Bertil Holmberg wrote:
Does anyone have experience of LED lighting panels in photography?
Although there are commercial products available, it should not be
that difficult for the electronics buff to make a couple of panels
quite cheap. White high intensity LEDs are avaialble for about $50
per 100 and that should be enough for small object photography, I
think. With 25-50 light sources mounted close together, a diffusor
seems unnecessary.
Ah, the Wiki says
that a 100W bulb emits about 120 Cd. A 5mm LED can give 20.000 mCd so
100 of the blighters should give 2000 Cd. That sounds pretty intense,
does't it?
These figures mean little without defining angle/shape/distribution of
the light beam from both sources.
More info on LED light output measurement:
http://www.marktechopto.com/engineering/measurement.cfm
Generally speaking, you should not expect any savings as compared to
tungsten - in power required and especially not in cost of devices.
There are some white LED lamps available for macrophotography - their
advantage over tungsten or flash may be reduced weight and size.
A white LED used as light source for photography is not (yet) a good
idea, especially if decent colour reproduction is required and film is
used rather than RAW power of digital :)
Spectrum of white LED is continuous (contrary to some "urban legends") -
but distribution within the visible spectrum is different than tungsten
or daylight colour films expect.
Another problem is quite big variation of (perceived)colour, even within
one production lot.
More on this:
http://www.maxim-ic.com/appnotes.cfm/appnote_number/3070
cheers,
teem
