Manual exposure with auto ISO is the most practical exposure mode that most photographers leave unused. The RF 35mm f/1.8 IS Macro STM — Canon’s modest, versatile nifty-enough-fifty-equivalent for the R system — is the lens where this mode earns its keep, because the lens covers such a wide range of use cases in a single shooting session that fixed manual settings cannot follow it. The setup: set the camera to M mode, ISO to Auto, aperture to whatever the scene requires (f/4 for general use with context in the background, f/1.

Back-button focus separates autofocus activation from shutter release. The shutter half-press no longer engages AF. Instead, the AF-ON button on the rear of the camera acquires and holds focus. It is the single camera configuration change that most noticeably improves shooting consistency, and the RF 24-105mm f/4L IS USM — the kit lens for most R5 and R6 kits — is where most photographers should learn it. The mechanics: hold AF-ON to focus continuously on a moving subject.

Shooting directly into a light source is the fastest way to ruin a technically correct photograph and the slowest way to make a memorable one. The RF 50mm f/1.2L USM handles the contradiction better than it has any right to. The technique is contre-jour — French for “against the day,” meaning your subject is between you and the primary light source. The light halos the subject, separates them from the background, and collapses foreground detail into silhouette or near-silhouette.

Dual Pixel RAW is a Canon capture mode that records each pixel’s left and right photodiode data separately, storing approximately twice the file size of a standard RAW. The primary advertised use — bokeh shift, ghost reduction — is marginal in most practical situations. The genuinely useful application is microadjustment of the focus point in Canon’s Digital Photo Professional software after capture. At f/1.2 on the RF 50mm, the depth of field is thin enough that a focus acquisition that lands two millimeters in front of the intended plane produces a noticeably soft result.

The R5 Mark II’s electronic shutter reaches 1/64000s. In practice, 1/8000s is the useful ceiling for most fast-motion subjects — athletes, birds in flight, children running — because beyond that shutter speed, the light gathering falls off steeply and ISO requirements climb into ranges where noise management becomes the dominant concern. At 1/8000s with the RF 85mm f/1.2L and ISO 1600 in full sun, you get a completely motion-frozen frame. A sprinter at 10 m/s travels 1.

Expose to the right — ETTR — is the practice of increasing exposure until the histogram is as far right as possible without clipping important highlights. It exploits the mathematical distribution of data in a RAW file: in a 14-bit file, the brightest stop of light receives half of all the available tonal values. Underexposing by one stop discards half the sensor’s information into the shadow region, where noise lives.

At f/1.2, the depth of field on an 85mm lens is approximately 2.5 centimeters at typical portrait distance. That is the width of a human eye. Focus must land on the near eye, precisely, every frame. The reason to own an RF 85mm f/1.2L DS is the RF 85mm f/1.2L DS — and the reason it is usable wide open is Eye AF on the R5 Mark II or R6 Mark II.

The old instruction — f/8 and be there — predates autofocus and has survived it intact. The RF 28mm f/2.8 STM is the current Canon lens that most efficiently implements this philosophy. Small, sharp, negligible weight, and optically honest without aspiring to be a collector’s item. It is a working lens. At f/8 on a full-frame sensor, the 28mm focal length delivers a depth of field that runs from roughly two meters to the horizon when focused at five to six meters.

Focus breathing is the change in angle of view that occurs when a lens is racked from one focus distance to another. As a lens focuses closer, many optical designs shift internally in ways that alter the effective focal length — the image either zooms in or pulls back as focus changes. For still photography, this is invisible. For video, where focus pulls are a standard part of camera movement, breathing is a visible artefact that marks the moment the operator changed focus.

Focus peaking is an EVF overlay that highlights in-focus edges in a selected color — typically red, yellow, or white — as you rotate the focus ring. It is a mirrorless-native feature, unavailable on optical viewfinders by definition, and it changes the character of manual focus work on modern cameras in ways that make the technique accessible where it was previously a specialist skill. The RF 35mm f/1.8 IS Macro STM has a smooth, well-damped manual focus ring with enough rotation travel to be used precisely.

The Canon R5 Mark II’s IBIS combined with the RF 15-35mm f/2.8L IS USM provides up to eight stops of combined stabilization according to Canon’s specification. In practice, on a full-frame sensor at 15mm, that means a stationary subject can be photographed sharp handheld at shutter speeds as slow as 1/4 second by a photographer who has learned to hold still. This is not theoretical. It works. The technique is breath control and body mechanics.

The RF 100-500mm f/4.5-7.1L IS USM is Canon’s accessible super-telephoto — L-series quality, manageable weight at 1.37 kilograms, and a zoom range that covers most wildlife and sports scenarios without a second body. The technique that makes it earn that range is not the zoom itself. It is pre-focus combined with burst discipline. Pre-focus means acquiring focus on a known point before the decisive moment, then holding it. A bird banking toward a perch, a runner coming through a gate, a vehicle entering a corner — the trajectory is predictable.

Evaluative metering is correct most of the time. It analyzes the scene, weights the meter reading toward the focus point, and produces an exposure that protects the most information across the widest area of the frame. In scenes with even illumination and a subject that occupies a significant portion of the frame, it works without adjustment. In scenes where the subject is lit differently from the background — a face in open shade against a bright street, a person near a window with an unlit room behind them — evaluative metering averages toward a wrong answer.

A sunstar is not a filter effect. It is a diffraction phenomenon produced by the aperture blades of the lens when a point light source — the sun, a street lamp, a bare bulb — is included in the frame. The RF 14-35mm f/4L IS USM produces it cleanly. The technique is to use it intentionally rather than stumble into it. The mechanics: at wide apertures, light bends minimally around the aperture blades.

Every lens on every sensor has a diffraction limit — the aperture beyond which stopping down no longer increases sharpness but instead decreases it. Light diffracts around the aperture blades, spreading the point spread function across adjacent pixels. On a high-resolution sensor like the R5’s 45-megapixel chip, diffraction becomes measurable at around f/11 and visible at f/16. By f/22, you have traded resolution for depth of field at a poor exchange rate.

The RF 50mm f/1.2L USM vignettes at f/1.2. This is not a defect to correct in post. Left uncorrected, it is a compositional tool that draws the eye toward the center of the frame and applies a graduated darkening to the corners. Canon’s in-camera lens correction and Lightroom’s lens profile will eliminate this automatically if you let them. You should consider not letting them. Optical vignetting at the maximum aperture of a large-diameter lens is a physical consequence of the geometry: light arriving at the sensor from the edges at oblique angles is partially blocked by the lens barrel.