Pics of New Two Strip Camera 1

[Brian Rose]

All,

Well, over winter break, after a lot of research, and some help from more than a few forum members, I built my first prototype camera system for the multistrip color effects that I have been experimenting with. This system is relatively simple, relying upon a beamsplitter, and two 16mm cameras mounted at precise 90 degree angles, and calibrated to run at the same frame rate. I can now record two geometrically identical images, thus elimintating the problems I had before with fringing and motion. And, since the whole system is contained in one space, on a single tripod, I can do pans, tilts, and almost any other camera movement (zooms are, unfortunately, not possible at this juncture). I will begin some camera tests and hope to have the footage back soon. For the meantime, I am only able to shoot two strip color (red and green), but I hope to eventually make a three strip system. Once I have the new footage in, I will post frames. Until then, here are some pics of what I've built so far. Again, just a prototype, but I'm looking forward to what it may yield. Thanks again for all your help in making this possible!

 

 

 

 

 

 

Best,

Brian Rose

PS: Congrats to David Mullen on his latest achievement. I can only dream of someday making such beauty!

[Richardson Leao]

dude, fantastic set-up! the beam splitter, it passes all wave lengths?

[Brian Rose]

It can convey the range of visible light. Then, I use wratten filters mounted behind each camera lens to capture the range of the spectrum I require.

Best,

Brian Rose

[David Mullen ASC]

It looks interesting, but how are you going to add that third camera someday for 3-color?

[Brian Rose]

"It looks interesting, but how are you going to add that third camera someday for 3-color?"

 

Very good question. This first camera system is basically a dry run for the more complex three strip system. It carries the same principles involved with the three strip camera I am planning, but it is simpler. I figure, better to encounter problems and setbacks on this more basic system, before I invest too much time and money in the bigger three strip model. But, to answer your question, yes I will have to redesign it somewhat to add the third camera. Basically, I will have to add an additional beamsplitter for the third camera, which means I will have to also to some recalculation, since such a change creates some new problems in the optics. Below is one design I am proposing. It is very similar to the current two strip system, except that the rear camera is set back further, and a second beamsplitter put in its place to make room for the third camera. However, by setting back the one camera, I will have to readjust all three, so they are equidistant, and therefore capture the same image area. And, I am sure there will be other complications, but hopefully I can work through as many as possible with this first set up.

 

 

Best,

Brian R

[Jonathan Bowerbank]

Looks like a lot of fun :)

 

Can't wait to see some results

[Mitch Gross]

That's pretty sweet, Brian. When the time comes for the three-strip version, I suggest trying a prism like the old Techincolor cameras used rather than a pair of beamsplitters. It should be much cleaner a system.

[Leo Anthony Vale]

---With slight modification, it can also be used as a stereo rig.

[Brian Rose]

Thanks for the suggestion Mitch. I had researched Technicolor's camera system a lot, and believe it or not, their system was pretty similar to mine. They used a single, cubic beamsplitter to get two separate images. The difference was, they used a bipack, with two strips of neg sandwiched emulsion to emulsion. I attached a rough drawing of how their camera worked.

 

 

Best,

Brian R.

[Matthew Buick]

Wow, you amaze me! :D

[chuck colburn]

All,

Well, over winter break, after a lot of research, and some help from more than a few forum members, I built my first prototype camera system for the multistrip color effects that I have been experimenting with. This system is relatively simple, relying upon a beamsplitter, and two 16mm cameras mounted at precise 90 degree angles, and calibrated to run at the same frame rate. I can now record two geometrically identical images, thus elimintating the problems I had before with fringing and motion. And, since the whole system is contained in one space, on a single tripod, I can do pans, tilts, and almost any other camera movement (zooms are, unfortunately, not possible at this juncture). I will begin some camera tests and hope to have the footage back soon. For the meantime, I am only able to shoot two strip color (red and green), but I hope to eventually make a three strip system. Once I have the new footage in, I will post frames. Until then, here are some pics of what I've built so far. Again, just a prototype, but I'm looking forward to what it may yield. Thanks again for all your help in making this possible!

 

 

 

 

 

 

Best,

Brian Rose

PS: Congrats to David Mullen on his latest achievement. I can only dream of someday making such beauty!

 

Hello Brian,

 

Just a suggestion on your beam splitter. I see your using plate glass which has a couple of disadvantags for this application. First it is not very flat and second it has an intrinsic coloration (see green coloration when looking at the edge) inherent in the formula of the pour. A better choice would be a water white float glass (that's a glass thats poured on a bed of liquid tin) it's much closer to being optically flat (without being ground and polished) and does not add coloration to the image. Also try and keep the thickness as thin as possible.

 

Chuck

[Brian Rose]

Chuck,

Thanks for the tip. You're right about the glass. It does have some flaws, but it came reasonably cheap. Once I get my test shots back, I'll have a better idea of what changes I will need to make. If all goes as I hope, I plan to upgrade the optics, per your suggestion. Thanks!

Best,

Brian R

[Jon Kukla]

Clairmont already have a system that can do this - it was used on Crazy Horse about ten years ago essentially as a cost-effective motion control system so that they could shoot the same scene simultaneously on b/w infrared stock and color negative, and then use CGI to make the humans b/w while keeping the landscapes color.

 

The major problem, apparently, was that it wasn't enough for the lenses to be of the same focal length from the same company - they needed to actually be from the same glass die due to the minor imperfections which may make a given 50 mm lens actually 49.8 mm or 50.1 mm in fact.

 

It takes a lot of testing to actually make your lenses match field of view precisely, so keep an eye out for that. But otherwise, good luck! Look forward to seeing your results.

[chuck colburn]

Clairmont already have a system that can do this - it was used on Crazy Horse about ten years ago essentially as a cost-effective motion control system so that they could shoot the same scene simultaneously on b/w infrared stock and color negative, and then use CGI to make the humans b/w while keeping the landscapes color.

 

The major problem, apparently, was that it wasn't enough for the lenses to be of the same focal length from the same company - they needed to actually be from the same glass die due to the minor imperfections which may make a given 50 mm lens actually 49.8 mm or 50.1 mm in fact.

 

It takes a lot of testing to actually make your lenses match field of view precisely, so keep an eye out for that. But otherwise, good luck! Look forward to seeing your results.

 

Hi Jon,

 

What is a glass die?

 

Chuck

[nathan snyder]

Good job Brian. Looks like you got it figured out. Man, I am impressed. Do you have a website with this info I can link too from my website?

[Brian Rose]

Unfortunately no. I'm pretty behind the times when it comes to webpages. Ironic, huh! I do have an album at photobucket, where I keep my latest images. Hopefully I'll upgrade, but until then, I hope this will be satisfactory. Thanks for taking such interest in my work!

 

http://s127.photobucket.com/albums/p140/Brianruns10/

 

Best,

Brian Rose

[Bernhard Zitz]

Hello Brian,

 

great idea, I was already pretty impressed by the tests you posted a while ago. Back then I've been thinking about a three-strip system similar to yours but with only one lens in front of the prisme. The problem then would be that lens is to far away from the filmplane, there's the bulky prism between, you would end up with a system that only does macro due to the distance of the lens.

 

if you put a minus diopter (like certain wide-angle-adapters, for example the Schneider UWL) in front of your singlelens-system you should be able to compensate this marco effect... -9.5 dioptries should be enough...

 

 

If you take the threestrip-system you posted and you don't put a lens on each camera, but only one lens in front of the prism, then make sure every camera has exactly the same distance to this lens, then put a minus diopter on your lens to compensate the macro-effect...

 

 

This is only a thought from an amateur, no idea if this really could work...

 

cheers, Bernhard

[Chris Keth]

Chuck:

 

When they make blanks for lens elements, they have to make relatively small lots of glass compared to what they will need total. It's a very, very precise process that makes it nearly impossible to get precisely the same chemical content in each batch of glass twice. The chemical content will determine the optical performance of the glass and two lenses of the exact same design can be made ever so slightly different if glass from different pourings is used.

 

Usually this doesn't matter because who would even notice a .1mm descrepency from lens to lens but in this application, it does matter. One lens could have a slightly higher reproduction factor, or smaller, or slightly out of spherical, etc.

[David Mullen ASC]

great idea, I was already pretty impressed by the tests you posted a while ago. Back then I've been thinking about a three-strip system similar to yours but with only one lens in front of the prisme. The problem then would be that lens is to far away from the filmplane, there's the bulky prism between, you would end up with a system that only does macro due to the distance of the lens.

 

Now you know why a 35mm was around the shortest focal length used in 3-strip Technicolor photography, unless they used a wide-angle adaptor on the front of the lens.

 

The trick would be to make a prism that wasn't much bigger than a modern spinning mirror shutter. But then you'd also be talking about a camera that wasn't a spinning mirror reflex.

[Hal Smith]

The trick would be to make a prism that wasn't much bigger than a modern spinning mirror shutter. But then you'd also be talking about a camera that wasn't a spinning mirror reflex.

Anyone ever try using a modified spinning mirror camera with filters between the mirror segments? With a three segment mirror/filter you could shoot three color at 72fps (for 24fps) and sort the colors out with modern scanners, etc. You could even use an optical step printer to get separation negatives. There would be some back focus issues running filters behind the lens but nothing like running your image through a prism.

[David Mullen ASC]

Early color processes tried something like that, but the problem is that each color is still captured sequentially, not simultaneously, so there is color fringing when anything moves.

[Hal Smith]

Early color processes tried something like that, but the problem is that each color is still captured sequentially, not simultaneously, so there is color fringing when anything moves.

Aha! Thanks David

[Leo Anthony Vale]

Now you know why a 35mm was around the shortest focal length used in 3-strip Technicolor photography, unless they used a wide-angle adaptor on the front of the lens.

 

The Technicolor Three-strip camera did have a 25mm. It was made by Cooke & was one of the first inverse telephoto (retrofocus) designs.

 

a later British three-strip camera, maybe made by dufay-Chromex, probably had nothing shorter than a 35mm, perhaps Dallmeyer.

[Kenny N Suleimanagich]

is there any f-stop compensation you need to do? it seems like you'd be compensationg a full stop after the bolex's beam splitter AND the one you have built, maybe even more.

[David Mullen ASC]

it seems like you'd be compensationg a full stop after the bolex's beam splitter AND the one you have built, maybe even more.

 

Plus the red or green filter, which has to be fairly dense.

 

Now you know why the 3-strip Technicolor process was a number of stops slower than the b&w stocks of the day.