What exactly are the effects of Aiming Down Sights in apex legends?

Scoping, more commonly known as Aiming Down Sights or ADS, gives you the following benefits:

• Significantly tighter spread on all weapons
• Zoom
• More Control for most weapons

However it has trade-offs, in the form of:

• Your mobility is lowered
• Less awareness as you are now focusing on a single direction
• Some Weapons, like SMGs without stabilizers/stocks become a bit wild

If you are using anything other than an SMG, you will hit more if you ADS. Even shotguns benefit greatly with ADS. The Peacekeeper with the choke hop-up, for example, tightens its spread so much it nearly becomes a rifle. Scout and Sniper Rifles pretty much require ADS to be effective. ARs and LMGs can go either way, but they are more effecting when ADS a majority of the time.

If you do not like to use the ADS mechanic, Apex probably isn't for you.

I assume by scoping you mean ADSing, so right-clicking before shooting? Because scope, or no scope, the effects seem to be similar, at least as far as shotguns are concerned (I only tested shotguns).

In case of shotguns the pattern remains the same (triangle for mozambique, 5-star for peacekeeper, 8 shape for EVA-8, two parallel horizontal lines for mastiff), but in ADS is tighter, so you will hit more pellets when shooting at range and you should not ADS in close combat as you're risking missing with all your pellets.

I also distinctly remember Longbow being useless without ADS. It doesn't matter what scope you've got, if you can compensate you will still shoot your target, but if you try to hipfire, it will just shoot in random direction.