I'd like to build a mattebox and rail system. But I need some inspiration. Can anyone who has already done this post some images?

I have this idea in my mind of a wide matte box that has a bright white LED light on each side for use as eye lights.

This is one of the projects on my list. I've actually got two LED lights in mind, one of them being a simple rectangular one...kinda like the ones from www.litepanels.com.

The bright white LEDs are different than the other colors in that they must have a constant voltage and current supply. So you have to buy a circuit that will do this and they are called LED drivers. Otherwise you risk damaging or killing the LEDs.

I've gotten as far as getting the LEDs, but haven't bought a driver for them yet. I still need to decide how many I'm going to put in one light array. I plan on doing a few. I'll probably end up buying more LEDs and doing more light arrays. I bought 300 LEDs from a guy in Hong Kong off of Ebay. I just got them yesterday. Checked them out last night and they are sooo bright.

Court

Well that's good to know. Thanks for the info. I would have never thought the white LED's would be any different. Do you have any places you can recommend that can supply the LED's and drives for them? Besides ebay. Do you ned 1 driver per LED or will one driver power a lot of them? And also about how much power is needed for one of them?

Thanks

As for the rail system where can I get 15mm aluminum rod? Is it avaialbe at local hardware stores like a Home Depot or is it a more specialized type of thing? I'll check around today, just asking ahead of time so I don't have to make any unnecessary trips if not needed.

I wonder what exactly comprises these LED drives. I suspect it is not much more than a voltage regulator and a few capacitors. Anyone know?

I briefly searched around this morning for some. Here's a place that will ship out free samples - ON Semiconductor.

http://www.led-drivers.biz/products/nud4001.htm

There are others that will ship out free samples as well and most have sample circuit layouts that you can go off of to design your circuit for the number of LEDs you want to use.

You have to look at what the voltage and current spec is. You have to pick one that has a high enough current rating. The higher the rating, the more LEDs you can put on just one chip. This particular one is 500mA, which means you could power at the minimum 25 LEDs in series at once since 1 LED is rated at 20mA.

15mm rod should be very easy to find. I've already bought mine from a friend of a friend that was retiring from the machining business. To have something really nice you should use stainless steel thick-wall tubing. It doesn't really matter how thick it is, but you don't want something that's got a wall thickness of 0.010" either. I'd say anything over 0.070" is plenty thick. Obviously, the thicker the wall the heavier it'll be. I think my wall thicness was something like 0.100" It's just what the guy happen to have so I bought it. He charged me $1 a pound. It was about 4.5' long or so and cost like $3-4 bucks I think. Not a huge cost.

You should be able to find a metal scrap yard where you live. I seriously doubt that Home Depot is going to have stainless there. The only thing that they're going to have is aluminum conduit and brass tubing. Just look in the yellow pages for metal, metal supplier, something like that. And it should cost over $2-3 a pound for it. I hear the cost of aluminum has gone up and rivals stainless now.

Once you get your rod to length, you can do two things - tap one end to put a threaded stud in, or press fit the rod into an aluminum block (perhaps the base plate that's attached to your camera). If you press fit, 0.002" press fit is plenty big. 0.001" would probably do the trick just fine. 15mm is equal to 0.590" so the hole in the block should be 0.589" (0.001" press fit). You might have to machine down the diameter of the rod some depending on what you have find for a drill bit or end-mill bit to make the hole in the block.

I'd say at least 1.5" of rod length inside the block would be plenty. You'll have to put the aluminum in the oven and heat it up to about 375F and put the rod in the freezer. Leave them both in there for a couple hours. Remove from the oven and freezer and insert each rod immediately and quickly. Once it's in the block it will expand in size causing it to be stuck in there for good. If you have access to liquid nitrogen, that would be a better option.

For threading a stud in there, figure out what size tap you need to fit the diameter hole in your rod. You may have to enlarge the hole slightly with a drill bit. A certain tap has a certain drill bit to go with it. Get yourself some studs that are about 2"-3" in length and you're in business. Obviously, you'll have to tap both the rods on one end and the block.

Then, to make it look pretty and professional, machine up two aluminum plugs for the other end so that it's just slightly less in diameter than the rod (like about 0.002" under the diameter of the hole in the rod. You should be able to slide the plug into the rod easily. Then get the plugs anodized your favorite color and press fit them into the rod. The anodizing process will add at least 0.001" to the radius of the rod, meaning at least 0.002" in diameter. You'll have yourself a slightly eye catching, very professional looking rod system.

On the other hand, you could also skip the press fit process and machine the plugs so that after anodizing it's the same diameter as the hole in the rod and just glue it into place.

Court

I wonder what exactly comprises these LED drives. I suspect it is not much more than a voltage regulator and a few capacitors. Anyone know?


You pretty much hit it on the head. The white LEDs are more acceptable to damage if the voltage and current isn't regulated. At the least you'll shorten the life of your LEDs if you don't use a driver. A driver will ensure that you get all 100,000 hours of use out of your LEDs.

Court

For DIY, does anyone know where to find specifications or drawings for 35mm rail systems?

-how long are the rods? how far apart? distance from the center-line of lens?

Lenght is subject to brand of MB, FF, lens you want to use, etc. Could start with 150mm and up. Standard distance for 16mm cameras (and video) is 60mm apart. Distance to optical axes is 80-85mm (again, depends on MB)

Looking around on Ebay, I found some 15mm rods at 8" long if anyone is interested in buying them rather than making them.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4690&item=7521617791&rd=1

Court

I've built an led light and this is the driver I recommend- fatman at this site http://www.taskled.com/fatman.html. You put 4 leds in series to make say 3.5v x 4 = 14v. (You make the strings of 4 equal to one another by matching the leds) Using the fatman you can get up to 1amp! and your power source can be 6 to 12v. Also can be ordered with a dimmer pre mounted. Its around $25. Gentlemans name is George and hes very nice.

Nice to see this interest in the project is growing. I made a 198 LED on camera light. Basically its the same as the LitePanel but brighter and tungsten balanced. First thought was to do it daylight balanced too but I realised that outdoors these led panels arent bright enough and I didnt want to cut down my light with a CTO when I used it in doors so I felt tungsten LEDs were the way to go. If your considering a dimmer for your light you'll have to use a pulse width mod. with a high frequency. Also consider the battery source you want to use early on because it determines your LED layout. I went with Panasonic DVX batteries (one of a few ideas that is now being used on the LitePanels). The reason why I went thru all of this trouble is I wanted to unleash myself from thoughs big/heavy batteries that are normally needed to run a light. Having the light with the batteries docking on the back made for a tiny, light weight package that was steadicam friendly. Its a fun project that I still add to these days. In fact some of the mods I'm working on next are so uniquely cool and useful that I'm currently looking for investors to turn it into commercial product. I'll let you guys know if something comes of it.

hello Brett,

would you liek to share some of your thoughts how you have done the LED project? i would just like to DIY an LED light similar to lite panels but not condiering to make some profit out of it. just want to save some cash for some other video stuff. btw i'm from philippines that's why buying lite panel is too expensive for me just starting out...

I have actually done some projects, but for this one i have just put it in a breadboard where I series 3 LED supplied by 12v regulated supply. eventually i can put some more LED...in parallel...i got confused with that...what i'm trying to say is i have some 5 sets of 3 LED(in serries) to be connected in parallel. hope to have some of your thoughts. thanks

The attraction in building a bars support is to use a matte box and follow focus? Right? ... two items that are outside the price range of anyone looking to build the support. The funny thing is the bars have to be custom fit for specific cameras, yet they also must accept standardized matte boxes and focus pullers! It's very difficult to know the correct dimensions without having one in front of you... And, if you have one in front of you, then you're not really inclined to build one! Hence, this is a difficult DIY project. Kind of along the lines of building your own fluid head. Buying one will actually look like a deal comparison. Cheers.

well personally it doesnt seem like it would be that difficult to come up with a DIY followfocus and mattebox. What would be great would be if someone (perhaps with their own rail system and mattebox already or with a knowledge of the necessary dimensions) posted some info about how to make your own. There might be enough information on these boards to come up with a design without detailed plans, but it would be amazing if some details plans with pictures turned up about building rails, mattebox, and followfocus on the same level of some of the diy plans available online for GG/wax adapters. I know I'd really like something like that. Rails and mattebox seem if anything even simpler than 35mm adapters, but its not obvious the dimensions or the best mounting mechanism or the best materials to make a mattebox that looks reasonably professional. Seems like all these things including followfocus would be quite possible to build somewhat easily from homedepot parts just no one who has tried has documented thoroughly.

two items that are outside the price range of anyone looking to build the support Not for long and not just "another" ff. Sorry but I will refrain to list the features till is avail. Would $300 be to much (again) for this ff? (least expensive I found was $750) Worth YOUR TIME to diy? The prototype is finished (last pic on the page)
http://dandiaconu.com/gallery/album04
and I have the parts in the making. It will be a home assembly kit. (three screws....some kit)

Rails and matte box seem if anything even simpler than 35mm adapters, but its not obvious the dimensions or the best mounting mechanism or the best materials to make a matte box that looks reasonably professional. Seems like all these things including follow focus would be quite possible to build somewhat easily from home depot parts just no one who has tried has documented thoroughly Rods 15mm, AL, steel or carbon fiber, 12" to 16" long, 60mm apart (center to center). There is no "best mounting mechanism". There are only options to suit specific needs. .... inexpensive and good are hardly a match. Some will have more than two filter trays, some will allow rotation of one filter, and lately some are made to allow for 16:9. What do you NEED and how much you can AFFORD is part of the same equation. There are things that CAN and CANNOT be done using of the shelf stuff. The mainstream of mass production has not reached yet this narrow market of film/video gear. I do not think it will. Is too small, is changing to fast and the money to be made are based on a "luxury" not "NEED". Ex: can you shoot wo a MB? yes you can. Can you shoot wo a CAMERA? no. This is (imo) the diff between NEED and Luxury (for many) Obviously, for some a MB IS A NEED!! (but their revenue allows and cries for it)
This is why I do not see it a mass production item. Here:
http://www.cavision.com/main.html
but if the quality is not good enough or if you find they do not work as good as expected, do not get back to me. I do not work for nor endorse Cavision products (my 2c on the issue)