Light first, frame second — the camera comes last.

The hour after sunrise and the hour before sunset are worth an alarm. With the sun low, its light travels through far more atmosphere, which scatters the short blue wavelengths away and leaves the warm ones — and it arrives from the side, so everything grows a long shadow and texture stands up off the ground. It also changes quickly: fifteen minutes before sunset and fifteen minutes after are two different pictures, so arrive early and stay late. The blue hour that follows is dimmer, cooler and very even, which suits water and towns as the lights come on.

Overcast is not bad light. A cloud layer is a softbox the size of the sky: it turns one small, hard source into an enormous diffuse one, so shadow edges go soft, the brightness range drops to something a sensor holds comfortably, and colour reads deeper because there is less white glare bouncing off every wet leaf. The catch is the sky itself, which renders as a flat white hole — keep it out of the frame, or use it on purpose as empty space.

Indoors, one window does most of the work. A window that never takes direct sun gives a steady, soft source for hours. Distance is both the dimmer and the contrast control: close to the glass the light falls away sharply across the subject, which is dramatic; two steps back and it flattens and evens out. A sheet of white card on the shadow side fills the dark half with no extra hardware at all.

Midday is the hard case. Overhead and undiffused, the sun makes short, sharp shadows, hides eyes under brows, and often spans a wider range than the sensor can record, so you end up choosing which end to lose. Treat it as a graphic light — chase shadows, patterns and strong shapes — or step into open shade under a wall or a canopy and let the whole sky become the source instead.

A stop is one doubling or halving of light. That is the whole trick: all three controls move in the same currency, so a stop given up by one can be taken back by another and the picture keeps the same brightness. What changes is the side effects, and choosing which side effect you want is most of photography.

Aperture is the size of the opening, written as an f-number — focal length divided by the diameter of the opening, which is why the numbers run backwards and f/2 is much wider than f/11. The full-stop series steps by a factor of about 1.41 each time, which halves the area and so halves the light. Open up for light and a shallower plane of focus; close down for depth of field, though past roughly f/11 diffraction begins to soften fine detail.

Shutter speed is simply how long the sensor is exposed, and it trades against movement of two kinds. A rough handheld floor is one over the focal length — about 1/50 s on a 50 mm lens — and stabilisation buys a few stops back, but nothing except a short exposure freezes a subject that is moving itself. Long exposures are a choice rather than a failure: water and cloud smooth into something the eye never sees.

ISO is amplification applied after the light is collected, so raising it never gathers one extra photon. It brightens a thinner signal, and noise and lost highlight headroom come along with it. Sensors are good enough now that a slightly noisy sharp frame beats a clean blurred one — pick the ISO that lets the other two settings be what the picture actually needs.

• f/1.4
• f/2
• f/2.8
• f/4
• f/5.6
• f/8
• f/11
• f/16
• f/22

Full stops. Each step to the right halves the light reaching the sensor.

None of this is a rule. They are habits — things worth doing every time until they stop needing thought, so the attention is free for the light.

• Take the thirds as a bias, not a law. Divide the frame in three each way and hang the horizon or the subject near one of those lines; the picture then has somewhere to breathe. Dead centre is not forbidden, it is a decision, and it is the right one when the scene is symmetrical or the subject is staring straight back at you.
• Follow the lines already there. Paths, fences, shorelines, kerbs, long shadows: the eye runs along them whether you planned it or not. Send them from a corner towards the subject and the picture has a route through it. Diagonals read as movement; flat horizontals settle everything down.
• Read the edges before you press. Run your eye around the whole border every time. Corners collect rubbish — a blown patch of sky, a stray branch, half a sign, a hand cut off at the wrist. The fix is one step to the left now, or lost pixels in a crop later.
• Separate the subject from the mess behind it. Three ways to do it: a longer lens and a wider aperture to throw the background out of focus, a difference in tone so a light subject sits against a dark ground, or simply empty space around it. Backgrounds do not improve on their own while you wait.
• Move your feet. Where you stand changes the relationship between everything in the frame; zooming only changes how much of it fits. Crouch to put a foreground in, climb a step to separate a horizon, walk three metres closer. Most of the improvement in a picture comes from this and costs nothing.

The aim is a file that looks like the thing you stood in front of, finished in a few minutes. A fixed order helps, because it stops you polishing a frame you were never going to keep.

1. Cull first, and quickly. Two passes: flag anything worth a second look, then from each scene keep the single frame that is sharpest and best timed. Editing pictures you would not have kept is the main way an evening disappears.
2. Straighten, then crop. Level the horizon on the water line rather than the shoreline, and get the verticals upright. Crop to the composition you meant, accepting that a large crop costs real resolution.
3. Fix exposure and white balance globally. Small moves only: pull back blown highlights, lift the shadows a little, and set white balance to the way the scene felt rather than to neutral grey — golden hour is supposed to be warm, and correcting that away throws out the reason you were there.
4. Do local work last and keep it small. A gentle dodge to hold an eye, a burn to quieten a bright corner, nothing that draws attention to itself.
5. Stop before it looks unreal. The tells are consistent: pale halos along skylines from too much clarity or sharpening, blacks blocked up with no detail left in them, and skies so saturated the gradient has banded. Toggle back to the untouched file, then look again tomorrow before you export. Keep the original and export copies.

A camera used outdoors needs very little, but it needs that little consistently. Five things account for nearly every avoidable problem.

• Sensor dust. It shows as soft dark specks in exactly the same place on every frame, most visible at small apertures against a plain sky. Change lenses with the body switched off and the opening pointed down, and do it briskly. Run the built-in cleaning cycle, use a hand blower rather than canned air, and leave wet swabbing to someone practised with the right swab size — the sensor filter scratches, and the scratch is permanent.
• Batteries in the cold. Capacity falls in the cold and comes back when the cell warms, so a dead-looking battery in your pocket is often a working one twenty minutes later. Carry a spare inside your coat and rotate them. Coming back indoors, put the camera in the bag first and let it warm up closed, so the condensation forms on the bag instead of the glass and the sensor chamber.
• Lens cloths. Blow the grit off before anything touches the glass — a cloth dragged across sand is how coatings get scratched. Then a clean microfibre cloth, or a drop of lens fluid on the cloth and never on the element, working from the centre outwards. Wash cloths without fabric softener. A little dust on the front element affects the picture far less than people fear; a fingerprint left for months does not.
• Strap and bag habits. Use a strap you trust and shorten it so the body does not swing into a wall when you crouch. Leave the hood on: it is mostly impact protection, and it keeps stray light off the front element on a bright day. Pad the bag with dividers so nothing rattles against anything else on the walk home.
• Storage. Damp is the real enemy — fungus grows inside lenses left in warm, humid dark and etches the coatings. Dry everything before it goes away, keep a sachet of silica gel in the bag, and store lenses somewhere with moving air rather than sealed in a case for the winter.