screw in LCD or fluorscent bulbs

[chauncey]

For cheap Home Depot light stands, has anyone used the screw-in fluorscent or LCD bulbs. Are they any better than regular bulbs?

[c71clark]

Better how? They would use less power and generate less heat, so that's better I guess. Color balance would have to be managed, but you'd do that with regular bulbs too, so they;'re even there. Light output would be generally even if you get the right bulbs, but being only able to use 1 bulb will limit you in how much light you throw out with fluorescent bulbs. There are more options for incandescent than fluorescent.

[chauncey]

I was thinking more about color temperature.

[SkipD]

The light from fluorescent lamps often has a distribution of color intensities that is not comparable to other light sources and can cause problems with colors in images. For "hot" lights, I would suggest that you either research fluorescents that are made for photography use or use tungsten lights.

Unfortunately, I have no experience with using fluorescent lights in the studio so I cannot tell you where to look for the special fluorescent lights for photo use.

Fluorescent lights that are driven at the power line frequency can cause horrendous problems with both intensity and color if you try using fast shutter speeds. For those, you want to use very specific shutter speeds (1/120, 1/60, 1/30, etc., for 60Hz power) to avoid the problems.

[440roadrunner]

Skip, are you sure that specific shutter speed even has anything to do with 60hz? You are not tripping the shutter with any kind of electronic connection to line power, so the shutter could open "at any time" relative to line power.It seems to me, that if the shutter "happens" at the time the sine wave is at a zero crossing point, and if all/any flourescent lamps are on the same line (circuit), they could be dim or out at the time the shutter fires, regardless of a specific speed.Seems to me, generally, the slower the better, I.E. compared to taking pictures on a TV set and getting the scan lines in picture.I'm certainly no expert, but it certainly seems that color temp is going to be a problem, as well as the "black light" effect from flourescence of everything from teeth, skin, and white linen. Not only that, but flourescent lamps have a pretty wide range of color just within themselves.

[SkipD]

Skip, are you sure that specific shutter speed even has anything to do with 60hz? You are not tripping the shutter with any kind of electronic connection to line power, so the shutter could open "at any time" relative to line power.It seems to me, that if the shutter "happens" at the time the sine wave is at a zero crossing point, and if all/any flourescent lamps are on the same line (circuit), they could be dim or out at the time the shutter fires, regardless of a specific speed.Seems to me, generally, the slower the better, I.E. compared to taking pictures on a TV set and getting the scan lines in picture.I'm certainly no expert, but it certainly seems that color temp is going to be a problem, as well as the "black light" effect from flourescence of everything from teeth, skin, and white linen. Not only that, but flourescent lamps have a pretty wide range of color just within themselves.The shutter speeds I listed (1/120, 1/60, 1/30 or 1/15 second) will keep the shutter open for a full half-cycle of the power sine wave or precise multiples of a half-cycle.

It does not matter when within the power cycle that you start the exposure, though. You can start the exposure at any time during the half-cycle. What does matter is that you keep the shutter open long enough to capture all of the light produced by the fluorescent light during a half-cycle of the power or an exact multiple of half-cycles. That way, the image shows the average of all of the changes in color and intensity that will be given off by the fluorescent light.

For you folks using 50Hz power, the shutter speeds you would need would be 1/100, 1/50, or 1/25 second.

Fortunately, a lot of today's fluorescent lights are using electronic ballasts with a frequency that is a lot higher than the power line frequency. These lights do not cause the same problems as those with a (usually magnetic) line-frequency ballast.

There are a number of other lighting types that exhibit the same sort of problem at higher shutter speeds. These are all gas-discharge lamps and are fired at the power-line frequency.

[Mark_48]

I'm presently constructing a budget 6 bulb light bar that I'm going to try using compact flourescent bulbs that I got from Walmart. The bulbs are GE Daylight 6500K 26W and have a CRI (Color Rendering Index) of 82. The CRI number is an indication of the continuity of the color spectrum that the lamp puts out. The higher the number, the less gaps in the spectrum. Ideally for photographic applications it should be 90 or greater. The 6500 K color temp might be a bit on the cool side, but if I manually WB they might be OK. These can't be controlled with a dimmer, so I'll use a switch to control how many are on. Some preliminary test shots with a single bulb seemed to not look too bad.

Link to Specs: Compact Flourescent (http://genet.gelighting.com/LightProducts/Dispatcher?REQUEST=CONSUMERSPECPAGE&PRODUCTCODE=85397&BreadCrumbValues=Lamps_Compact Fluorescent_Self-Ballasted_Spiral®_T3&ModelSelectionFilter=)

[SkipD]

I'm presently constructing a budget 6 bulb light bar that I'm going to try using compact flourescent bulbs that I got from Walmart. The bulbs are GE Daylight 6500K 26W and have a CRI (Color Rendering Index) of 82. The CRI number is an indication of the continuity of the color spectrum that the lamp puts out. The higher the number, the less gaps in the spectrum. Ideally for photographic applications it should be 90 or greater. The 6500 K color temp might be a bit on the cool side, but if I manually WB they might be OK. These can't be controlled with a dimmer, so I'll use a switch to control how many are on. Some preliminary test shots with a single bulb seemed to not look too bad.

Link to Specs: Compact Flourescent (http://genet.gelighting.com/LightProducts/Dispatcher?REQUEST=CONSUMERSPECPAGE&PRODUCTCODE=85397&BreadCrumbValues=Lamps_Compact Fluorescent_Self-Ballasted_Spiral®_T3&ModelSelectionFilter=)Could you run a test with those to prove whether they are using a high frequency ballast? Try using a shutter speed up in the 1/300 second or faster range and shoot a quick series of shots. If all of the shots are illumated the same and have the same color, then those lights should be much easier to use for photo purposes than those with line-frequency ballasts.

[Mark_48]

Real quick setup to check what Skip asked. I let the camera auto white balance. Wide range of shutter speeds with no apparent problems. Color rendition isn't too bad for AWB.

[SkipD]

Mark, what I was suggesting is a rapid set of shots at the same (preferably MANUAL) exposure setting. A fixed white balance setting would also be much better for the test I suggested, rather than using AWB.

The purpose of the test is to see how consistent the exposure and colors are from shot to shot with precisely the same camera settings to see if the lighting is of a type that can mess you up or not. If you let the camera do things automatically, the test of the lighting itself is less valid.

[Mark_48]

Misread what you meant by a series at different shutter speeds. Morning coffee hadn't quite kicked in.

I'll try a reshoot later, but I did check one of the lamps using an oscilloscope probe adjacent to the bulb and it was singing along at about 100Khz, so that sort of says it's a high frequency ballast onboard.

[SolidxSnake]

I use 5500°K CFL bulbs in my room and in a few other rooms in my house. These CFL bulbs also come in different color temps, anywhere from 2700°K to 5500°K I believe.

And btw, LCD bulbs isn't the correct term... for anything. I believe you mean LED bulbs, which are superior to incandescent bulbs in every matter IMO. They don't have any frequency problems as CFL bulbs (Though I believe all the CFLs in my house use high-frequency ballasts so that doesn't matter much either), they last ridiculously long, and they're not too expensive either (I think they're cheaper than CFL bulbs). However, I've never seen them for sale at my local Home Depot.

[SkipD]

I'll try a reshoot later, but I did check one of the lamps using an oscilloscope probe adjacent to the bulb and it was singing along at about 100Khz, so that sort of says it's a high frequency ballast onboard.I am guessing, without any testing, that the compact fluorescent lamps use a high-frequency electronic ballast. That type would be a lot smaller than a magnetic ballast or even an electronic ballast working at power line frequency.

Hopefully, readers of this thread latch on to the possibility of problems with fluorescent lighting for photography, though, as it can be nasty. Lighting in school gymnasiums is often horrible for photography, as an example.

[SolidxSnake]

I am guessing, without any testing, that the compact fluorescent lamps use a high-frequency electronic ballast. That type would be a lot smaller than a magnetic ballast or even an electronic ballast working at power line frequency.

Hopefully, readers of this thread latch on to the possibility of problems with fluorescent lighting for photography, though, as it can be nasty. Lighting in school gymnasiums is often horrible for photography, as an example.



For those who might not know, those nice squiggly bulbs that screw into a standard lightbulb socket where you put in an incandescent bulb are called CFL (Compact FLuorescent).

[440roadrunner]

You can start the exposure at any time during the half-cycle. What does matter is that you keep the shutter open long enough to capture all of the light produced by the fluorescent light during a half-cycle of the power or an exact multiple of half-cycles. That way, the image shows the average of all of the changes in color and intensity that will be given off by the fluorescent light.

For you folks using 50Hz power, the shutter speeds you would need would be 1/100, 1/50, or 1/25 second.

Fortunately, a lot of today's fluorescent lights are using electronic ballasts with a frequency that is a lot higher than the power line frequency. These lights do not cause the same problems as those with a (usually magnetic) line-frequency ballast.

There are a number of other lighting types that exhibit the same sort of problem at higher shutter speeds. These are all gas-discharge lamps and are fired at the power-line frequency.
Can you provide some documentation, or a link to back that up? I'd like to read further about this. Is there an official "term" that describes this condition?

[Mark_48]

.........Hopefully, readers of this thread latch on to the possibility of problems with fluorescent lighting for photography, though, as it can be nasty. Lighting in school gymnasiums is often horrible for photography, as an example.

Don't most gymnasiums use sodium vapor fixtures or similiar? I don't recall any I've been in recently using fluorescents. Maybe the more energy efficient facilities may have them(?) I agree anything that isn't a continuous spectrum is tough to shoot and worse with film.

SolidxSnake, Did you find the 5500K CFL's locally or did you have to order them somewhere. I've seen them online, but they were a little pricey. The 2 pack of the GE 6500K at Walmart was about $8, so I'm not out much money if they don't work out for photo lighting. I can always use them for house lighting.

[Mark_48]

A 50 or 60 Hz flourescent with a magnetic ballast actually flickers, but it's fast enough that the eye doesn't percieve it. The flicker is due to the alternating current changing from a peak value, crossing through a zero value, and then to another peak. The phosphors in the bulb are being turned on to off to on at each cycle of voltage, but again it's too fast for the eye to detect. A 60Hz voltage cycles at the rate of 1/60th of a second and 50Hz at 1/50th of a second, hence the shutter speed numbers and multiples that Skip came up with. A camera with a fast shutter speed could concievably pick up this change and it may be evident as a shift in color as the phosphor loses or gains its excitation or by an underexposed image. The high frequency electronic ballasts provide an AC voltage which changes at such a high rate that the on-off-on rate of the phosphors is faster than the camera shutter speed can resolve. In the case of the CFL I looked at with oscillscope it was around 100Khz (maybe that's why my dog barks when I turn it on) and this changes at 1/100000 of a second.

A link about flourescents....
http://ergonomics.about.com/od/ergonomicbasics/ss/fluorproblems.htm

[SolidxSnake]

Don't most gymnasiums use sodium vapor fixtures or similiar? I don't recall any I've been in recently using fluorescents. Maybe the more energy efficient facilities may have them(?) I agree anything that isn't a continuous spectrum is tough to shoot and worse with film.

SolidxSnake, Did you find the 5500K CFL's locally or did you have to order them somewhere. I've seen them online, but they were a little pricey. The 2 pack of the GE 6500K at Walmart was about $8, so I'm not out much money if they don't work out for photo lighting. I can always use them for house lighting.



I got the CFLs at a local Home Depot, they also carry 3-4 different color temps of the same bulbs. I picked up a 4 or 6 pack of the 5500°K bulbs, they don't have many of that color in stock, but they stock the lower temps excessively.

[DDCSD]

And btw, LCD bulbs isn't the correct term... for anything. I believe you mean LED bulbs, which are superior to incandescent bulbs in every matter IMO. They don't have any frequency problems as CFL bulbs (Though I believe all the CFLs in my house use high-frequency ballasts so that doesn't matter much either), they last ridiculously long, and they're not too expensive either (I think they're cheaper than CFL bulbs). However, I've never seen them for sale at my local Home Depot.

Actually, they run about $60 per bulb and have horrendous light output. Good for a table lamp, not even an option if you need decent light output unless you want to spend $100+ for a spotlight type bulb. Even then the light output is not very good except in a very concentrated beam.

[SolidxSnake]

Actually, they run about $60 per bulb and have horrendous light output. Good for a table lamp, not even an option if you need decent light output unless you want to spend $100+ for a spotlight type bulb. Even then the light output is not very good except in a very concentrated beam.


$60 per bulb? Where the hell are you looking, because you're getting ripped off. I got 6 packs of 5500°K bulbs for around... let's say $15-$20 (I forget the exact price).


Edit: Crap, just realized you were speaking about LED lightbulbs. Sorry bout that.

[DDCSD]

$60 per bulb? Where the hell are you looking, because you're getting ripped off. I got 6 packs of 5500°K bulbs for around... let's say $15-$20 (I forget the exact price).


Edit: Crap, just realized you were speaking about LED lightbulbs. Sorry bout that.

Ha, yeah that might be a bit high for a CFL. :lol:
Only thing I hate about CFL's is the start-up time, especially in my cold garage.

[HoosierJoe]

Thanks for the thread. I have been wondering the same thing myself. I have the exact CFL bulbs you are talking about thoughout my house (which also serves as our business). We take pics indoors at times for our business and I generaly use the AWB setting or the FL for white balance we also have a lot of windows so there is natural lighting mixed in. Of course there is some pp with any photographs we use. Seems to work fine.

What I believe you are asking is can these bulbs be used in studio. Your test shots look acceptable to me. I am interested in this also. If it works it sure beats the, uh you know, out of photofloods.

[SolidxSnake]

Only thing I hate about CFL's is the start-up time, especially in my cold garage.


Mine start up just as fast as my old incandescent bulbs. That said, it does take a bit of time for them to warm up and get to full output but they do start-up instantly.

[DDCSD]

That's what I meant, the time it takes them to get to full brightness.