I am aware that some of this information has been posted before but it is still very relevant. I also included some extra information.
In Destiny we have two different Orb sizes. We call them small and large Orbs. You need about 12 small Orbs to completely fill your super (from 0 to 100%). And if you pick up about 6 large Orbs your super will be charged. Also large Orbs makes 100% more super energy than the small ones.
So clearly large Orbs are much better than small Orbs, but what determines which Orbs you will make?
Small Orbs are produced if you fill the last percents of your super with Orbs.
In fact it is very easy to make large Orbs. The rule is to not fill the last segments of your super bar with Orbs. So in theory you can fill 99% of your super with Orbs while the last percent is filled by either waiting or killing enemies. If you do this you will make large Orbs for your teammates which is awesome.
We also have some artifacts, weapons and perks that produce different Orb sizes:
Artifact perks: Artifact perks will always produce large Orbs, for example the artifact perk Fallen Piercer (if you kill a fallen with a precision shot) will make a large Orb.
Telesto (the besto): Sadly Telesto will only make small Orbs.
Defender perk Gift of Light: Always large Orbs.
Sunsinger perk Sunburst: Just small orbs.
Needs to be tested:
Bolt-Caster perk Live by the Sword:
Vault of Glass Helmets: Thanks to /u/WolfheartSed .
Defender perk Gift of the Void:
Defender perk Iron Harvest: Thanks to /u/PutinPudding
If there are anything that produce Orbs of Light that I forgot please let me know and I will test it.
tl;dr: There are two different Orb sizes in Destiny, small and large Orbs. 6 large Orbs will fill your super while 12 small Orbs will do the same. If you have filled the last part of your super bar with Orbs you will make small Orbs. If you have filled the last part your super bar by killing enemies and waiting you will make large Orbs.
EDIT 2: Added several things that needs to be tested.
EDIT 3: Realized I messed up, Gift of Light will always make large Orbs. I have yet to figure out which Orb size Gift of the Void makes.