Comparing Different Light Sources in Photos

Stress_Test

Flashlight Enthusiast
Joined
Feb 18, 2008
Messages
1,334
A while back, I posted some images in another thread comparing a couple of LED and incan lights I had. I figured I'd do a broader set of images this time, and include a few more hi-cri LED lights as well. I especially wanted to see how my newest hi-cri light looks.

As I posted in Ampdude's thread, there's a hefty disclaimer here (this text is pasted from what I wrote there):

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it's hard to make such comparisons when the lights are different color temp (Kelvin) values, and also vastly different beam profiles. Some of the lights are throwers so I had to do the light-painting thing to try to hit the subject evenly.

It does make it harder to compare different lights if the target in the photo isn't being lit the same way, but I don't know any way around that other than just using the bare emitter with no reflector/optic. And no lens either, since the AR coating can introduce tints as well. And even THEN, some lighting relies on the optics to mix out the color gradient of the LED (to avoid a yellowish corona for example), so... yeah. Any comparo like this has to be taken with a grain of salt.

This does let me find out if there's a particular light that I definitely do NOT want to use for photos; some of mine have pretty strong tints, mainly green. That can be corrected in post-processing but it adds more work.
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All that said, here are the images, in no particular order. I set the camera white balance to try to split the difference between all the lights; the K value is the same for all images. ISO stayed the same, but I had to adjust aperture and shutter speed in some cases where I had to do light-painting (see above).

I tried picking a few items for a target that would represent a decent range of color, and I think the softer pastel colors on the LOTR book art also make a good subject.

Can you tell which images were lit by LED, and which were lit by incan? After allowing some time for guesses, I'll say which image corresponds to what light source (the #s shown are my file #s so I can keep them straight)

#326
KRKJ061.jpg

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#327
79kT93d.jpg

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#328
hSCxNW9.jpg

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#329
MyfdU4I.jpg

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#332
LLDP7uw.jpg

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#333
3GZw9mw.jpg

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#335
ZnNasDj.jpg
 

NH Lumens

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Joined
Dec 14, 2014
Messages
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EDCLB.com
I wonder why lower lumen but focused lights are brighter than comparable higher lumen lights?

Lumens are not the measure of brightness - candela (cd) is.

Lumens, or luminous flux, is the total amount of light the flashlight can produce. This amount of light (measured in lumens) is distributed across the entire beam.
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Candela, or luminous intensity, is how the lumens are focused, and how bright the beam appears as a point source. The more focused the lumens are, the higher the candela and the brighter the beam appears at distance.

A 500 lumen / 35,000 cd flashlight is over 6x brighter than one rated at 1,200 lumens / 5,500 cd).

In the diagram below;

Luminous flux - lumens
Luminous intensity = candela
Illuminance = lux (at one meter, lux and candela are the same nubmer)


nance-illuminance-luminous-intensity-luminous-flux.png
 
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