Newly used LED lighting

[chauncey]

Trying out LED lights...color temp seems to be about 2700 kelvin using Color Checker Passbook.
What say you about the colors of the artificial flowers?

[DanK]

Interesting. They look reasonable, but it is hard to say, given that we don't know what the flowers should look like. One thing I have read about LEDs is that it's not just a matter of color temperature, but also that many have an unnatural distribution of colors. E.g., I have often read about a "magenta spike." If there are newer LEDs without these problems, I would be interested in trying them out instead of the halogens I now use for ambient lighting.

[Mark von Kanel]

Hi, WM.

very hard to say, the light is to uneven to asses and there's nothing to compare it against, you have under and over exposure so its hard to tell what they should look like, if you could re shoot with more even lighting and give us a daylight shot comparison, we might be able give you an opinion.

at the end of the day if your using colour checker to compensate for cast, as long as the spectrum is constant, will it matter? (question not statement)

[ajohnw]

Illuminating via LED's is a bit hit and miss. They emit 3 colours usually but there are some that use 4. The fact that they don't emit a continuous spectrum can have all sorts of effects on reflected colouration..

John
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[chauncey]

One thing that I did become more aware of...converting to RGB/sRGB from ProPhoto tends to boost
exposure between 5-10%. Heed the clipping/don't ETTR as much as I have been.

[Mark von Kanel]

Illuminating via LED's is a bit hit and miss. They emit 3 colours usually but there are some that use 4. The fact that they don't emit a continuous spectrum can have all sorts of effects on reflected colouration..

John
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Not much use for togging then?

[Peeshan]

It somewhat reminds me of old film commercial photography. Especially the right-half. That can be useful to keep in mind if one wants to recreate this kind of feeling.

[ajohnw]

Not much use for togging then?

People do use them for illumination but perhaps it's easier to describe how they work rather than give instances where there will be problems. The blue they emit tends to be well down to near UV and our eyes aren't very sensitive to it so if you take a warm white type the blue light outputted is more or less the same as the level of green. A lot higher on daylight types. Power led's use this blue to cause phosphors to fluoresce at the other colours they emit. The blue has been called dental blue - same sort that is used to cure fillings or at least very close to it.

It doesn't surprise me that wm had an odd colour temperature reading due to the wavelength of the blue. As we aren't very sensitive to it the filters in cameras etc probably cut it down rather a lot and can't really measure it. Who knows what some surface will make of it when it's reflected.

Must admit I am not very keen on them having had the blue interfere with my colour vision by looking directly at the the light they emit. I used them for microscope illumination. A lot of people do as it gives a sort of constant colour temperature for photography what ever light levels are set unlike bulbs. What can and does happen in my case is that the blue receptors get over loaded and retain the blue for some time.

I'm a little glad that so far displays appear to make no use of similar wavelengths of light. This restricts the gamut but once bitten twice shy.

Some sources reckon there is a murphy's aspect to the anthropic principle to the blue as well. It coincides with a region where there is a dip in the sensitivity of our eyes. Sound's like we are better off not seeing it.

John
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[Shadowman]

Well done, colors look fine.

[Mike Buckley]

Why not use compact fluorescent bulbs rated at 5500K? What's the attraction of using LEDs?

[AB26]

William,

To me it looks fine.

Thanks for posting this. After reading the comments I think I will do a few tests with an LED flashlight (torch). The results may be interesting.

The 2700K does not sound right to me. LED is supposed to be white light?

Well you gave me something to do tonight. Thanks.

[ajohnw]

William,

To me it looks fine.

Thanks for posting this. After reading the comments I think I will do a few tests with an LED flashlight (torch). The results may be interesting.

The 2700K does not sound right to me. LED is supposed to be white light?

Well you gave me something to do tonight. Thanks.

Well I suppose that I could have included that they produce white via a mix of red green and blue and that colour measuring devices that use r g b measurements assume wavelengths.

John
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[AB26]

What's the attraction of using LEDs?

Mike,

How does this sound:
Fenix TK40
630 Lumens for 2 hours with 8 AA batteries.

[Mike Buckley]

2 hours with 8 AA batteries.

For studio work such as was used to make the photo in the thread, why not simply plug the lamp with a compact fluorescent bulb into the wall and forget about the batteries? I still don't understand the attraction of LED lights.

[AB26]

a compact fluorescent bulb

Emitting 630 lumens? I don't think so.

[Mark von Kanel]

Emitting 630 lumens? I don't think so.

£126 for a torch? expensive lumens!!

the cfl below £1.49 for 600 lumens....

View Large Image

• 

Philips 11W BC Genie CFL Stick Bulb

Product Code: 190902

• Pack Quantity: 1 Pk.
• Lumens: 600 lm
• Equivalent Wattage: 50 W
• Actual Wattage: 11 W
• Average Life Span: 10000 hours
• Bulb Fitting: Bayonet Cap (BC)
• Bulb Fitting Specification: B22
• Bulb Shape: Stick
• Colour: Warm White
• Features: Non-Dimmable-Rapid Start
• Energy Efficiency Rating: A
• Brand Name: Philips

Good light quality in a compact shape

i know wher my money will go

[ajohnw]

£126 for a torch? expensive lumens!!

the cfl below £1.49 for 600 lumens....

View Large Image

• 

Philips 11W BC Genie CFL Stick Bulb

Product Code: 190902

• Pack Quantity: 1 Pk.
• Lumens: 600 lm
• Equivalent Wattage: 50 W
• Actual Wattage: 11 W
• Average Life Span: 10000 hours
• Bulb Fitting: Bayonet Cap (BC)
• Bulb Fitting Specification: B22
• Bulb Shape: Stick
• Colour: Warm White
• Features: Non-Dimmable-Rapid Start
• Energy Efficiency Rating: A
• Brand Name: Philips

Good light quality in a compact shape

i know wher my money will go

You should be looking for something like this

http://www.ebay.co.uk/itm/105W-eq-52...item54068f0f7c

But ideally with a better cri rating.

John
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[Mike Buckley]

Emitting 630 lumens? I don't think so.

Charts I've seen explain that a typical compact fluorescent bulb of 20 to 30 actual watts will generate about 60 lumens per watt. Bulbs with lower wattage generate 40 to 50 lumens per watt. I'm using 30-watt bulbs, so that's about 1800 lumens.

[Mark von Kanel]

You should be looking for something like this

http://www.ebay.co.uk/itm/105W-eq-52...item54068f0f7c

But ideally with a better cri rating.

John
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LOL gotta get me some of those!

[chauncey]

You guys are doing nothing but confusing me.

I took two images, one using a CF 2700 Kelvin 100 watt bulb, the other a LED 4700 Kelvin 100 watt bulb.
The base image is the CF bulb, while the belts are the LED bulb.



Was interesting in that although they were both rated at 100 watt, the CF needed a 2/3 stop slower SS.
Which is better...you choose.