Newbie question about flourecents

[Alex Filacchione]

I see the Kino flows, etc. and they are incredibly expensive for my budget.

I looked at the lighting fixtures at www.ahsupply.com and they look very interesting. They are basically for aquariums, but they are compact and lightweight (as opposed to the fixtures/ballasts that you see at a Home Depot - smallest seems to be 4 feet long).

The question is, could I get one of these AHsupply setups and get the daylight (5600k) flourescent light bulbs that you see at Home Depot these days and have roughly the same kind of setup?

I understand that the Kinos have a dimmable ballast. I understand that they put out a lot more. [edit: I mean that they put out more LIGHT :-Þ ]

One of the things that I am really wondering about is flicker, etc. I don't know much about flo lighting. Do they flicker just when they start getting worn, or is the flicker dependant on a crappy vs superior (read expensive) ballast?

Thanks,

Alex F

[Rob Lohman]

Anyone?

[Carlos E. Martinez]

I will try to tell you what I could find out on alternative budget lighting, as that is a matter I am also very much interested in.

To start with all those new modern fluo fixtures, like Kino, are based on high frequency ballasts. So you won't have any flickering, even if used on different frequency countries.

Then comes the matter of color spectrum, which apparently is determined by the lamp's CRI. The higher that CRI number, the more linear it is and the closer it will be to a similar incandescent or daylight type. That CRI number seems to be related to the non-linearities standard fluo tubes seem to have and the different phosphor the tube is covered with.

Then comes the light temp, which is closer to 3200 K or 6000K, for incandescent or daylight equivalents. The former are more yellow and the latter more bluish. Be careful if you mix them.

IMHO you should forget about using dimmers for a low-budget light of this type, as they have to be electronic and won't be easy to solve. Standard dimmers do not work, as they are designed for incandescent bulbs. Fluo dimmers work changing the frequency, as far as I know. Instead try to find ND gels if you need to control light intensity or get simple wire mesh, as it's traditionally used on light heads to lower the light output.

Those AHsupply kits look quite interesting, and you can use bulbs from other sources, as long as the base is right. They claim you can only use their bulbs, but that's commercial BS.

There's also a cheap light head you can find at Home Depot, called Fluorex Worklight that might be a good choice too, if you use some silk up front to soften the lighting. You will also need some way to control spill, but that's also valid for all fluo types.

It might be a good idea to take your video camera to the shop and see what the light looks like when hitting a face. Taking a colour card might be a good idea too. Don't forget to WB for that light.


Carlos

[Alex Filacchione]

Thanks for the input. Couldn't find the Fluorex at HomeDepot, but found them online. They seem to run in the $35-40 range. Bulbs are about $8.50 for them and supposedly run at 6000k light temp.

For around the same price I am thinking that the AHsupply might be better just because of the reflector, even though it means more work as far as making a box for it. The good thing is that if I make a box I can also attach pieces to the box for hanging, mounting, etc.

I might just get 1 of each. :-)

I see that most of the flo bulbs (T8 & T12 sizes at least) have 2 different daylight bulbs. There are the 6000k daylight and the 5600k daylight. The Kinos run at 5600k, IIRC.

Would a 6000k just be too blue? My guess is that with WB and gels, etc. in the long run it shouldn't make a lot of diff, just as long as they are daylight and not the normal green flo bulbs.

Is the CRI # a number that rates the bulbs themselves, or the fixture/ballast? From your description I am thinking the bulbs. Is the CRI number the "daylight 97" number that I am seeing on the bulbs? I think that the 5600k lights were somewhere around the high80's and the 6000k were in the high 90's, but I thought that that number was something like "97% like daylight" or something like that. In that case would I be better off getting 97 bulbs?

Thanks for your help!

Alex F

[Kyle Ringin]

The CRI# is a property of the tube, not the fixture.

The three (main) problems with cheap flouro lighting for video are:
Some fixtures flicker
Some fixtures hum
Some tubes do not give a good colour response.

I bought a 2x4' bare flouro fixture (with standard inductive ballasts) from the hardware store and it came with Tri-phosphor tubes (cool white). It flickers a bit until it warms up, then it is fine.

You can only hear the hum when you put your ear to it.

The Tri-phosphor tubes work quite well with my camera, but they aren't very useful because they are cool white.
I was doing some shooting in the country and wanted warm white to match other lights but the only store that had tubes only had cheap $3 warm whites. I used those and a warm white compact flourescent and the results were fine - no flicker, no colour problems. That said I would recommend tubes with a high CRI# when available.

Cheers