Hi C.H., Moose, Ken, Fernando and all,
From: "C.H.Ling" <ch_photo@xxxxxxxxxxxxx>
>Really? But most if not all the professional light boxes are using
>fluorescent lamps. More interesting is I just found there are many
>fluorescent studio lighting system on the market.
However, one thing is lighting a studio scene, and another is to put light
of a suitable spectrum thru the dyes of a slide... metamerism _is_ an issue
with the latter. Again, the demise of slides in the pro market makes
"accurate" light tables much less needed.
From: Moose <olymoose@xxxxxxxxx>
>Like Ali with high end DSLR low light capability, I suspect Carlos isn't
>up to date on lighting developments.
Most likely. However, I can speak only for what I can purchase over here...
See my comment to C.H.'s post.
I have to admit that I'm biased against fluorescent lighting, especially
CFLs -- and now the EU is banning incandescent bulbs! Everything started
early this summer, when my first Provia-400X scans came out with an _awful_
red/magenta cast:
<http://cjss.sytes.net/post/scan/provia400x/Untitled-8.jpg> (as came out
from the scanner, just scaled down)
The slide doesn't look like that... but when seen thru CFL light (my bulb is
IKEA brand, definitely not State of the Art) it does! Maybe my CanoScan
9950F is dying... but metamerism is a real concern, at least with some
emulsions. The very same scanner does much better with Astia-100F:
<http://cjss.sytes.net/post/scan/astia100f/velefique.jpg> which does with a
much more reasonable correction.
And... my new Panny GF-1 does a very fine work at AWB, much better than the
300D. But the only lightsource which deceives it is the CFL -- fortunately,
it's very easy to use the manual WB option ;^)
From: Ken Norton <ken@xxxxxxxxxxx>
>Every television studio I've been in in the last dozen years has been
nearly
>100% florescent for primary lighting.
Ditto. Actors don't look at slides :-)
From: Andrew Fildes <afildes@xxxxxxxxxxxxx>
>>100% florescent for primary lighting.
>
>...or perhaps the flowers? ;-)
LOL!
And then from another thread...
From: Moose <olymoose@xxxxxxxxx>
Subject: Re: [OM] 80/4.0 Macro resolving power?
>Fernando Gonzalez Gentile wrote:
>> Mmm !!
>> Was the 5D color balance set to fluorescent, daylight, auto .... ?
>>
>
>The light source is supposed to be daylight WB, so that's where I set
>the camera.
So you were "copying" the slides with the rig pointed to natural sunlight,
weren't you?
>The question you haven't asked is what color is the slide really?
>Projected, it's one color, viewed against a light window another, viewed
>on the light table, yet another.
A very, very, very good point! Slides are intended to be seen thru a
black-body illuminant of 5000ºK -- the exact temperature is not critical as
long as it has a continuous spectrum of the black-body class, the human eye
is surprisingly good at this.
So, the most accurate way to illuminate the slides is direct sunlight,
reflected/diffused on a neutral surface. If you're pointing at the blue sky,
the balance may be way off.
Unless you're comparing with a monitor, second best is projected: the
halogen bulb is warmer (circa 3200ºK) but being black-body the eye
compensates easily for this.
I have tried to use my monitor (LG 1910S, IPS type panel set @ 6500ºK) as
light source and, while better than my CFL, it's still very poor. OTOH, a
"white" LED flashlight is surprisingly good at this, at least compared with
the fluorescents.
Cheers,
--
Carlos J. Santisteban Salinas
IES Turaniana (Roquetas de Mar, Almeria)
<http://cjss.sytes.net/>
--
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