The [‘r] sound
The sound the alphabet letter [R] makes by itself is the same sound found in:
hurt vs heart
The Schwa is the sound an unstressed vowel makes. It sounds similar to the [uh] which is the sound of the short ‘u’, only your mouth is less open.
Note: with the word ‘photography’, the second ‘o’ is the stressed vowel, and the other vowels are unstressed.