Consolidated XL1 35mm Adapter Thread

[Mike Tesh]

An idea. What if every XL1/2 user reading this signed a petitioned to a company like Sigma. It would outline that we want them to build a lens for the XL1/2 that contained a ground glass element inside it. Something close to the size of a 35mm frame. Behind that a relay lens. A single lens solution.

It still wouldn't solve the viewing problem but that could be temporarily solved by flipping an external LCD.

[Kevin Burnfield]

Josh, this is the sort of thing we need to get rolling---- I'm like Roger and not too mechanically minded but there are people here on this board who are geniuses in this area. Just read some of the other threads in this area, it makes my brain hurt these guys understand this stuff so well.

From what I gather it would take a VERY FEW number of people together to get a machined adapter made very inexpensively.

[Mike Tesh]

Ok let me explain this idea in better detail since I just kind of touched on it earlier.

It seems to me that of all cameras the XL series has the greatest advantage to being a system that can obtain 35mm DOF characteristics. Which is probably why the Mini35 was first presented with the Xl1.

Now the mini35 is one solution which allows you to attach nearly any kind fo 35mm lens to it. It then rotates ground glass and the image and send it through a relay lens to the CCD's on the camera.

In this regard its a great camera for a professional engieer to build off of. But for every day folks like us here it's a problemchild since the native lenses are so large and finding a relay that can hook up to it would also need to be engineered.

This idea is to petition a company like Sigma to build a single lens solution. Where the front of the lens is your standard 35mm lens elements that then hit a static ground glass element of a certain size. Say 24mmx18mm. Then a small relay lens to bring that image into the cameras CCDs.

All of this within a single lens barrel as if it was just a lens itself.

There are two benefits to this that I can see.

1. The lens can be designed to fit the ground glass. Which means the flange to focal plane distance could be shorter, better optimized, ect.

2. The company in question could sell multiple prime/zoom lens at various lengths/prices. It wouldn't be a one adapter fits all solution but and entirely new series of lenses. All they would need to do is start with one prime lens to test the market. If It sells well, if they already knwo there are people wanting to buy it, then they could find themselves in business making a variety.

Now I don't know whether it's possible for a company like Sigma to do this or not. It would certainly take some R&D funding. It would also mean you would have to find your own way to flip and image. That is an easier to solution then the lens itself as it can be done electronically with various LCD screens. But the XL mount has been around for close to 8 years now and carried over 3 cameras. If the trend is for Canon to stay in the 1/3 chip range on future XL cameras then there are more cameras to come that support this lens mount. Plus an existing market of people over the last 8 years.

The way I look at it is like this. Even if it cost me $600-700 dollars for a single 50mm prime that can do this then it's worth the money. Because it's still a tenth or so the cost of a Mini35. And for people like me a mini35 is not an option with that much money that needs to be put down at one time.

[Mike Tesh]

Here is the petition I am about to start. Please correct or help me clearify if need be.

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To Sigma

We the undersigned seek you out as the world's largest independent manufacturer of lenses. We are owners and users of the Canon XL series of digital video cameras. The XL1, XL1s and XL2. All of which contain the same lens mount.

We are seeking you out in the hopes you will build for us a lens or series of lenses which can display the depth of field characteristics of a 35mm camera onto a digital video camera.

This would be a lens that contains a fine ground glass element inside it. This finely ground glass then acts as a screen for the larger image coming from the first series of lens elements. An image that would then be focused onto the XL series 1/3 inch CCD imaging block via a second series of lens elements.

We understand this would require us to rotate our footage 180 degees for proper playback and viewing. But this is insignificant in comparison to the task of engineering our own lens system.

We are professional and independent videographers, filmmakers and hobbists. We need your help.

Thank you

---------------

[Stephen Birdsong]

I don't think it is a bad idea, although I would form the letter a bit different.

Instead of saying you want them to do the R&D, you could say that this had already been achieved. What we are looking for is a manufacturer who can pruduce uniform lenses with precision and high quality components. Something that would improve on an already successful design. That way, we are contracting them for their manufacturing abilities, not for their engineering (the most expensive part of a lens).

Explain specifications of the lense generally, don't necessarily mention its purpose or application:
a lense with the xl lens mount, a "relay" lens that is capable of focusing on a 36x24mm frame at a very close distance (under 3 inches, the closer the better) with a pcx condesor lense between relay and gg, then a nikon or canon lens mount at the correct flange depth from the gg, if the gg was considered the film plane.


Include that we would be willing to pay up front, and buy in bulk.

We don't need them to manufacture prime lenses for us, we can use nikon or canon lenses. OR pl mount, using cine lenses

cine lenses are something I personally don't want to use at this point, mostly because of cost, but possibly in the future.

I think it would be important to write it in a way that makes them think this is feasable and simple for them to do, and a way for them to make a profit. Exclude information they don't need to know ie: flipping the image, pleading for help etc... approaching them as professional clients expecting a professional response is important, we want the manufacturer to take us seriously.

their costs=
xl mount
relay lense
condensor lens
ground glass
nikon mount
construction costs
if they make them in 100 or so quantities, i bet it wouldn't be too expensive.

Since they make lenses, not much R&D is required. This is a simpler process than making an slr, as there are no mirrors involved.

I think we need to keep the xl 35mm threads in once place to get the momentum moving again.

I feel like my creativity has been stifled since I got it in my mind the idea of achieving 35mm dof, now I don't want to shoot, but I haven't gotten a functioning adapter (mostly because of lack of funds and time)

my 2cents
stephen birdsong

oh yeah, lets hear who would want to do it and how much its worth to you.

[Mike Tesh]

What you are suggesting is for them to build us mount like a mini35.

The idea above is for them to build us a lens or series of lenses specifically for the XL1. Where the ground glass is embedded inside each lens sold. Since they are lens builders I would think this is something more along their lines then just a generic mount convertor with ground glass element.

But I'm willing to be open minded about it. If an adapter would be ultimately more successful and easier for them to produce, then that is the route to take. Perhaps we should suggest to them they use their proprietary Sigma mount on the other end rather then a Canon or Nikon mount. After all they are trying to sell their Sigma lenses on their own mount. If they knew they could tie us in with their lenses on our video cameras then we'd be more likely to buy their Sigma SLR cameras for our still work.

I do think we should tell them what it will be used for. After all they need to know what the goal is or how would they test that it is working properly.

I don't think this should be approached as a one time deal for a limited order. I think it should be approached as an entirely new product to be sold to the general public.

[Stephen Birdsong]

Ok, check out the post by mike tesh, lets put our heads together on how to arrange manufacturing and see how many people would be interested in going along with it.

This is something I might be willing to spearhead if need be.

I'm going to try and get a sample of my progress up today..
We shall see if it is successful, I have to assemble my set-up again outdoors and my gg substitute is of pretty poor quality.

but its something, I figure we gotta start where we are and move on from there.

stephen birdsong

[Jeff Donald]

Big problem, they (Sigma or whomever) would have to license the lens mount and other technology from Canon. Canon is very, very, unlikely to grant another company license to their mount etc.

[Stephen Birdsong]

ok, so I threw something together. funny thing is, after setting up for bout an hour trying to get it to work properly, right when I start rolling, my roomate walks in the door, so thats what you get to see.

here is it is:
http://sbirdsong.greatnow.com/35mm test/35mm test 1.mp4
be sure to have some sort of pop up blocker, because this web host blows.

there is some weird green discoloration, thats because there was alot of open air between lenses, and it caused a real hazy lens flare.

Anyway, its super soft because of many reasons, the first being that my gg isnt really gg, its hollywood frost and just isnt sharp enough.

the chair was about 72 in from the film plane, and I have no idea how much of the "gg" i captured. It is pretty narrow though.

my "prime" is 50 mm, and my relay is 50mm (not even close to being wide enough) but thats all i have at the moment, so thats what we get.

stephen birdsong

[Mike Tesh]

Jeff how is it that Sigma gets by making lenses for the EOS system? Or for that matter how did that 14x Fujinon lens get fitted to an XL mount or the relay lens for the mini35? All of which have been sold commercially to fit the XL series cameras.

I'm not saying you are wrong by any means. You would know more then I.
I guess if worse came to worse we could petition Canon themselves. I justed figured that since they already had XL lenses on the market they would want to sell those first.

[Jeff Donald]

Sigma licenses the EF mount from Canon. However, they choose not to buy the chips in the lens from Canon. That is why Sigma lenses at times need to be "re-chipped" in order to stay compatible with Canon EOS camera bodies. The Fujinon lens was modified after market by Optex if I remember correctly. The mini-35 is probably an after market modification too. You can buy the mount, but the chips are more of an issue. Too small of a market to spend the R & D to make your own and Canon probably wouldn't sell their chips.

[Mike Tesh]

Well that certainly makes sense. But it's still worth a try. I'm not after an AF lens myself.

[Kevin Burnfield]

Stephen, can you post some pics of your unit as well???

Don't know where that green cast is coming from--- but you can see the DOF happening.

Considering that not only the XL1 but now the XL2 would use the same adapter I'm absolutely positive we can get some people together to go in on a group buy.

[Stephen Birdsong]

yeah, tomorrow I shall try again. I ran out of sunlight, so tomorrow I will start earlier. Ill take pictures too.

the green haze is coming from stray light mixing between lens stages. you'll see what I mean when you see pics.

Stephen

[Stephen Birdsong]

ok i did an expirement, a little better done this time.
pictures of setup, and comparisons with normal lens.

im adding some text to the pictures and I gotta figure out a good way to show them, maybe throw together simble html file...

will be up soon..

stephen birdsong