There's a lot of confusion about how light affects your damage, whether your weapon's attack stat matters and what contributes the most to your light level. Which is why, a redditor named irCuBiC created this guide. He had decrypted 156 data points, 50+ pieces of loot at increasingly low light and a week later, and he have a decent idea how light and damage works in the endgame (for level 40+ content), and some before.
- Your light level does not directly contribute to damage. It does, however, add a penalty if you're below the recommended light. Going into the raid at 295 light will get you a ~15% damage penalty at Oryx, for instance.
- The attack stat on your weapon matters. Each point of attack seems to add ~0.7% damage.
- Each weapon contributes 12% of your light, each armor piece 10% and ghosts, class items and artifacts 8%.
- Daily heroics and Nightfalls have extra damage penalties on top of everything else.
Light level and character level
Most people think that their damage is determined solely by your light level, but this is wrong. Light level only acts as a "gating" mechanism, to penalize you if you try to enter content under-geared. This only seems to apply to 40+ content, as before that it seems to be based entirely on weapon level (but he clarifies that he never focus on endgame though).
He tested this by popping into the beginning of the raid (a convenient source of infinite 280 light acolytes), equipping a 300+ attack weapon and shooting them in the head, while methodically lowering my light level from 300 in increments of 10 down to 280, then in increments of 1 down to 240.
From this he found out that you get no penalty when your light is equal to or above the enemy's recommended light, but when your light starts dropping below the enemy's light level, damage start decreasing in 4 distinct phases of 10 light each. The first 10 light has the steepest drop (a whopping ~2.85% penalty per light level!), then it starts flattening off. You'll note that this is the exact opposite of the IB scaling, which starts off flat, then gets steeper.
This only applies to weapon damage, ability damage IS directly based on your light, but seems to cap out when your light is 80 above the enemy's recommended light.
You can look at the chart below for the full curve (notice how it has 4 distinct linear segments),
or look at this table for some notable values:
The key takeaway from this is that if you, for example, go into the raid at 290, you're going to eat a 28.5% damage penalty at Oryx, which is fairly substantial.
This also means that players who go into the upcoming King's Fall hard mode at 300 light (the lowest recommended) will have a massive 42.5% damage penalty at the 320 sections, so gearing up aggressively will be necessary to even think about getting past the later sections.
As a mote of trivia, you will also incur a penalty if your weapon's attack is more than 100 above the enemy's recommended light, not that this is very relevant for most of you...
As for character level, you do not seem to lose damage for being underleveled in lvl 41 and 42 content, as damage is the same for level 40 missions and the raid. I'm not entirely sure how this will be affected if the level cap is raised.
Attack vs damage results
Following up the "your damage is not determined by your light" revelation, it stands to reason that what determines your damage is your currently equipped weapon's attack value.
Note: For clarification, a weapon's attack only affects damage done by that weapon. So you won't increase the damage of your primary by equipping a stronger secondary, only the damage done by your secondary weapon.
He tested this, also on the raid acolytes, with two Hung Jury SR4, one at 280 and one at 302, one Tuonela SR4 (basically the "stock" version of the Hung Jury SR4, same impact and therefore comparable) at 283, and two The Dealbreaker at 286 and 290. All done with light level above the enemy's to prevent damage penalties, and on the same enemy, which ensures that any damage difference is due to attack alone. Here are the results, keeping in mind that damage numbers are precision hits:
As you can see, increasing the weapon's attack increases damage independently of light. This pattern persists when his light is the same (by compensating for increased attack by dropping some armor light) or if he leave his armor alone and let it vary, as long as my light level stays above the enemy's recommended light.
You'll also see that two guns of different archetypes do very different damage per shot, despite being of similar attack. This is because per-shot damage is also adjusted by the weapon's impact stat, and he also think that the effect of impact is different based on the weapon's type (so a 48 impact auto rifle will have a lower per-shot damage than a 48 impact scout rifle), but he don't have the data to support this statement.
He haven't figured out exactly how much damage increases per attack, but from the little preliminary data he have, it looks like each point of attack adds somewhere in the area of 0.65% to 0.75% damage, but here I also lack the necessary data to tell if this is a linear relationship or not.
Gear contribution to light level
You may have heard light level be referred to as "average light level", or you might even have heard it being referred to as the more accurate term "weighted average", but what hasn't been clear is how much each gear piece contributes. If you cheated and looked at the takeaway section, you already know that you get 12% of your light from each weapon, 10% for each armor piece and 8% from your ghost, artifact and class item. To increase your light by 1, you'll need 8-9 (8.333) extra attack on a weapon, 10 extra defense on an armor piece, or 12-13 (12.5) defense on ghost, artifact or class item.
He got these values from the source code of Tower Ghost, but he have tested it some, and it seems to check out, even including partial light levels.
This means that while each weapon does increase your light more individually, the majority of your light level comes from your armor (weapons total 36% of your light, armor 40%). You are still better off getting a +10 on a weapon than a +10 on a piece of armor, however, for two reasons: +10 attack gives you +1.2 light, and it also increases your damage output.
Hardmode and Nightfall Penalties
During the testing of this, He discovered something that at first nearly compromised my data. His not sure if a lot of people know this, but it seems like hardmode/heroic and nightfall add extra penalties to your damage, as seen in the table below:
These penalties seem to be weapon attack-based to a certain extent, and each works slightly differently. Hardmode/heroic penalty seems to be a straight 5%, but damage seems to cap out once the weapon's attack hits 280 (you can see my 280 Hung Jury has a 5% penalty exactly), which is much like Y1's damage scaling that was weapon attack based with a cap. Nightfall, on the other hand, seems to add a 10% penalty, until you go above a certain point (which looks like it could be 280, which is the nightfall's recommended light), at which point it starts adding extra penalty.
This leads to the slightly bizarre situation where high-attack weapons do more damage in Nightfall than in Daily heroics.
Other points of trivia
This is where he collect other minor discoveries he have made during this research, that don't deserve their own sections or that he don't have enough data to be confident about. This is just going to be a list.
- Damage in Destiny seems to be calculated with precision damage as the basis, which is why all my damage numbers are precision damage, to avoid rounding errors confounding the result. For instance, with scout rifles you have x3 precision damage multiplier, but many times taking bodyDamage*3 gives you a number that is too high, but doing ceiling(precisionDamage/3) always gives you the right number. This means we technically don't have a precision hit bonus, we have a body hit penalty.
- The Cabal seem to be the only enemy species that have discovered helmets, as they give you a penalty to precision damage. This can make for some confusing numbers until you realize this, and eliminate them as test subjects...
- Year 1 content acts weird in terms of damage scaling, it seems like you get a bonus to your damage. An example is a weapon doing 350 damage in a level 25 Y2 mission, and 491 damage in a level 24 Y1 mission.
- Enemies below level 40 have a static recommended light that is level * 5. So a level 28 enemy would be recommended light 140. This doesn't really matter due to the next point, however.
- Missions below level 40 seem to scale your damage based on the weapon's required level (with the exception of exotics, that sometimes are required level 30, but still scale like a level 40), and ignores your light completely.
- Loot rolls from decrypting engrams is directly based on your current light and not your light upon acquisition. He realize this is commonly known, but he see people asking all the time. He used this to roll items that he could use to lower my light sufficiently for testing against early content. He do not know how this affects raid drops, but my suspicion is that raid drop levels are not based on your current light at all, and just randomly drops in the 300-310 range, weighted towards the bottom.
- This is entirely anecdotal, but loot rolls seem to be in a 40-light level range with your current light level in the center, but stops moving upwards when the upper limit hits 300. Rolls also seem to weight towards the center, with rolls in the outer 5 levels on each end much rarer than the middle 10. This means that your loot roll as a 300+ player can still give you light level 260 items, and that your loot roll chances don't change after you hit 280. He had like to restate that this is not proven, but anecdotal and inferred from the fact that he still get items rolling, like, 262 attack as a 300+ player.
As a benevolent Destiny scientist, He of course have data backing my assertions. Some of it's been extracted into tables in this post, but my entire data set (slightly filtered to remove some data that is incomplete) is in this spreadsheet
The relationship between light, level, attack and damage isn't really that complicated, but it's not immediately made obvious by the game either. This has lead to a lot of confusion, with various people asserting rather strongly one way or another how it works.
The ultimate takeaway from this entire post is that if you have the choice between getting an armor piece that is 10 defense better and a weapon that is 10 attack better, the weapon is always the better option. They'll both add (at least) 1 light, which if you're underlighted increases your overall damage, but the increased attack on the weapon will also further increase your damage output.
For more Destiny guides, you can join our facebook community @ facebook.com/webjunkiesblog.
Credits: Guide by irCubiC