LED nerds. Any help with Lumens? How are they measured?

[frascati]

.

I just received some SORAA MR16 bulbs in the mail.
SM16-09-25D-830-H1
I paid a premium price for these based on the 725LM @ 25 degree brightness.
The specification sheet at SORAA and the specifications listed at the distributor that I purchased them from confirm this rating.
However when the bulbs arrived, the sealed OEM packaging lists the correct bulb, SM16-09-25D-830-H1, and the bulbs
within the packages confirmed as the correct bulbs...
But the package specs say "90 degree Lumens: 685LM.
https://pasteboard.co/Jd74vbd.jpg

Is this correct?

 

[StarHalo]

You need at least a 10% difference in output before you can discern any difference by the eye, so a 685 and 725 lumen emitter side-by-side would appear identical.

 

[frascati]

 

[StarHalo]

I can always discern Millie and her dog :thumbsup:

 

[Whitelight1]

Lumens are measured with an integrating sphere.

 

[bykfixer]

I've always wondered why there isn't an LED model thread like there is a light bulb type thread here.

 

[frascati]

I can always discern Millie and her dog :thumbsup:

My favorite easy-to-find beer. Usually stocked at Meijer's grocery and Walmart in my area.
I spotted the little sumpin right away

 

[frascati]

What I was hoping someone might clarify for me, enLIGHTEN me on, was the significance of beam spread, degree, in the lumens rating. Is it significant?
725Lm at 25 degrees. 685Lm at 90 degrees? This might explain the difference in Lm rating on the bulb, if true.

Did the pasteboard image link open for you? My work computer is URL filtered and won't show it.

And sorry for the bad pun...

 

[StarHalo]

What I was hoping someone might clarify for me, enLIGHTEN me on, was the significance of beam spread, degree, in the lumens rating. Is it significant?
725Lm at 25 degrees. 685Lm at 90 degrees? This might explain the difference in Lm rating on the bulb, if true.

I'm not previously aware of the use of a degree rating to measure lumens; typically if you account for the beam shape of the emitter, it's to express in lux/cp what the throw of the beam is, not the output. Otherwise, if you're going to provide a lumen rating, especially for a bare emitter, it needs to be a gross overall lumens number not muddled by how the light is projected.

 

[frascati]

I'm not previously aware of the use of a degree rating to measure lumens; typically if you account for the beam shape of the emitter, it's to express in lux/cp what the throw of the beam is, not the output. Otherwise, if you're going to provide a lumen rating, especially for a bare emitter, it needs to be a gross overall lumens number not muddled by how the light is projected.

"..especially for a bare emitter..."
Except that the MR16 is not a bare emitter... if I understand the terminology correctly.
This is an image of the Soraa Mr16.

It's a 'bare emitter' housed in a 25degree spot reflector.
The .pdf spec sheet from Soraa lists it as follows..

3000K		Halogen Equivalent	Watts	Beam	Lumens	CBCP	Model #

Brilliant HL 9W CRI 90 R9 50 Indoor/Outdoor

75

9

25

725

3730

SM16-09-25D-830-H1

08738

And this is the packaging the bulb arrived in.
https://pasteboard.co/Jd74vbd.jpg

It's actually a pretty damn amazing little bulb. 700(approx) lumens 25 degree spot with great color rendering. 9watts/12vac. I'm using a pair of them
leading the way through the night on 1984 Puch moped. The magneto puts out 3 to 18vac with just enough wattage to light them fully. They handle
the ragged voltage and current spikes from the ancient magneto superbly. I've had a less bright pair of these MR16s, philips brand, on my three mopeds
for 10 years now without fail and no noticeable loss of brightness.