Where are the shortcut keys for Canon eosr metering mode?

First, turn on the Canon camera and press the shutter to measure light, then adjust the corresponding aperture and shutter value as needed, and then press and hold the "*" key on the fuselage to lock the exposure (the * icon lights up to indicate the exposure lock).

The full name of SLR is single-lens reflective viewfinder camera, which refers to a camera where light shines on the reflector through a single lens and views through reflection. The so-called "single lens" means that the photographic exposure light path and the framing light path * * * use one lens, unlike the paraxial camera or the double-reflex camera, the framing light path has an independent lens.