Answer: Polarization
Step-by-step explanation:
Probably what happens here is that Derek took his photograph with a polarizing filter (which is helpful to avoid that glare from the surface of water, for example), and Wes took his without that filter.
It is important to note, this kind of filter works with an optical phenomenon called polarization, which consists in the alignment of light (electromagnetic waves) in only one vibrational orientation.
To understand it better:
Normally, electromagnetic waves are not polarized, and the vibration occurs in all planes. However, if we make these waves to vibrate in a single plane, we have polarized light.
This is only possible because electromagnetic waves are transversal waves, hence the oscillation occurs in the transversal direction to the propagation.
Note this is not possible for longitudinal waves (sound), because the oscillation occurs in the same direction as the propagation.