eF

EF is an initialism used to denote several different concepts across domains. The most common references include those in technology, education, computing, psychology, and environmental science.

Canon EF lens mount: The Canon EF (Electro-Focus) lens mount was introduced in 1987 for Canon’s 35 mm SLRs, enabling fully electronic autofocus and communication between camera bodies and lenses. It is the standard mount for the Canon EOS system and has spawned variants such as EF-S for crop-sensor bodies and the newer RF mount used on mirrorless cameras.

EF Education First: EF Education First is a private education company founded in 1965 that offers language training, study abroad programs, cultural exchange, and educational travel experiences. The organization operates worldwide and also provides services for schools and corporate clients.

Entity Framework: In software development, Entity Framework (EF) is Microsoft’s object-relational mapper for the .NET platform. It enables developers to work with data using .NET objects, abstracting database access. EF Core is a cross-platform rewrite that supports modern data access patterns and multiple database providers.

Executive function: In psychology and neuroscience, executive function (EF) refers to higher-order cognitive processes that regulate goal-directed behavior, including planning, working memory, cognitive flexibility, and inhibitory control. These functions are critical for tasks such as problem solving and adapting to new situations.

Emission factor: In environmental science and life-cycle assessment, an emission factor (EF) quantifies emissions per unit of activity or production, used to estimate greenhouse gas outputs, pollutants, or energy use in inventories and reports.

Fermi energy (E_F): In solid-state physics, E_F denotes the Fermi energy, the highest occupied energy level at absolute zero in a system of fermions, such as electrons in a metal. It is a key parameter in describing electronic properties.