Flourescent lighting

smilesforlife

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I just changed the location of my studio and my previous was pot lights.. white walls..high ceiling.. new studio is fluorescent lights with cream walls, low ceiling.. had to change my kelvin temps in the new studio, have never before. I do not use strobes or studio lighting but have always bounced my flash. Always,, even in ppls homes. always been happy.
So frusterated as my images are no longer consistant in the new studio.. same settings one could be yellowish, one could be perfect.. I wondered if it was because I was bouncing my 580 EX flash off the lighting... some say it's the flickering bulb.. I don't want to put money into changing anything until I am completely sure. Bulbs are not cheap and fixtures to change are $300 per fixture and there is 7.
 

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Your color shifts are due to the alternating-current cycling. If you live where it's 60Hz, your fluorescent lamps will dim 120 times a second. When they dim, the color output changes slightly. Your camera is picking up this difference when you use a high enough shutter speed.
 

WayneF

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I just changed the location of my studio and my previous was pot lights.. white walls..high ceiling.. new studio is fluorescent lights with cream walls, low ceiling.. had to change my kelvin temps in the new studio, have never before. I do not use strobes or studio lighting but have always bounced my flash. Always,, even in ppls homes. always been happy.
So frusterated as my images are no longer consistant in the new studio.. same settings one could be yellowish, one could be perfect.. I wondered if it was because I was bouncing my 580 EX flash off the lighting... some say it's the flickering bulb.. I don't want to put money into changing anything until I am completely sure. Bulbs are not cheap and fixtures to change are $300 per fixture and there is 7.


Based on technology change in the 1990s, fluorescent lights are either old or new.

Old ones use magnetic ballasts, and new ones use electronic ballasts.
Speaking of builtin larger ceiling fixtures, which might be either type. Complicated, because some older magnetic ballast is still sold. Compact CFL bulbs use electronic ballast.

The old ones with magnetic ballast will flicker with the line voltage, either 60 Hz (North America) or 50 times a second (much of rest of world). Technically, the flicker is at twice that rate. Our shutter speed needs to be either that exact 1/60 or 1/50 second, or perhaps exactly twice faster. But NOT any inexact partial multiple. Because, unless our shutter mimics the same frequency, or exactly double it, we capture partial cycles and will see serious random color shift. Every shot will not be the same, often yellowish, brownish.

New electronic ballasts are tremendously faster, maybe 20,000 Hz, and are not any issue about flicker.

See Color Filters on Flash

for details of a simple shutter test (which intentionally does it wrong to cause the problem) to decide which your your lights are. Don't use Auto white balance for the test. Doesn't really matter which WB is used, we are just looking for differences in several shots, but Auto WB tends to hide differences.

Using the shutter speed same as the cycle duration works. Or just the ballasts can be replaced (less expensive), the rest of the old fixture is not a problem.
 
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smilesforlife

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Thanks so much for chiming in and helping this all make sense to me.. it's still rather confusing.
How does one person shoot under 1/125 when shooting children who non stop move.
I am willing to try whatever it takes if I know it will work.
 

dennybeall

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If you're handy and allowed to by the building owner, you can open one of the fixtures and see which ballast is in there. The old ones are big and very heavy (for 2 -8 foot bulbs the ballast will be about a foot long and 2" X 2"). You can buy a new electronic one at Home Depot or Lowes and change it out. It's very easy but the new electronic ballasts are not cheap. I've got over 200 of the fixtures at my self-storage facility so have changed out a bunch of them over the years.
 

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How does one person shoot under 1/125 when shooting children who non stop move.

Well, magnetic fluorescent is far from the best lighting, but you said bounce flash, and flash is fast (faster than shutter speed - the shutter just has to be open to pass the flash), so more emphasis on flash power will stop action pretty well. If actually needed, you could add a second flash unit. You would want full size regular speedlights (like the 580), not the little toy ones for bounce.

The continuous light is what lets slower shutter speed blur action that the flash could have already stopped. Continuous light cannot stop action, but the speedlight flash can. In this case, it is NOT the faster shutter speed that stops the motion anyway. It is the flash that stops the action, and instead faster shutter just keeps out the contribution of the continuous light that could blur whatever motion that the fast flash already stopped.

But in this case, faster shutter speed messes up the flicker situation, but you can turn off Auto ISO, and use lower ISO (maybe ISO 400 for bounce, or ISO 200 is sometimes possible), and do pretty well (lower ISO keeps out the continuous, but the flash power can simply be turned up to compensate). The bounce will usually light up the whole room in the same way the ceiling lights could.

Mixing flash and fluorescent is bad anyway, because they are different colors. We can only set one White Balance, so more flash and less fluorescent is good for that reason too, with Flash white balance.
 
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DB_Cro

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Thanks so much for chiming in and helping this all make sense to me.. it's still rather confusing.
How does one person shoot under 1/125 when shooting children who non stop move.
I am willing to try whatever it takes if I know it will work.

You can freeze motion using 2nd curtain flash sync at virtually any shutter speed, the flash will "bake in" the image.
I've been shooting like that in nightclubs (people dancing), often at 1/4 to 1/8th of a second.

Only need to be sure that the flash output is above the various ambient lights that might be flying around or you might
get ghosting.
 

WayneF

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2nd or rear curtain sync does NOT "bake in the flash". Each pixel simply accumulates all the light that hits them, and shows the one value of total accumulation. It does not matter to the total when it occurred.

Since the 2nd or rear curtain sync flash occurs at the end of the open shutter duration, it does cause any motion blur recorded during the longer continuous light exposure to be located "trailing" the moving subject instead of leading it out in front. Looks very much more natural. Examples at Flash Sync mode, including Rear Curtain Sync
 

DB_Cro

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I adjusted my post to the obvious level of expertise of the person who asked.
I think he got the point.
 

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Mixing flash and fluorescent is bad anyway, because they are different colors. We can only set one White Balance, so more flash and less fluorescent is good for that reason too, with Flash white balance.

You can get colour balancing gels for either the fluorescent lights or the flash to reduce the WB issue. Might be a pain to get right & it won't solve it if there's flicker involved.
It MIGHT be that shooting a couple of test videos could check for flickering. I think they'd show quite well if the video frame rate is at odds with the mains cycle. Many cameras allow video rate to be adjusted to work with 60Hz or 50Hz.
 
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smilesforlife

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So what I do know is the bulbs are 4100k is the flourescent bulb temp. They put 3700k in my waiting room to see if it was better on my head (migraines) and the room looks yellow. I can find out whatever I should ask.
Yesterday I shot with white backdrop.. and all pics looks pretty good,, I was happy.
I didn't change anything so this didn't help me figure things out..
1/160 3.5 ISO 250 RAW bounced 580 Ex no window light
 

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Are all of your shots consistently the correct color now?
 

WayneF

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That bad?

Not bad at all. You said pretty good, and happy, and I'd agree, so not sure of any question? I suppose asking why it wasn't bad as before? I don't know enough about the two situations to venture a guess. Assuming same overhead fluoresecnt with bounce flash. It could be possible that you randomly caught the flicker at its best point (although I don't detect much color difference issue from the flash). Or maybe the flash exposure was strong enough to overwhelm the ambient exposure so that fluorescent didn't matter? Or maybe vice versa?

If you want to discuss it, how was white balance done?

I can see that much of the light is from overhead, which could be bounce, or or it could be ceiling lights, or both. I can't tell the difference. Because the color is better, I'm guessing it is mostly flash, and ought to be good. But I can't tell if flash is main light or just a low fill level.

You are getting a pretty good frontal fill, which seems stronger than the catchlights in the eyes would suggest it should be. Was a bounce card or dome used on the bounce flash? I'm thinking not, and that makes me think the overhead lights are dominant and flash is just fill? But I don't know, I wasn't there.

If I were wondering and had opportunity, I'd try some more test pictures. Don't need the family for a subject, or even the background for this, just need to be in the same room with the same lights... a photo of a chair or something would work, if all else was the same. Put a piece of plain white copy paper in it to judge color. Use exactly the same location positions and camera settings, but a picture WITHOUT the flash would tell us how much the fluorescent overhead lights were contributing. It will either be a dark picture, or reasonably exposed (at same manual settings), depending on how much contribution from the overhead lights. If pretty dark, that's why the flash picture was good, fluoresents were not much factor.

Or if a significant old style fluorescent contribution, we already know 1/160 second is no good, so then also try 1/60 (better) or 1/125 (probably pretty good) (if assuming North America). The camera actually implements 1/64 and 1/128 for these shutter speeds, but the power is 60.0 Hz. So close, but not perfect, and anything else is Not good.

Because 60 Hz electrical current passes through zero voltage 120 times a second, and these lights react. 1/160 second is 3/4 of one of the 120 Hz cycles, and this 3/4 cycle is randomly positioned every shot. The fluorescent color will vary 120 times a second with magnetic ballast, randomly with respect to your shutter. Slowing the shutter to exact multiples is better, because the partial cycle captured will be minor compared to few more complete cycles also captured.

The best way to fix magnetic ballast fluorescent lighting is to NOT use it for photography. You can replace with electronic ballasts to eliminate the flicker, but you would still have fluorescent lights.

Hold this shutter speed but do any proper exposure, without flash. Don't use Auto WB, which will just confuse and hide things. The color should be better, and repeatable then in every subsequent test. Take 5 or 6 of same, to assure there is no variance now. Later when adding flash, overhead color will still different than flash color though. I suspect you really want to use one or the other lights, but not not both.

When adding flash, 1/60 second is fine if using flash, flash is faster and does not care what the shutter speed is. 1/120 will keep out more of the fluoresecent, which is then likely a better color without it, since it won't be the same color as the flash.

I would also try another test (of the chair, etc) with overheads turned off, using only the flash (same settings). I seriously doubt that one will be a black picture. With these tests and comparisons, you will know more about the situation, about what ratio of each you are dealing with. Or a light meter would do much of the same, except for color.
 
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