A simple way to think about it.
MCD and viewing angle are VERY related.
Like a Mini-MagLight with the removable front lens and reflector.
Go out after dark, 100' from your house.
Focus the beam as tight as it will go. Shine it on the house. Quite bright. High MCDs.
Focus it wider. Shine it on the house. Not as bright. Less MCDs.
Remove the reflector. Shine it on the house. Very dim. Very low MCDs.
Same bulb and batteries, so the lumens (total light) is the same.
Just depends on how it is spread out.
The MCDs (intensity) changed.
A laser has great MCDs, but it is useless as a flashlight or area light.
The viewing angle is usually listed at "2 theta half degrees", meaning half the total light falls in a circle that many degrees.
A really bright sounding LED with a viewing angle of 10' is probably not so bright.
(Start Rant)
And many (most?) No-Name LEDs are very over rated. In MCDs and viewing angle.
Often an entire production lot will not have a single LED meeting the rated specs.
I even had a sample batch with 20% having the polarity reversed!
Don't even get me started on color ratings! Had a sample batch that I thought they actually sent blue instead of white, but was basically informed "What do you expect for that kind of price?" And the price wasn't very good.
The high wattage type, like 1/2, 1, and 3 watt, are LESS efficient than a decent incandescent bulb. A waste of money and power, except in very limited applications.
(End Rant)
So it depends on what you want to do with them. 20' is nice in a flashlight. 60' is nice for an area light. Name Brand stuff is better.
G-
