I'd like to create a panel of LED lighting to mimic (white) sunlight for indor photography... (LEDs for efficiency and lower heat output). Are white LEDs a little too blue? Should I try some ratio of red, green, and blue LEDs (like 3:7:1)? Has anyone done this before?
want to mimic sunlight w/o heat for indoor photos
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Re: want to mimic sunlight w/o heat for indoor pho
hmm...I don't want to blind my subjects.... "Blue light, by the way, is damaging to the retina, in the same way as are other shorter wavelengths (e.g. ultraviolet). Cumulative exposure is a principal cause of decreased contrast and sensitivity (nightblindness) in elderly people. Ditto for cataracts, which are in large part a result of damage done to the eyes' crystalline lens by short wave light." -- Jamaica (http://www.candlepowerforums.com/ub...er=1021152&page=&view=&sb=5&o=&fpart=all&vc=1)
hmm...I don't want to blind my subjects.... "Blue light, by the way, is damaging to the retina, in the same way as are other shorter wavelengths (e.g. ultraviolet). Cumulative exposure is a principal cause of decreased contrast and sensitivity (nightblindness) in elderly people. Ditto for cataracts, which are in large part a result of damage done to the eyes' crystalline lens by short wave light." -- Jamaica (http://www.candlepowerforums.com/ub...er=1021152&page=&view=&sb=5&o=&fpart=all&vc=1)
[ QUOTE ]
achoo said:
Should I try some ratio of red, green, and blue LEDs (like 3:7:1)? Has anyone done this before?
[/ QUOTE ]
Of course. It's a big world, somebody's sure to have done just about everying.....
In this case, try Don's excellent RGB page . He'll tell you how many of which color you need to get what color temperature.
The rest of his stuff is well worth the read as well, but that wasn't the question......
Doug Owen
achoo said:
Should I try some ratio of red, green, and blue LEDs (like 3:7:1)? Has anyone done this before?
[/ QUOTE ]
Of course. It's a big world, somebody's sure to have done just about everying.....
In this case, try Don's excellent RGB page . He'll tell you how many of which color you need to get what color temperature.
The rest of his stuff is well worth the read as well, but that wasn't the question......
Doug Owen
Re: want to mimic sunlight w/o heat for indoor pho
If cost isn't an issue LEDs would be nice but would take some doing. You would have to use 3watt white LEDs and possibly sprinkle a few blue, green, and red ones to adjust tint to suit your needs.
If cost and time is an issue then go with the fluoros.
If cost isn't an issue LEDs would be nice but would take some doing. You would have to use 3watt white LEDs and possibly sprinkle a few blue, green, and red ones to adjust tint to suit your needs.
If cost and time is an issue then go with the fluoros.
KevinL
Flashlight Enthusiast
Re: want to mimic sunlight w/o heat for indoor pho
White LEDs are fine - at least in my application. I've used a Surefire L4 and U2 as illumination for closeup photos of equipment and the camera's AWB system picks it up as "white".
White LEDs are fine - at least in my application. I've used a Surefire L4 and U2 as illumination for closeup photos of equipment and the camera's AWB system picks it up as "white".
Re: want to mimic sunlight w/o heat for indoor pho
The problem with all of the alternatives listed is that they have a discontinuous color spectrum or the balance is very different from sunlight. Sunlight is continuous with a color temperature in the 5000-6000 deg. K range. If you want best color rendition, unfortunately the alternatives are:
flash units with daylight film or digital camera white balance set to set to daylight
or
incandescent lighting (best with specialty bulbs) with tungsten balanced film or digital camera white balance set to incandescent.
The problem with all of the alternatives listed is that they have a discontinuous color spectrum or the balance is very different from sunlight. Sunlight is continuous with a color temperature in the 5000-6000 deg. K range. If you want best color rendition, unfortunately the alternatives are:
flash units with daylight film or digital camera white balance set to set to daylight
or
incandescent lighting (best with specialty bulbs) with tungsten balanced film or digital camera white balance set to incandescent.
ErickThakrar
Enlightened
Re: want to mimic sunlight w/o heat for indoor pho
Actually, you can get the Daylight fluorescent flood lamps and they will come VERY close to sunlight. It's really provides some excellent color rendition. Make sure they're the 5000 Kelvin type lamps.
Actually, you can get the Daylight fluorescent flood lamps and they will come VERY close to sunlight. It's really provides some excellent color rendition. Make sure they're the 5000 Kelvin type lamps.
Re: want to mimic sunlight w/o heat for indoor pho
Actually they do not come close to daylight. Like all fluorescents, they have a discontinuous color spectrum. They have peaks in the red and blue parts of the spectrum to fool the eye into thinking that they are like daylight. Below is a link to a site with spectrums of a number of fluorescent bulbs, including several so-called daylight bulbs. Unlike daylight, all of these bulbs have major peaks and gaps at various points in the spectrum and will give a color cast (usually green or yellow green)to pictures taken using strictly fluorescents.
http://www.geocities.com/Heartland/Hills/2637/index.html
Click on "Fluorescent Light Comparison" to see the spectrum for a number of fluorescent bulbs, most of which have a color temperature in the 5000 to 6500 deg. range.
Actually they do not come close to daylight. Like all fluorescents, they have a discontinuous color spectrum. They have peaks in the red and blue parts of the spectrum to fool the eye into thinking that they are like daylight. Below is a link to a site with spectrums of a number of fluorescent bulbs, including several so-called daylight bulbs. Unlike daylight, all of these bulbs have major peaks and gaps at various points in the spectrum and will give a color cast (usually green or yellow green)to pictures taken using strictly fluorescents.
http://www.geocities.com/Heartland/Hills/2637/index.html
Click on "Fluorescent Light Comparison" to see the spectrum for a number of fluorescent bulbs, most of which have a color temperature in the 5000 to 6500 deg. range.
Re: want to mimic sunlight w/o heat for indoor pho
Good job of explaining, lenny45!
The so called daylight flourescent bulbs, and there are several of them at different spreads of the spectrum, are great for plants and the really expensive ones are for reptiles.
Lenny also nailed the answer earlier when he recommended tungsten film/bulbs or flash/digital.
Most camera stores carry a dark blue bulb meant to simulate daylight on daylight film but usually (IMHO) leave a somewhat noticable warm cast to the photos. If you have a really good operator at your photo lab, they can correct for most of it. I have yet to see a one hour photo shop or Wal Mart style send away lab take the trouble to do so. The best choice in send away developing is Kodak. Select the deluxe developing (read most expensive) and they will color correct as much as is possible.
There are also some very inexpensive flash units on eBay that work reasonably well if you have a light meter to measure exposure. If it is in your budget, get a unit that has a slave feature so it will fire when the camera flash fires, thereby providing fill to balance the lighting and make a more pleasing photograph.
Arlen
Good job of explaining, lenny45!
The so called daylight flourescent bulbs, and there are several of them at different spreads of the spectrum, are great for plants and the really expensive ones are for reptiles.
Lenny also nailed the answer earlier when he recommended tungsten film/bulbs or flash/digital.
Most camera stores carry a dark blue bulb meant to simulate daylight on daylight film but usually (IMHO) leave a somewhat noticable warm cast to the photos. If you have a really good operator at your photo lab, they can correct for most of it. I have yet to see a one hour photo shop or Wal Mart style send away lab take the trouble to do so. The best choice in send away developing is Kodak. Select the deluxe developing (read most expensive) and they will color correct as much as is possible.
There are also some very inexpensive flash units on eBay that work reasonably well if you have a light meter to measure exposure. If it is in your budget, get a unit that has a slave feature so it will fire when the camera flash fires, thereby providing fill to balance the lighting and make a more pleasing photograph.
Arlen
Re: want to mimic sunlight w/o heat for indoor pho
[ QUOTE ]
lenny45 said:
Actually they do not come close to daylight. Like all fluorescents, they have a discontinuous color spectrum.
[/ QUOTE ]
While that's indeed true, I'm not sure it matters. What matters is the bandpass of the three colors of pixels in the camera, right? From what I've been told they are quite narrow, wider than the phosphors on your monitor (the one that doesn't seem to have trouble reproducing the photo...), but still relatively narrow. That being the case, light outside those three narrow bands just doesn't register.
Doug Owen
[ QUOTE ]
lenny45 said:
Actually they do not come close to daylight. Like all fluorescents, they have a discontinuous color spectrum.
[/ QUOTE ]
While that's indeed true, I'm not sure it matters. What matters is the bandpass of the three colors of pixels in the camera, right? From what I've been told they are quite narrow, wider than the phosphors on your monitor (the one that doesn't seem to have trouble reproducing the photo...), but still relatively narrow. That being the case, light outside those three narrow bands just doesn't register.
Doug Owen
Re: want to mimic sunlight w/o heat for indoor pho
Actually, the sensors in digital cameras have a very wide sensitivity, going from the IR to UV. Photographers take advantage of this and shoot IR and UV photos with digital cameras using the appropriate filters to block out the visual (to the human eye) part of the spectrum.
The bottom line with using fluorescents or a bank of multi-colored LEDs is this. If there is no light in a given range of wavelengths or if the level is below the threshold of sensitivity of the CCD or CMOS sensor, the camera cannot record light in that range. The end result is the picture generated will not be representative of the colors and density of the subject because any object colored in that range will not be recorded accurately.
Fluorescent lighting is one of the most difficult of the commonly used lighting methods to get accurate color rendition in photographs, whether using film or digital, which is one reason why photo studios use electronic flash or incandescent lighting. A bank of LEDs with gaps in the spectrum would present similar problems.
I have in use in aquariums at this time three different brands of "daylight fluorescent" bulbs. One gives a purple tint, the second a yellow tint and the third a blue-green tint to the areas illuminated by them. All show a less than realistic shade of green on all plants.
Actually, the sensors in digital cameras have a very wide sensitivity, going from the IR to UV. Photographers take advantage of this and shoot IR and UV photos with digital cameras using the appropriate filters to block out the visual (to the human eye) part of the spectrum.
The bottom line with using fluorescents or a bank of multi-colored LEDs is this. If there is no light in a given range of wavelengths or if the level is below the threshold of sensitivity of the CCD or CMOS sensor, the camera cannot record light in that range. The end result is the picture generated will not be representative of the colors and density of the subject because any object colored in that range will not be recorded accurately.
Fluorescent lighting is one of the most difficult of the commonly used lighting methods to get accurate color rendition in photographs, whether using film or digital, which is one reason why photo studios use electronic flash or incandescent lighting. A bank of LEDs with gaps in the spectrum would present similar problems.
I have in use in aquariums at this time three different brands of "daylight fluorescent" bulbs. One gives a purple tint, the second a yellow tint and the third a blue-green tint to the areas illuminated by them. All show a less than realistic shade of green on all plants.
