Full Manual Exposure
Every camera has an automatic mode, and for good reason - it works well most of the time. But auto mode doesn't know what your photo is supposed to feel like, and shutter speed and ISO are two of the most direct tools for making it feel the way you intend. Mark III gives you full control over both.
The four exposure modes
The exposure mode picker sits in the upper right of the viewfinder. Tap it to cycle through all four modes.
Shutter speed: freezing and blurring motion
Shutter speed controls how long the sensor is exposed to light. A fast shutter (1/1000s or above) freezes motion completely. A slow shutter (1/30s or below) lets motion blur across the frame. It's a creative choice, so there is no wrong answer.
The practical thing to know: in low light, a slow shutter lets in more light, but anything moving in the frame will blur. If you're handholding, anything slower than about 1/60s will also start to show camera shake. Shutter priority is the most direct way to take control of this tradeoff.
ISO: sensitivity and grain
ISO controls how sensitive the sensor is to light. Low ISO (100-400) produces a clean image with minimal grain. High ISO (1600 and above) lets you shoot in very low light, but introduces more grain and reduces color accuracy. With Halide's film simulation, some of that grain can actually work in your favor.
The exposure meter
This is one of our favourite additions to Mark III that is only available in the minimal theme mode. When you're in any manual mode, a classic analog-style exposure meter appears in the upper left of the viewfinder. The needle shows you whether the current settings will produce an underexposed, overexposed, or correctly exposed shot.
This matters because the iOS live viewfinder doesn't always accurately reflect what the sensor will actually capture when you press the shutter button. It uses some computational processing that can make the preview look different from the final image. The exposure meter reads directly from the sensor, the same way a light meter on a film camera does. It's a reliable read on the actual exposure, independent of how the preview looks.
A starting point for manual shooting
If full manual feels overwhelming at first, start with shutter priority. Pick a shutter speed that suits your subject. Use a fast speed for anything moving or a slower speed for static scenes in low light, and let the camera handle ISO. Once that feels natural, try locking ISO too and reading the exposure meter to make the final call yourself. That's the full loop of manual photography, and it gets intuitive quickly.
Lesson 9: We'll recap the full Mark III workflow and introduce one more feature worth knowing about.