  Electron and photon triggers covering transverse energies from 5 GeV to
several TeV are essential for signal selection in a wide variety of ATLAS
physics analyses to study Standard Model processes and to search for new
phenomena. Final states including leptons and photons had, for example, an
important role in the discovery and measurement of the Higgs particle.
Dedicated triggers are also used to collect data for calibration, efficiency
and fake rate measurements. The ATLAS trigger system is divided in a
hardware-based (Level 1) and a software based High-Level Trigger (HLT), both of
which were upgraded during the long shutdown of the LHC in preparation for data
taking in 2015. The increasing luminosity and more challenging pile-up
conditions as well as the higher center-of-mass energy demanded the
optimisation of the trigger selections at each level, to control the rates and
keep efficiencies high. To improve the performance, multivariate analysis
techniques were introduced at the HLT. The evolution of the ATLAS electron and
photon triggers and their performance is presented, including initial results
from the early days of the LHC Run 2 operation.
