Feather Field 2014

1st-level abjuration

Casting time: 1 reaction, which you take when you are targeted by a ranged attack from a magic weapon but before the attack roll is made
Range: Self
Components: V, S, M (fletching from an arrow)
Duration: 1 round

A magical barrier of chaff in the form of feathers appears and protects you. Until the start of your next turn, you have a +5 bonus to AC against ranged attacks by magic weapons.

At higher levels

When you cast feather field using a spell slot of 2nd level or higher, the duration is increased by 1 round for each slot level above 1st.

Slot	Duration
2nd	2 rounds
3rd	3 rounds
4th	4 rounds
5th	5 rounds
6th	6 rounds
7th	7 rounds
8th	8 rounds
9th	9 rounds

Source: Deep Magic for 5th Edition (Kobold Press) · License: OPEN GAME LICENSE Version 1.0a details