Time*

I was watching music videos on FUSE on digital cable last night and thinking about how much fast cutting and movement is going on and with intentional grain/noise introduced, and was left thinking that for that kind of work, this level of optical quality is cool cool cool. For a short film with much slower pacing and lots of money thrown at the production, lights, props, talent, and crew - I'm not sure how I'd feel about relying on this homebrew method. The subject would have to be experimental where imperfections are more than okay since it would be more about "hey we have this grand idea and know how to communicate it, so here it is". I'd guess audiences will concentrate on the story, the acting, the editing, the energy, not whether they saw slight grain blowout on brighter out of focus parts of the image, or if that spec of dust over here and there. And like any gear, it would be crucial to know what's going to look good given the medium, and what will look bad. Am I rationalizing? Yup!! :) I'll be working on some short pieces soon and perhaps I'll post them, including burnable DVD image, so it can be critiqued.

Hoping that a low cost moving glass invention surfaces some day,

steev
www.holyzoo.com/zoo_updates.php

Thanks for the info Steev :)

BTW, does anyone know why highlights tend to blow out when using these adapters? It really bothers me at times!

I just noticed that there was an XL2 thread started.... it looks like our effort to focus all the XL development (since the XL1 and 2 both use the same lenses and adapter) is getting spread out again.

Kevin, as background, I didn't start the XL2 thread, but have posted a bunch in it, and some posts in this one.

However, starting reading from scratch on this thread has been painful for me. Don't get me wrong - this thread has been crucial research, but my question remains - who has had success on this mission? And where are some summarizing applications and documentation?

Could there be a new thread with detailed successes posted at the top to begin with?

don't get me wrong... it was my suggestion that prompted the consolidated XL1 thread--- the idea of reading all the way makes my brain bleed too.

I'd love to start a new thread for new ideas but it never seems to work out that way.

You are the man of the hour Steev, you are currently our best hope for a successful design at the moment so whatever you say goes but I just hate to see people running around in different threads duplicated work being done elsewhere when we could all be working together.

I'm still amazed that with all the XL model cameras out there that we haven't been able to get a solid design and further along with an Aldus or an Agus 35 option... but unfortunately my brain isn't good for this sort of thing. I've got ideas but just not the hard core tech skills to build with.

I'd just love to have us get something going and I've been hoping that the XL2 coming out would envigorate the efforts.

Amen.

Brain Bleed - Yes. :)

I see your point - I'll shift my posts to this thread in the future instead of the other one.

Again, this sums up what I've gotten to work to some degree:

www.holyzoo.com/zoo_updates.php

For one, I am surprised there are so many threads. I think we should take a more modular approach. The adaptor segment from 35mm lens through GG should really be interchangable, all that should differ is the registration length to focus different lenses on the GG. Assuming this is done correctly, it should always result in an identical imaging area on the GG.

The segment from GG to camera is what differs from camera to camera, based on the camera. The variables are the minimum focus distance for each camera, and what length spacing and macro lenses may be necessary to focus on the imaging area, and any step-up/step-down required.

I am up for any ORGANIZED and easily understandable approach to an XL sollution.

I'm going to bump this up and try and get some movement again on the XL 35mm adapter front....

I saw the newest version of the Mini-35 at DV EXPO in NYC last week and had a nice long chat with the foiks from ZGC and got to play with it and saw all the new bells and whistles from the original spinning glass version. Great stuff. They also mentioned that new unit is going for about $10,000.00 for the XL cameras.