Consolidated XL1 35mm Adapter Thread

[Stephen Birdsong]

I'm sorry to have suddenly disappeared, I've been traveling, now I'm moving out of state, so once I'm settled, which shouldnt be too long, I'll be back in business.

stephen

[Keith Kline]

Hey Dino a page or 2 back you mentioned a source in the UK for a cheap EOS to XL adapter. Do you have any info on that or if he has any available and for what price? I'm working on building my own eventually. I have a milling machine now, just waiting on the lathe and eventually plan on making my own someday, but until then I'm in the need of one to finish my agus35. Thanks for the help.

[Steev Dinkins]

I've been reading these threads for the last month and a half, and now attempting to construct a static adapter based on James Webb's.

www.enormousapparatus.com/static03.htm

I have seen first hand, the ground glass projection concept using a Hasselblad Screen, and I'm very impressed. Here are some video clips of the test. Shot with a GL1, not my XL2 yet.

www.holyzoo.com/111/video/XL2/35mm/

So here's my problem. I am trying to use an M42 lens and adapt it to 55mm threads or any other standard filter, but hitting a brick wall. It's not a standard thing to afix an M42 lens to anything other than a camera body.

Does anybody have any suggestions on how to achieve this. Alternatively, what would be the easiest way of mounting a 35mm lens to this 55mm (or other) element chain? I haven't found any Bayonet to thread adapters either. BHphoto, Adorama, and various other places have basically told me that it doesn't exist.

Am I to go consult with a machinist at this point? Yeee hawww, this is a crazy ride.

steev

[Stephen Birdsong]

I am moved, but definately not back in business. Things here have not gone as planned. I got burglarized and some scumbag is the new owner of a DSR-40. I also have one of those landlords that you think only exists in movies. So, unfortunately, my work on the relay lens is all but completely halted untill my life gets back in order. I hope someone else runs with the torch.
I still think the xl1/xl2 is the best candidate for a static/vibrating 35 adapter. Its unfortunate that its the least worked on (or at least documented) for the adapter. Hopefully, with the popularity of the xl2 increasing, more people will join the effort and we can actually see some progress.

All we need is to figure out how to build a quality relay lens, then we can join the discussion for a non camera specific generic adapter.

Stephen

[Kevin Burnfield]

Damn... sorry to hear about your loss, Stephen.... hope you had renters insurance!!!

Yeah, I still think that an XL1 / XL1S / XL2 solution would have a LOT of interested people but it just can't seem to get off the ground like a lot of the fixed lens DV cameras options did.

[Bob Hart]

Slightly diverging but hopefully still on-topic, the Electrophysics Corp Astroscope intensified night-vision uses a relay system for the XL1/XL2 in principle similar to P+S Technik's arrangement.

The Astroscope relays a 2/3" diameter intensified tube display which is about one quarter the image area of the 35mm motion picutre frame by the time you crop the circle to make a 4:3 frame within it.

In developing a relay for the Pyser PNP into the PD150 I used the SW5042 lens set to relay a 2/3" display. With closer spacing between the front element of the camcorder and the relay lens and from relay lens to groundglass, I was able to use the same lens set for an Agus relay.

It might be worthwhile enquiring to Electrophysics Corp for info on how they mount their relay optic relative to the XL1/XL2 lens mount.

[Sarena Valilis]

<<<-- Originally posted by Bob Hart : Slightly diverging but hopefully still on-topic, the Electrophysics Corp Astroscope intensified night-vision uses a relay system for the XL1/XL2 in principle similar to P+S Technik's arrangement.

It might be worthwhile enquiring to Electrophysics Corp for info on how they mount their relay optic relative to the XL1/XL2 lens mount. -->>>


HI Bob Hart


I took a look at their relay, but i think that it has a ccd and some electronics inside rather than being a straighthru lens arrangement.... so, not really what we need here....

[Stephen Birdsong]

Bob,

do you have a retort for that last post? Or do I need to do some research?
I have a feeling that the ccd is only for the night imaging, but feelings are not very imperical.

Stephen

[Steev Dinkins]

Here's an update to my work on a static XL2 adapter.

http://www.holyzoo.com/zoo_updates.php

Now I'm wondering how to make it work with a relay lens other than a 16X IS. The IS lens for this use is definitely sketchy and unpredictable.

Anybody have any experience with relay lenses on the XL1/XL2?

[Keith Kline]

<<<-- Originally posted by Steev Dinkins : Here's an update to my work on a static XL2 adapter.

http://www.holyzoo.com/zoo_updates.php

Now I'm wondering how to make it work with a relay lens other than a 16X IS. The IS lens for this use is definitely sketchy and unpredictable.

Anybody have any experience with relay lenses on the XL1/XL2? -->>>

I just check out your new footage, it looks really good. I liked the other clip you linked before with the dolly shot, but it seems like your new set up is working even better than that. Makes me want to reconcider my rotating GG adapter for my XL1s.

It doesn't seem like the relay lens talk is as hot a topic as it's been in months past. I still would like to figure out a better system for it. Currently I am using the Canon XL to EOS adapter. A friend had one and their camera is in the shop, so they let me borrow it to test relay lenses. I just got a benchtop milling machine and a benchtop lathe is on the way soon so eventually i'd like to make my own adapter to mount the relay lens, but for now the canon model works. As for the lens itself... I'm using an off brand EOS fit lens. It's a 24mm F2.8 lens.

Right now I'm working on a rotating GG adapter, using the cd motor and such. I hope to get it working in the next week or so to start working the bugs out in it. After seeing your progess a static adapter might be in the works as well.

[Steev Dinkins]

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)?

[Kevin Burnfield]

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

[Stephen Birdsong]

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

[Steev Dinkins]

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/...Adapter_37.jpg

http://www.holyzoo.com/111/xl2/35mm/...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/...mm_Still30.png
http://www.holyzoo.com/111/xl2/35mm/...mm_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/...uffLeoTolo.mov

[Bob Hart]

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.