I recently took the advice of someone trying to help with my photography, and ditched the incandescent bulbs. The last couple of bowls I photographed were lighted by CFL "daylight" bulbs, and there is some improvement. The daylight CFLs are not terribly expensive, as far as CFLs go.
I've run across some CFL bulbs that seem to be specifically applicable to photography, or so the labeling of some of these bulbs does mention photography. Some don't specifically mention photography, but come up in an Amazon search for "photography CFL bulb". Descriptive words like "daylight balanced, pure white, and full spectrum" are being used. These are a bit more expensive. The bulbs I'm currently using say "daylight", but not "daylight balanced"......nor do they say anything about full spectrum, or pure white......
Just wondering if anyone here has any comments, preferences, or other information on these bulbs for photography use. Should I see any difference between the daylight CFL bulbs I've used recently......, and those that mention daylight balanced, full spectrum, or pure white bulbs?
One thing I didn't know is the light output for wattage rating of a CFL is roughly 1/4th that of an incandescent bulb. A 25w CFL is about the same as a 100w incandescent bulb.
Thanks......
ooc
I would check with reputable dealers such as B&H and Adorama to see which CFL's are made for photography. However, FYI there is no such thing as a true full spectrum CFL. Fluorescent lights work by ion discharge which means that they output light at discrete narrow-band wavelengths. The better ones use a mixture of phosphors and gasses to emit light at a large number of discrete wavelengths, but still it won't be a continuous spectrum of light. The good news is that our eyes have a tristimulous response to light so a mixture of red, green, and blue light can cover the portion of human vision to which we are most sensitive. However because each kind of light source has missing portions of spectrum in its output, there will still be a difference in how we perceive some colors when we compare these sources against each other or against natural daylight which is the "gold standard".
Most of the time all those technical details aren't critically important. Our eyes and also digital camera sensors are sensitive to a very wide gamut of colors, but by the time the color information is digitized and converted to a file that our computers recognize, the range of color information has already been reduced to a fraction of the color gamut that we are able to see. Besides that, our computer monitors and color printers limit the range of displayable colors even further. The good news is that the amount of color information is still plenty adequate for a color image to look faithful to the original colors
IF the color of white looks white to our eyes. If things that are supposed to look white look orange or green or blue then the image will look terrible. That is why photographers are so interested in achieving a good white balance.
There are various ways of setting white balance and generally speaking just about any good high quality light source will give us good color fidelity if we go to the trouble to make sure that the white balance is good.The industry standard for high noon daylight white is 5000K, but for the average person using a typical computer monitor, a color temperature of 6500K tends to look better. So that is the color temperature that is used by most standard color profiles. Each time that you shoot your turnings, first get an in-camera calibrated white balance and the results should be fine.
Don't put too much stock in the equivalency ratings that you see on the package of CFL's. A 13 watt bulb says it is a 60 watt "replacement" -- not really equal in light output. One difference that is important is that the light from a CFL radiates mostly to the side while an incandescent bulb is closer to radiating omnidirectionally. This means that you might need to reconfigure your lighting or add more light or increase the exposure time.
Well, daylight should be in the 5000-6200 Kelvin range.
CFLs will work fine (John Lucas has tested a bunch) but the manufacturers often stretch the truth. CFLs, in this application, need to warm up, maybe 10 minutes. They have been known to change color temperature while they are turned on, not something that you or I will notice. Probably best to do a custom white balance when photographing with them.
But the biggest stretch is usually the power output compared to incandescent and such. You can still get a lot of watts in a socket without the heat you would normally get with incandescent. I shoot incandescents with 500 watts on the left and right side and 250W on top. The issue with those (photo bulbs) is they have about a 6-10 hr lifespan. And they get real hot, enough to melt the plastic diffusers on the side of the tent.
If you look through the offerings at Cowboy Studio and Adorama you can get a good feel for the bulbs available in CFL.
I really want to go LED, but the descent ones are in the $1500+ area for a three light setup.
I think that I must be using the same photo bulbs that you are using. They are blue colored, have a color temperature of 4800K, get hotter than the dickens at 500 watts apiece, and only last 6 - 8 hours, and cost about $12 apiece -- so figure two dollars per hour per bulb not counting the cost of electricity. I still have a stash of them, but am considering other options when they all burn out. Just to illustrate how hot they get, the glass globe on one of mine melted once when it didn't get enough cooling air. I have wondered about LED lights, but their narrow-band spectral content makes me concerned about color fidelity. I really have not looked at the high end pricey ones.
