The 3 Camera Modes One Wedding Photographer Uses for Every Portrait

Manual mode has a reputation as the serious way to shoot portraits, and plenty of people switch to it the moment they feel comfortable with their camera. Outdoors, with clouds drifting across the sun and subjects walking in and out of shade, that habit can leave you chasing exposure instead of watching your subject.

After roughly 400 weddings, Martin Castein has narrowed his portrait work down to three modes: full manual, manual with auto ISO, and aperture priority paired with auto ISO and a minimum shutter speed. Program and shutter priority don't make the list. Since aperture priority is his default, aperture becomes the choice he makes on every frame, and he ties it to one question: "What is the background for?" If you picked a spot for its lights, color, and mood, shooting wide open on a lens like a 50mm f/1.2 lets the street melt into soft shapes, and a slightly soft far eye or nose tip stops being a concern. That question gives you an actual reason for each aperture, which is more useful than shooting wide open just because the lens allows it. When the background has to tell people you're in London or on a beach, he stops down to around f/2.8 or f/4 on a 24-70mm zoom so the place stays recognizable while still falling off softly behind the couple.

The mode choice rests on a simple idea he lays out early: "ISO gives you headroom in low light, and shutter speed gives you headroom in bright light." On a sunny day, your ISO is probably already sitting between 100 and 400, close to the floor, so it has nowhere left to go. Shutter speed, on the other hand, can climb from 1/500 s to 1/4,000 s without trouble. That's where manual with auto ISO falls apart in daylight: at f/1.2 or f/1.4, the camera slams into ISO 100, the image starts blowing out, and you're back to turning the shutter dial yourself. Aperture priority with auto ISO and a minimum shutter speed flips the logic, letting the camera hold base ISO and push the shutter faster as the light gets brighter. Castein sets his floor at about 1/500 s in the daytime, which is higher than most people expect, because outdoor subjects turn, walk, and laugh.

Most current bodies offer an "auto" option for that minimum shutter speed, and it's usually built around focal length. Nikon's auto ISO sensitivity control, for instance, sets the slowest shutter based on the lens you have mounted, with an adjustment to bias it faster or slower, and Sony and Canon offer similar automatic settings with their own faster and slower tweaks. That logic comes from the old reciprocal rule, which was designed to keep your hands from blurring the shot. It has no idea whether the person in front of you is still or mid-stride. Castein skips the auto setting because shutter speed, more than aperture or ISO, decides whether he gets the picture at all, and he treats in-body stabilization as if it isn't there, since it steadies the camera and does nothing for a subject who moves. You can apply the same thinking anywhere: any automated shutter or stabilization feature solves for camera shake, so subject motion is still your job to manage, whether you shoot portraits, street, or kids at a birthday party.

Once he drops below 1/500 s, his behavior changes in steps. Under 1/200 s, he starts taking more frames. Under 1/125 s, he takes a lot more, and slower than that, he asks people to hold still or, in his words, to "move in slow motion." The setting pays off in noise, too: at an outdoor cafe in open shade, a 1/1,000 s minimum had his ISO at 3,200, and because his subjects were sitting still, lowering it to 1/500 s brought the ISO straight down to 1,600. His low-light wedding habit adds another layer: he shoots bursts of three to five frames at a slow rate of around 5 fps, because pressing the shutter button moves the camera slightly, which often makes the first frame the least sharp. Two questions decide when full manual is the better choice: is the light on your subject changing, and is the scene confusing the meter? If the light on your subject holds steady while the background keeps changing, manual wins, and strong backlight is the classic case for locking exposure on a face and letting the background do whatever it wants.

Night is when he goes back to manual with auto ISO, since ISO has the headroom in the dark, and he warns that many cameras will drop below your minimum shutter speed once auto ISO hits its limit. He stays on matrix metering, and in contrasty light, he sits about 0.7 stops under in aperture priority, because clipped highlights can lose color that Lightroom can't bring back, while lifted shadows only cost a little noise.

Late in the video, Castein shows a dark, flat frame straight out of camera at 0.7 stops under, then the same photo after his edit.