I really want to get started with building a 35 mm adaptor. But I have the canon XL-1 and I believe that using another lens than the original one would be the way to go. Both considering the cameras length and quality of image. It would be really nice with a relaylens which is made for the focusdistance to the GG.

Have anyone found a relaylens that works? - or a better solution??

Thanks

Hello Anders

I guess what you need is a macro lens which can focus on a ground glass

try this

Optex UK make a Nikon lens mount adapter (LMNIKXLC) to which you cound attach a 55mm Nikkor Macro lens plus maybe an extension tube (say PK13) so that the image size is about right

that should do it

Hey John - thanks for the quick reply.

I actually got a Canon-EF adaptor with the camera when I bought it. But it has the 7x magnification . Do you think it would work anyway?

If anything that 7X will work to your advantage. Remember you need to be able to focus on a section of ground glass measuring at the most 36mm X 24mm.

-Brett Erskine

There is no 7x magnification in the Canon adapter.

There is also no lens in the Canon adapter.

The Canon adapter lets you put Canon still lenses on your XL1. The idea of the 7x magnification comes from the fact that the 35mm still-camera frame is about 7x as large as the 1/3" CCD's in the XL1... or, in other words, you'll see 1/7 of the full frame. So the "equivalent" focal length of mounting the Canon lens on your XL1 would be like as if it was 7x as long... i.e., a 100mm lens, when mounted on the XL1, will provide a field of view equivalent to a 720mm lens on the 35mm camera.

But there's no magnification going on. It's just seeing a smaller window through the lens.

A 24mm still-camera lens, for example, when mounted on the XL1 using the Canon adapter, will give you the exact same field of view (and depth of field) as if you just put the Canon 16x zoom lens on, and zoomed it to 24mm.

Now, back to the original question: yes, you want and need a relay lens. That's the way P+S Technik designed the mini35, and it's the best way to go for what you're talking about. A dedicated optic that closely focuses the 24x18mm frame will give you the best results.

I have the Canon EF XL adapter and it does indeed have optical elements. The adapter does impose a 7x image size change and it may impact your DOF. If I want my subjects head to be the same size I will need to be further from my subject, and that will effect DOF.

Fascinating -- I should have said "I don't think the EF adapter has a lens..." Sorry for the mistake.

But: I still question the idea of 7.2x magnification being a property of the adapter. If you use equal zoom length on your stock lens, or on your still-camera lens, the field of view and distance to subject should be the same. A 50mm lens is a 50mm lens, regardless of whether it originates on a still camera or a video camera.

Your point about matching subject size is perfectly valid as to why it would affect DOF, IF you're trying to match subject size between a still camera and a video camera. The still camera has a much wider field of view, and needs correspondingly more telephoto optics to provide a similar field of view.

What I'm saying is, does the adapter have any effect on the still lens itself? I don't believe it does... but nothing beats verifiable testing...

Let's take the longest end of the lens as an example. The 16x maxxes out at 88mm, so an XL1 at max zoom, or an XL1 with the EF adapter and a 90mm lens, should deliver the same field of view, the same subject size, and the same depth of field. Do you have an 85mm or 90mm lens that you could test that supposition out with?

Thanks!

I've bought an F2 24mm SLR lens for use in the adaptor I'm developing, distance from the front element to the 36x24mm image is around 14cm, I'm hoping this is more than workable (prism and mirror should cut down the physical size).

If you've got the money, try finding a 20mm F2 SLR lens. Fully wide-open these fast ultra-wide angles will be a bit soft, but the more stops of light you can salvage the better considering the nature of these adaptors.

the is the toughest part to figure out for the xl1s. and this is the reason, any of your lenses you use goes through what is called as the multipler effect. That is it icreases the lens properties to somewhere around 1.5-1.7 roughy. so say you, take off your factory lens (16x or 14x) put on canon xl1 mount to, say a nikon fitting (going nikon is the cheaper route like $180USD right now at Les in the UK). so you get a fast cheap 55mm lens that opens up fast (f2), when you put it on your camera it will act like an 80mm lens-this focuses in much to far on your ground glass. so what you want to get for your relay lens is get the widest and fastests you can afford. like a 24mm f2.8, when this is put on it acts more like a 35mm because of the magnifyer effect. you will also want to try and get one that can fit a 52mm lens filter. as you will see how useful it becomes later as a connector to the rest of the unit.

the ideal meduim you'll be housing will be 2inch diameter pvc connectors, they fit 52mm filters amazingly well and centered.

for the magnification at say, 24mm, you only need +3

Dino has been working on an XL1 solution for a while now but hopefully those of us with them can put our heads together with the rest of the folks here and come up with a less expensive option.

Barry, the magnification comes from the size difference between 35mm film and 1/3 inch CCD. the difference as measured horizontally is 7.2X. Why does this change DOF? Think of the lens as projecting a circle of light on to the CCD or 35mm film. The circle has excess coverage when the CCD is placed in it's path. Compared to 35mm film, the CCD only sees the very center of the circle. When the image (either captured on film or electronically) is enlarged to a fixed size (TV monitor or print) The smaller format will show a higher degree of magnification. Why? Remember the smaller format only captured the center portion and when enlarged to fixed size the center portion is enlarged a higher percentage to fill the fixed size (size of screen etc.). In the case of the Canon XL1 with the EF Adapter, the degree of enlargement is about 7.2X This is a problem when you try to fit a subjects head into the fixed size. You end up having to back up to get all the subject in the frame.

as far as how mine is built, although i have an extra filter protecting my gg, and i'm not using a pl mount (nikon still), but it's adjustable from the relay to the achromat and from the gg to the prime lens... i've got a holographic diffuser model i'm working on next. the quality is already pretty damn amazing, esp. in low light, i just picked up a fast 17mm i want to try as my prime lens and see the results, but here are schematics i've kindof updated...

http://www.dinoreyes.com/images/xl1_deluxe_aldu35_new.jpg

the most expensive are the two lenses then the canon lens mounts that attach, everything else can be bought for less than $175 and put together with very accurate but not extensive cutting then cementing and painting...

I noticed that you have, what you call a "achromat" behind your GG where most people are using condenser(s) (also known as a plano-convex lens - PCX). Would you please decribe the shape of the glass your using. Is it flat on one side and curved on the other? Or is it curved on both sides (at equal ammounts)? Thanks. Nice looking diagrams by the way. May I recommend you add a plain UV filter between the PL mount and the adjustable focal length tube. The reason being is it will keep dust and hairs from coming in contact with your GG and ruining your shots. Of coarse there are many other changes if you want to add EXTRA features like tilt/shift and anamorphic glass but as a "base model" it is a very accurate representation of the design I've been describing in words on this thread.

this is closer to what i've made

http://www.dinoreyes.com/images/lens_xl1_v4.jpg

what i am using instead of a condensor lens is an acromatic diopter (50.8mm), it originally came from newport optical? reg. like $140, but i got it off ebay for $40 new. condensors lenses (also, i believe called singlets/simple lenses below) are around $30

go to this article:

http://www.edmundoptics.com/TechSupport/DisplayArticle.cfm?articleid=267

now read Application Primer #5 at the VERY bottom....

What is an Achromat?
An achromatic lens consists of two optical components cemented together, usually a positive low-index (crown) element and a negative high-index (flint) element. The additional design freedom provided by using doublets allows for further optimization of performance not possible with singlets. Therefore, achromats will have noticeable advantages over simple lenses

Achromats have better accuracy and color correction but the are more expensive. But for sizing make sure for either condesor lens or achromat get a 50.8mm. Find also, an extra 52mm filter with the glass broken or popped out, they are good frames to hold these lenses in. It is flat on one side and slightly curved on the other

As you notice Brett, i also got the UV filter to protect the gg as you had previously suggested...

-d

Dino,

As has been stated in this thread and all over the forums, the CCD sees 7.2x less than a 35mm SLR camera does through the SLR Lens. So a 55mm lens on the XL1 will give the same FOV as 400mm lens on an SLR and a 24mm lens on an XL1 will give 170mm equivalent.

Where exactly are you getting this 1.7-2x multiplier effect number from?

here be a brief description...
http://www.lonestardigital.com/multipler.htm

and, sadly, a partial article here...
http://www.digitaldingus.com/articles/fov/fov.html

but surely a 24mm to 170mm is a sea of difference
making my aldu35 impossible for use, but it seems
to work well!

7.2x seems rather extreme, but the EF adapter does
come with a small, 30mm condensor lens, perhaps
that little guy is the culprit(!?). But if you use a canon to
nikon or pl adapter they don't contain those lenses,
what they do do is that push away the lens around
3/5 of an inch, something like an extension tube you
would use for macro photography, only just a bit, so you
have the tinyiest "magnification effect." like not quite
100% but more like 50-70%.

I've been struggling with this problem as it is a big
xl1 issue. i was considering consulting with an expert
but the costs were astronomical for the amount of
effort i considered...

or something like that,
d

Dino, both of those articles in the links reference dSLR chips which are much larger than the 1/3 inch chips used in the XL1. The 1.5x to 2x magnification (crop) factor quoted in the articles is in reference to the larger chips.

hmmm, well I know for sure the xl1 CCDs pick up only a portion of the image, like so:

http://www.dinoreyes.com/images/frame-comparison.jpg

this is a given. so it is my reccommendation to go as wide and fast as possible for the relay lens, because you are really just shooting the gg about 1.75 inches from glass to glass, you wont have any trouble with vignetting because using a 52mm filter setup, there is plenty of "wiggle" room on the gg.

If you can focus the image of the groundglass onto the CCD's the system will *work* regardless of the focal length of the lens, but the depth of field qualities of the 35mm imager size will be lessened the smaller the area of the groundglass the CCD's see.

If the focal length is so long that you only see a very small portion of the groundglass you'll effectively be doing nothing put putting more glass between your subject and your CCD's and gaining no depth of field shortening (not to mention the loss in stops).

The Canon EF adaptor does indeed have a 7x magnification effect (Canon state this) and any mechanical adaptor will inflict this same penalty.

Really, as far as relay lenses go for the XL1, projecting the entire 35mm groundglass imager to the CCD's will be tough, you'll either need to use very wide and fast lenses (<24mm), like you said, or have a very long adaptor with longer more affordable lenses. The later not being a very usable alternative. We can of course compromise and still have a system which works by capturing less of the groundglass image.

As I've said before, with a 24mm relay lens you'll need about 14cm distance between the front element and the groundglass to capture the full 35mm frame (less for a 35mm motionpicture frame). Compressing the system length and optical path will leave you with less field of view and more depth of field, you can shrink it physical and retain the same optical pathway distance if you use mirrors however (you can also erect the image killing two birds with one stone).

We don't have to build these systems to any standards but what we personally think is good enough, so if you don't capture the full frame and it still looks good enough for you, then it's a job done!

Thanks for all the great info guys! But now I'm REALLY confused! How do you think the Mini35 relaylens works?? It has to be a really wide and fast lens - or what? Anyways it must be possible to make something similar somehow!???

Their relay lens costs about 1500 Dollars and the other solution could easily end up costing the same! I really don't know which way to go now!

Thanks

Put the UV on the right side of that extension tube so that you throw any dirt COMPLETELY out of focus to the point of disapearing.

-Brett

Left side (next to the PL mount). HA HA Whoops

-Brett

I don't know what FL or speed the mini35 lens is, but I expect it's probably a around 15mm <f2.0.

Remember the stock Canon lens will do this in a full 16x zoom lens and making a prime is much easier.

Using wide angle SLR lenses as the relay lens is overkill really, since they are designed to cover 7 times the image area that we're using. A professionally designed prime lens made especially for the job will do it much better and that's what the mini35 uses.

If you can afford the 1500 for the relay lens, buy it! It'll do the job perfectly :)

I have yet to find an alternative which is perfect for the relay lens, the best options are wide-angle and fast SLR lenses. The problem is the FFD of the XL1 is similar to that of an SLR but the multiplication effect makes SLR lenses a poor choice for wide angle work. And at the same time most CCD based camera systems use the C/CS mount system which has an FFD completely incompatible with the XL1. There are plenty of very wide CCTV camera lenses which can never be used with the XL1 despite the fact the cameras uses the same size CCD's.

Further to my earlier post, I dug up the macrophotography formula as

u = F.(M+1)/M

where
u = distance of object from lens
F = focal length of lens
M= scale of reproduction

for the full frame 35mm gg, M~1/7

which means that

u = 440mm for a 55mm lens, and
u = 200mm for a 24mm lens

neither of which lends well to a short form factor, furthermore a f1.4, 24mm will eat money

which leads me to a better solution ???

1 buy a broken Nizo 2056 S8 camera from German ebay (they have tons of them) with a clean working Schneider 7-56mm f1.4 macro zoom lens and carefully remove it

2 buy a cheap Canon standard lens with a mount compatible to your existing adapter and remove the bayonet mount from it

3 find someone (maybe a good camera technician) to fit the Canon mount to the rear of the Schneider


total cost should be under 250 euro and would allow the gg to be within u=50mm of the Schneider and the image would be razor sharp


good luck

So maybe i'm not really good at talking about all this lens stuff. but after sometime of thinking about it i figured out how to build an adapter that seems to work well, (haven't had time to really test fully yet). it requires almost no cutting which is amazing and allows for screw adjustment. so i finally got around to taking some pics of the Aldu35 for xl1/xl1s so it goes like this

here is a pic with the unit mounted...
http://www.dinoreyes.com/images/cam1.jpg

it's still all unpainted pvc with simple hot gun glue...

this pic has the parts broken down and exploded out with another model i'm building that will be using a hologrpahic diffuser and a condensor lens.

http://www.dinoreyes.com/images/cam2.jpg

above you will notice a complete one all screwed in and glued, with the lenses dismatled

below are the parts (2 inch pvc connectors) roughly numbered in the order they are arranged, those filters are 52mm. on connector #9, the dotted line shows where i cut it to glue on the prime lens mount. all you need is a cheap dremel tool and it will cut through that plastic like a hot knife through butter. notice the relay lens on the upper right has a sleek black connector at the end. that is the canon to nikon converter.

i'll try and post some video in the next 24 hours...

get to work!
-d

because the image will be upside down, to invert the image, all you have to do is flip the eyepiece to the opposite side of the camera. notice here...

http://www.dinoreyes.com/images/cam1.jpg

That looks like a significantly lengthy piece of equipment (your adaptor :p).

How's it like to operate with the focus ring all the way out at the front like that?

true, the unit put together starts taking on the appearance of a 16mm camera, so far handling the focus is not bad at all, you have to get used to the flipped eyepiece, but it starts making more sense because you can actually work the controls much better because you can finally see them all.

the real key is the "relay lens", that's where the added length in the piece is, the rest of the unit, from the front lens to the white plastic is probably as short as the other units for the standard dv cams.

my main goal was to make something very strong and if need be adjustable, notice the steel 52mm reversal ring (#1) i'm using to connect to the front part of the relay lens. i'll put the rails on for secondary support later, but i'm envisioning this to be my primary camera for shooting. i'll make another for a standard dv as a secondary camera as those are way cheaper and simpler to make once you have a nice lens collection.

-d

Could this work as a relay lens : Dallmeyer F1.5 15mm wide angle ‘C’ mount lens? Like Adam Bowman wrote earlier in this post "the mini35 relay lens is probably around 15mm <f2.0"! Or am I mistaken?

Thanks

I have posted in an an another thread this suggestion:
A macro lens, C mount for 16mm cameras. I think EdmundOptics have something in the relay lens section. The mount can be built in a camera body cap getting the right flange distance. A 16mm camera lens covers a bit more than 2/3" diagonal, so for the XL1 that has a 1/3 chip, will use only the central part - a very sweet spot.

There is such a vast amount of information out there on building some sort of home built mini35 system. I've read much of Agus and Aldu's posts, but they do not address the concerns for an xl1s. Im an owner of an xl1s with a 14x manual lense. I cannot focus on anything closer than 4 feet, and with anything but the widest setting, even farther. I understand the concept of the static ground glass setup, but I have no idea how I can acheive focus on the flange depth of a 35mm lens with my lense. Additionally, I've heard so many tings about fresnels, acromatic diopters etc... Are these all really necessary? What have other Xl1s users found? What sort of lense do I need to be able to focus with a longer focal length at less than 6 inches? its so hard to sift through all the posts out there on this topic, especially when much of the information does not apply to the xl1s. Would anyone be so kind as to give it to me in a condensed form? Im ready to put down the money for the materials to start expirementing, but Im not sure where to start.

Thanks,
Stephen

Stephen, not that this is necessarily the info you are looking for, but the 14x manual does have a macro feature, enabling close focus down to the front element.

Im familar with the macro setting, but, it is at widest setting, and you will see the entire ground glass rather than the projected image full frame.

Perhaps with some sort of telephoto in front of the lens, with the macro setting on it would be possible. I wouldnt know where to start without simply expirementing with different lenses, which I dont exactly have the opportunity to do.

Stephen

Gotcha. Thanks for the clarification.

<<<-- Originally posted by Stephen Birdsong : I wouldnt know where to start without simply expirementing with different lenses, which I dont exactly have the opportunity to do.

Stephen -->>>

You can adapt a cMount adaptor in to the camera body cap and attach a small macro lens for 16mm.
or get an adaptor for a 35mm Nikon macro lens from:
http://www.lesbosher.co.uk/XL1.asp
or
http://www.zgc.com/zgc.nsf/active/200471117190AB9E85256B81000CB326.
You will get a lot of distortion and unpleasant focusing problems with various diopters and third party attachments.
Even an enlarging lens with a M39 thread will give a better result than the myriad of attachments suggested. Also the size of a rig of your XL1 with standard lens and adaptors will put a Panavision camera to shame.

Ok, I've started on my first prototype, and wanted to post on it.

I found that Hollywood Frost works great as a substitute for ground glass. If your not familiar with it, hollywood frost, also known as opal, is a gel used in production.

What I did was take a somewhat sturdy box resembling a shoebox (it held a iron at one point).
I cut it in half, and rigged it so that one end went into the other so I essentally had a box that I could shorten or lengthen.

I then measured my flange distance (im using an olympus OMG 50mm lense) and placed a large cut-out of hollywood frost at the flange depth.

When I pointed the box at an object, I got a very crisp image projected onto the hollywood frost.

Now, I took my camera, and inserted the lens into the other end of my box, and drew focus. Obviously, Im not going to have a full frame at this point, because Im required to use the macro setting which is equivilant to a 35mm focal length (i think).

So, my problems are this: Im getting a serious hot spot, with major vignetting, and I need to be able to fill the frame with the image.

Im not sure if I understand the difference between a close up filter and a tele.

I do know that I need to be able to focus at less than 3 inches (which I can already do), and I need to be able to zoom to something like 600mm.

Any ideas?

Stephen
Ill try to post pictures of what Im talking about soon.

To: Valeriu Campan

I might have misunderstood your post but:

Are you suggesting that you could build a relay lens (like the one the mini35 uses) out of a lens-mount and a macro lens?

I'm danish and I'm having difficulties interpreting what exactly a camerabody cap is? Do you mean the plastic dustprotector you can put directly in front of the ccd chip - where you would normally mount the lens??

I think I'm getting more and more confused every day on how to get started on my adaptor!

Thanks

To Anders,
Yes, I meant to get a spare llens cap and adapt a cMount. Start with palstic, get the flange distant and upgrade to metal later

Ok - that sounds great! Do you know where or how I can get a hold of a c-mount adaptor for the XL-1?

About the macro - do you mean a complete 16mm macro lens or just a macro glass for 16 mm??

Thanks

Anders,
I don't know of any Cmount > xl1 adapters. My suggestion was to make one from a spare camera body cap and a metal adaptor you will incorporate in it. You can find some info about the flange distance of various mounts here:
http://www.gregssandbox.com/gtech/filmfacts/flange.htm.
Also I suggest to get a macro lens for, let's say Bolex, a Kilffit Macro lens. It is better to use a lens that is designed to work at close range in flat field environement. You can even consider an enlarging lens with M39 thread, but I will incline for lenses made to cover a small format closer to the 1/3 sensor of the XL1.

So here is an update on my progress.

I bought some pvc pipe, and found that 2" fits my 35mm lense like a glove. 58mm thread size will fit inside the pipe, and I used 2 uv filters to sandwich a piece of 216 (a different kind of diffusion, which seems to work a little better than hollywood frost)

So, I have a decent image in my ground glass, still a little vignetting happening, hopefully using real gg will solve that problem.

As far as the relay lens goes, this is what I've discovered:
even with +7 close up lens in any setup, whether wide, or tele, it is not enough to fill the frame. Having that much glass between the still lens, and my ccd is just stupid. So, I scratched the idea of trying to find something to put inbetween my lens and the gg.

And I tried something new. if you grab a still lense, and remove your lens from your camera, holding the still lens in front of the cdd, you can actually get a clear image. Problem is, its magnified so much, that its useless. I used a 50mm macro lens to no avail. I was able to get a full frame, but it was so telephoto it was worthless.

So, I grabbed a 16mm motion picture lens. This yeilded much better results. Still somewhat telephoto, but not nearly as much as 35mm.

So, my problem is, I need to figure out what 16mm lens I need. im not sure if I need a macro, because the lens I used seemed to already be functioning like a macro.

Any suggestions?
Anyone know where I can find any 16mm motion picture lenses?

Stephen

<<<-- Originally posted by Stephen Birdsong : Anyone know where I can find any 16mm motion picture lenses?

Stephen -->>>

Have a look on eBay. There are plenty. Also, EdmundOptics have a selection of close range lenses for 2/3 cameras.

Would an 8mm Bolex macro lens do? Or is it too small??

I don't know the size of the 8mm frame. If it is larger than 1/3 XL1 canon sensor, should be fine.

Actually wouldn't these lenses be perfect:

http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=1546&search=1

or

http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=1281&search=1

Which size would then work to our advantage?

Thanks

I have no idea. Only real way to find out would be to buy one.

My first incling is to say no. But on second thought, if it is that wide, then maybe you could stick it less than 1 inch from the GG.

That would rock, because the length of the total lense is something that we really need to keep down.

Working distance:
The distance between a subject and the lens surface.
Field of View
the size of the image that is visible. (not to be confused with the Angle of view, which is measured both in mm's and degrees. for example a 50mm focal length is an angle of view of 45 degrees)

Im definately in over my head, but Im trying to tread water.

Im guessing that we need a minimum working distance of under 1ft and i dont understand what field of view we need.

http://www.sweeting.org/mark/lenses/

if someone else can figure it out, go for it.

anders, i just wouldnt know which lense to buy.

Stephen

I would think that we need the widest lens, (the one with Angular FOV >43°)

But I have no idea nor the money to test several lenses!

You are right - we need help from somebody who really know optics!

Could somebody please help!!?

Thanks

One type of lens I saw used in capturing the groundglass for the video taps on 35mm movie cameras is a Cosmicar brand. Don't know the model number yet.
Also, this site will give a crash course in optics and how to calculate FOV and whatever...
http://www.1394imaging.com/resources/backgnd/optics/intro/?sid=1b47307c5ecea82c424b2e8d354d986f

anyone done anything new with their XL1 35mm adapters???