Using Flash in Fluorescent Lit Rooms

[Stagecoach]

I'm presently planning a job that will entail shooting people with technical equipment in smallish rooms/labs that are lit by fluorescent ceiling lights. Having viewed the locations it appears all lights have 'daylight' tubes.

Shooting time will be between 1/2 hour before sunrise to about 1 hour after so the influence of outside light through windows is going to be variable.

I intend to use flash, mainly bounced and luckily ceilings are low and white and there are no garish coloured walls.

I'm aware SS needs to be kept at or below mains frequency and wondering if there's anything else I should be considering regarding colour balance/correction at the time of shooting.

Grahame

[Manfred M]

I would try one of two approaches:

1. My preferred approach would be to either eliminate or overpower the fluorescent light with flash so that it has no impact on the image. Is shooting with the lights off an option? As you are planning to bounce the light it sounds like that should work and white walls and ceilings are definitely working in your favour.

The best way to determine the contribution of the ambient light to the image is to use the identical settings as with the flash shot to take a shot without any flash. If the image is black you will know that the ambient room light is not contributing to the image.

2. if you need the light from the fluorescent lights as a light source, try gelling your flash with a CTS (Colour Temperature Straw) gel. That would get the colour balance between the two light sources more closely aligned. I don't know if you can get CTS gels in Fiji.

The main issue with fluorescent lights is that there is no consistency between the quality of light from different tube manufacturers. They all have different phosphour coatings and tubes labeled as "daylight" from different manufacturers can (and do) have significantly different spectral characteristics.

[Stagecoach]

Thank you Manfred

I would try one of two approaches:

1. My preferred approach would be to either eliminate or overpower the fluorescent light with flash so that it has no impact on the image. Is shooting with the lights off an option? As you are planning to bounce the light it sounds like that should work and white walls and ceilings are definitely working in your favour.

The best way to determine the contribution of the ambient light to the image is to use the identical settings as with the flash shot to take a shot without any flash. If the image is black you will know that the ambient room light is not contributing to the image.

Elimination of the florescents will not be possible as full time lighting is required by the team working to a tight timescale.

Overpowering the flourescents I suspect is possible as the room areas are small but I'm hoping to produce images that have a more balanced look than those taken with a single light source. I considered using more than one flash but suspect I'll be changing positions too often.

I recently set up a front button to switch off flash which I found really useful and quick when assessing ambient contribution with fill flash when shooting pre sunrise recently.

2. if you need the light from the fluorescent lights as a light source, try gelling your flash with a CTS (Colour Temperature Straw) gel. That would get the colour balance between the two light sources more closely aligned. I don't know if you can get CTS gels in Fiji.

I have just acquired an SB-910 complete with coloured filters and have an area outside lit by daylight flourescents so I can test that out tonight.

The main issue with fluorescent lights is that there is no consistency between the quality of light from different tube manufacturers. They all have different phosphour coatings and tubes labeled as "daylight" from different manufacturers can (and do) have significantly different spectral characteristics.

This will be something I'll just accept and I'm happy to spend time in post if necessary.

For info, the mosquito shots I took a few months back have led to this project which entails photographing the packing and loading of chilled mosquitos at the labs which are then taken offsite to be dispersed by UAV (drone).

[Manfred M]

I have just acquired an SB-910 complete with coloured filters and have an area outside lit by daylight flourescents so I can test that out tonight.

If the SB-910 has a similar gel set to the SB-900, then the green toned ones are designed to be shot with fluorescents. I generally avoid having to work with that type of light, so I have never tested them out (I own an SB-600 and and SB-900). I have access to enough lights that overpowering ambient is usually no issue

If time is tight and I need to shoot without ambient lights I will have someone man the light switch for the room and will set up the shot, have the light turned off and will have it turned on again as soon as the shot has been taken. I'm not sure it that is an option for you.

Worst case, going B&W covers a lot of lighting sins...

[rpcrowe]

This is an interesting read: https://www.flickr.com/groups/350343...7684489615124/

Some cameras such as the Canon 6D Mark-2 have flicker detection which only works fr stills, not video...

I would also try to establish a white balance using a target like the Whibal Card and either establish a custom white balance or use the target to get close to white balance in PP using Adobe Camera RAW or Lightroom.

In the film days, a common practice was to gel the flash with a green gel to mimic the fluorescent light and then use a fluorescent filter on the lens to bring the whole area around to normal looking color...

[Stagecoach]

I would also try to establish a white balance using a target like the Whibal Card and either establish a custom white balance or use the target to get close to white balance in PP using Adobe Camera RAW or Lightroom.

I have a small Whibal card that I can use at the the locations although from some trials last night under flourescent lights I found that simply setting a custom WB using a sheet of white A4 was pretty near spot on for my purposes.

In the film days, a common practice was to gel the flash with a green gel to mimic the fluorescent light and then use a fluorescent filter on the lens to bring the whole area around to normal looking color...

I have trialled the green filter that came with the flash but was getting a green hue that remained over a fairly large Kelvin value. Suspect some more trialling is needed but I'm coming to the conclusion that my bounced flash at the locations is likely to fully overpower the ceiling flourescents.

[Manfred M]

I have a small Whibal card that I can use at the the locations although from some trials last night under flourescent lights I found that simply setting a custom WB using a sheet of white A4 was pretty near spot on for my purposes.

The only problem I have run into on occasion with using plain paper is that the optical bleaching agents (OBA) can cause white balance issues as light sources with a UV component can have a bit of a blue colour cast. It does depend on the sheet of paper, so if you have some that works, stick with it.

I have trialled the green filter that came with the flash but was getting a green hue that remained over a fairly large Kelvin value. Suspect some more trialling is needed but I'm coming to the conclusion that my bounced flash at the locations is likely to fully overpower the ceiling flourescents.

Overpowering the fluorescents is good. No mixed light (flash / fluorescent) to cause issues.