How to Build a Ring Light *Edited*

Posted: Fri Nov 25, 2005 1:18 pm

Found this site on how to make your own ring flash pretty neat.
Ring Light *Edited*

Posted: Sat Nov 26, 2005 8:51 pm

adorski wrote:

Found this site on how to make your own ring flash pretty neat.
Ring Flash

Should be: how to build a ring LIGHT. This is a continuous light, not a flash.

You can also mount four (4) 24" fluorescent light fixtures into a square and cut a hole to shoot through. This will put less strain on your electric service and will yield a daylight result if you use high end fluorescent tubes (CRI 92 or higher). No heat either.

Posted: Sat Nov 26, 2005 11:04 pm

Actually, according to Naturallighting.com, a CRI 92 bulb is "not recommended for critical color areas" - they recommend a so-called vita-lite instead. So I googled that but didn't find any real specifics, just a crummy bar-graph spectrum, I can't tell to what extent the mercury lines are there.

The emission spectrum of a mercury-containing fluorescent lamp, no matter how much you try to correct it, is quite spikey, not at all like daylight. People cite colour temperature alone, or they cite CRI, but what do these tell you when you have a smooth background with a bunch of sharp peaks sprinkled throughout the spectrum? They just fit the smooth background and produced a number, that's all.

In the case of most fluorescents, the most prominent peaks are from mercury. As far as I know, every common fluorescent light contains mercury, and that's primarily where the spikey emission lines come from. I think there are some xenon fluorescents too, but the Xe spectrum is pretty spikey too and the bulbs are less efficient.

So again I say, just say no to fluorescents for photography!

Actually it's about time to say no to anything containing mercury which routinely winds up in the dust bin.

:) keithwms

P.S. There is a company called solux which claims to have a much better spectrum than its fluorescent competitors, but I can't say first-hand whether it's because of a lack of mercury in the tubes or what. The company claims that the tubes are widely used in art houses, I can't verify that, and I haven't measured the spectrum myself.

Posted: Sat Nov 26, 2005 11:40 pm

Mercury? Weird. Given how satisfying it is to smash those things, you'd think there'd be a warning on the carton.

Posted: Sun Nov 27, 2005 12:00 am

packard wrote:

adorski wrote:

Found this site on how to make your own ring flash pretty neat.
Ring Flash

Should be: how to build a ring LIGHT. This is a continuous light, not a flash.

You can also mount four (4) 24" fluorescent light fixtures into a square and cut a hole to shoot through. This will put less strain on your electric service and will yield a daylight result if you use high end fluorescent tubes (CRI 92 or higher). No heat either.

LOL ROTFLMAO thank you Teacher for correcting me, whew! too much excited to share the link I found never check my link is about continuous light not flash. sorry again my bad,
Okay title will be edited.

Posted: Sun Nov 27, 2005 10:29 am

walter23 wrote:

Mercury? Weird. Given how satisfying it is to smash those things, you'd think there'd be a warning on the carton.

LOL You should never smash a fluorescent! Have you ever heard the term, mad as a hatter?

This site http://www.mass.gov/dep/toxics/stypes/flampbiz.htm even recommends leaving the room for a time if you do break a fluorescent lamp! At any rate, all spent lamps should be given, intact, to a recycler, not put in the trash.

:) keithwms