You guys know that kinos and other pro flo's don't use stock ballasts (like the video about screwing shop lights to wooden strips shows), right? The ballasts are overdriving the bulbs to get higher refresh rates (no flicker) and higher output.
A DIY "Kino" should be overdriving - most DIY projects are just "bolt some shop lights together".
Results 11 to 20 of 20
08-07-2012 02:10 PM
08-07-2012 02:51 PM
All off the shelf fluorescent ballasts underdrive bulbs just a bit. This is because in commercial lighting, they most care about life of bulb, not so much output. In film / tv lighting we care about the opposite. More output, life not quite as important. The issue of the frequency of output is another one too. For some reason many stock ballasts never list the output frequency, even if its a good one. Not sure why, maybe most buyers aren't sophisticated enough to understand the spec. That determines whether they flicker or not in front of your camera.
I am sure Kino Flo does overdriving of output (and driving frequency must be high as well) and we do it to a lesser extent on output (I don't go quite as far as they do and our ballasts drive at 40K to 50K hz frequency) but you'll never find an off the shelf commercial ballast which does overdriving of output. You'll have to figure out ways to do it for yourself in DIY if you want it.
08-26-2012 12:41 PM
- Join Date
- Aug 2011
Just to add to the thread, I found this link http://ctkfilm.com/resources/diy-kino-flo/
08-26-2012 11:23 PM
PS - The ballasts that I got are Energypro TKT8's. They're only meant for normal lamps, not high output ones like you'd find in a 4 bank fixture, but they work great for how cheap they are. They don't flicker.
- Join Date
- Aug 2011
09-02-2012 03:50 PM
Wanted to share how I built my kinos. Started with a flat piece of .040 thick white aluminum. The thinner
the aluminum, the lighter your light will be. If you can find it, there is an .032 thickness. I Rounded the corners
for safety, and put a 1/2" 90 degree bend on the 2 sides that run parallel to the bulbs for stoutness. You will mount
the bulb fixtures to this piece. For the barndoors I used 4mm black coroplast. This can be found at sign supply or
plastic supply shops. The coroplast piece runs behind the aluminum and the two pieces will be attached to each
other with some actual Kino parts. You will need the following...(these are for a 4bank with 2' long bulbs) wire
channel repair kit prt-fix-4s, fixture Silver conduit prt-fh4, and fixture wire repair kit exp-for-s. These are available
at B&H Photo. All this may seem foreign, but if you do a little research on kino's & B&H's websites, you will see how
the parts work. I cut holes and ran the wiring out the back, wired with xlr connectors so I could have remote ballasts.
I built these many years ago, so they are set up for the t12 size bulb, but the shell should work with most fixtures.
I use the Fulham workhorse 7 ballast to run two lamps, based on the recommendation of Fulham. Color balance is
perfect & output is very close to Kino specs. Not flicker free at all speeds, but tested & flicker free at 1/24. 1/48.
1/60. & 1/120
Last edited by bruce southerland; 09-02-2012 at 03:59 PM.
09-02-2012 06:20 PM
- Join Date
- Aug 2011
Thanks so much for posting this? Seems like they don't flicker at 1/24 which is what most filmmakers would be concerned about right? May I ask what the total cost ended up being? Possibly a picture of them in action? Just wondering how much light it throws off.
09-02-2012 07:17 PM
Sorry, it's been too long ago to remember the cost per unit. As far as output, the Kino data specs says their 2' 4 bank puts out 29 foot candles @ 6' and this DIY unit puts out the same (using the Kino bulbs).
09-04-2012 08:41 AM
Nice Work and Thanks for posting this Bruce!
03-30-2013 02:06 PM
So, it's been a while, but I did not forget about this project, in fact I built the bulk of it back in September. However, I didn't get around to fully finishing it until now, here it is:
The gel frame is just 3/4x oak with some right angle brackets. The egg crate was purchased from Canal Plastics, one of the few places on Canal street that still offers useful products and not ripoff Louis Vuitton bags. It's actually two pieces doubled up, the parabolic reflector does enough of a job at directing the light that one piece of egg crate at only 3/8" thick wouldn't have done too much.
Above is without the egg crate, showing the reflectors. It's mirror finished aluminum purchased from eBay, the name of the eBay store escapes me but the company is called Online Metal Supply. This is the exact product - http://www.onlinemetalsupply.com/alu...finish-94.html
The reflector may look a bit crude, but notice how much the tubes fill the reflector above as opposed to below, which was taken from off-axis.
Above is from when it was under construction. Each of those pieces had to be cut on a scroll saw to a near perfect parabola. If you have access to a machine that can bend sheet metal to the right shape it wouldn't be necessary to do this many of them. You don't need to screw the metal into all of them either, just doing half of them is more than enough. But when the metal starts out flat, you need the skeleton to keep it bent in the right shape.
This is the shape of the light that it puts out. You can see that it's a pretty focused beam of moderately soft light. The egg crate would just reduce the spill coming out of the sides.
Next time I actually use it to light a person I'll post what it looks like.
After building this, I can say with fair certainty that I won't be making one like this ever again. I'm considering building some that only use a single tube, but this one is so heavy that I'd much rather it be in a medium roller than a C stand, and there's no way I would use it vertically. The mounting pin is already slightly bent from testing that out.