The plural of photographer is photographers.
The reason is because the word is derived from Ancient Greek. For Greek words ending in a f remains the f also stand in plural.
Photographer comes from the Greek word φωτογράφος (fotográfos). The word photographer means "Those who write with light"
- Light, φως (fós)
- Writing, γράφω (grápso)
The term was coined in the early 19th century to describe someone who takes photographs, which are images captured by recording light on a light-sensitive medium such as film or a digital sensor.
How a photographer writes with light:
A photographer writes with light using existing light or flash. In doing so, the photographer adjust the light sensitivity of the negative or sensor. The throughput of light can be limited by the aperture and the duration of light can be determined by the shutter.