Continuous Lighting Daylight Bulb Recommendations

[Ilan]

Hi folks,

I'm looking to shoot recipe videos and for consistent lighting I'd like to use some daylight bulbs. From my research, I've read that I need CFL bulbs around 5000K - 5500K and with a high CRI (90+).

I was wondering if anyone had any recommendations... the lighting kit I am using right now has two light stands with one standard socket in each (I think they're called Edison sockets), so I need two bright bulbs instead of lots of less bright ones.

Any advice would be very much appreciated... perhaps I don't need what I think I need at all?

Thanks!

Ilan

 

[Ilan]

Okay, I looked into some lights and I've found these:
Westcott Fluorescent Lamp - 50 Watts/120 Volts 5500K 0050 B&H
Kino Flo 6.6" 26W Kino KF55 True Match 26S-K55-120 B&H
Lowel 80W 5500K Fluorescent Lamp for FL0-X (120VAC) E1-80 B&H
NEW 4 X 45W CFL 5500K 91 CRI Fluorescent Continuous Pure White Light Bulbs
ALZO 85W CFL Video-Lux® Photo Light Bulb 5600K - 120V - Pack of 4 - Daylight Balanced Pure White Light & 4250 Lumens - Matches Color Temperature of Kino Flo & Osram Bulbs - Compact Fluorescent Bulbs - Amazon.com

How would you choose?

 

[Achaicus]

For just my own viewing I'd go with highest cri, and after that I might go for a mix of the highest ones in the range you have selected. Each bulb uses a combination of phosphors that may not be exactly the same, so putting several different good quality bulbs together would help hide one bulbs failing points. I would consider for mixing bulbs in the 5000k-6000k range to help cover more specific wavelengths.

For those type of bulbs having a reflector is important. If you mount those bulbs in a box just painting the inside of the box white can give you about a 30% increase in light intensity.

This is just what I'd recommend based on my research on fluorescent lighting for planted aquariums on what would maximize plant growth without leaving the tank looking weird due to low cri.

just my two cents...

 

[Ilan]

That's a good idea, thanks. The issue is that my umbrella stand only holds one light bulb. Right now I'm leaning towards the ALZO, but they don't seem to be available in Canada...

 

[Achaicus]

If you will have an audience see your lighting equipment it makes sense to go with what looks professional. If not you could build something like what is seen in this video and hang that temporarily to light your video shoot. Jump to the 7 minute mark for what I'm talking about.
https://www.youtube.com/watch?v=2bK_kfbLN3M#t=421

I've lit a few shots by having a second person hold up my aquarium light. It is what I have on hand that is both bright and nice, good color light.

 

[dennybeall]

I understand 5500Kelvin as the wavelength of the light but what significance is there to the CFI? If you buy a bulb that is rated at 5500K at the hardware store for 9 bucks what's the difference from the forty dollar one at a photo store.

 

[Mike_E]

With a custom white balance you don't have to worry about the temperature so much as you do having a balanced spectrum.

There isn't a whole lot you can do color-wise with a range of 500 kelvin.

You also need to be concerned with consistency. Having set your white balance you don't want your lighting to be wandering all over the place making you spend hours in post trying to stabilize it.

 

[Achaicus]

5500k refers to white ballance of the light so to speak. Lower than that gets more and more red and higher gets bluer. But this is just a generalization and does not tell the whole story. I think, dennybeall, you are asking what color rendering index (CRI) means. This is a measure of how close the light from the bulb gets towards making colors appear as they do under sunlight. Individual phosphors in fluorescent bulbs have thin lines of output at specific wavelengths if viewed on a spectrometer and have to be combined to get a good color balance. The specific phosphors used in each bulb varies, so even two bulbs of the same 5500k may have widely differing light quality. Usually 3 main phosphors are used and others may be added to get better quality light, but that could make them cost more.

I think more goes into making a phosphor mix for a bulb that has a good color rendering index (CRI) whether it is a tube or a compact fluorescent light (CFL) and that would tend to cost more. That photo store bulb may cost more than the hardware store one even without the photo store markup done because it is a niche application and the evaluation of it's suitability has already been done.

 

[KmH]

I understand 5500Kelvin as the wavelength of the light . . .

The Kelvin number is a color temperature, not the wavelength (frequency) of the light.

Zero K on the Kelvin temperature scale (-273.15°C/-459.67 °F) is absolute zero, or the point where thermal motion ceases.