Exposure basics

Every photo is a balance of three controls. Change one and you must pay with another — that's the whole game. Five minutes here explains every recommendation in this app.

Aperture

f-number

How wide the lens opens. A low f-number like f/1.8 opens wide: lots of light and a soft, blurred background. A high f-number like f/11 keeps everything sharp from front to back.

Trade-off: Wide = more light + more background blur, but a thinner sharp zone. Narrow = more of the scene sharp, but less light.

Shutter speed

seconds

How long the sensor is exposed. 1/1000s freezes a football mid-air; 1 second turns car lights into streaks.

Trade-off: Fast = sharp action, but little light. Slow = more light and motion streaks, but handheld blur below about 1/60s.

ISO

100 – 6400+

How much the camera brightens the picture. Low ISO (100–200) gives the cleanest files; high ISO (3200+) lets you shoot in the dark but adds grain.

Trade-off: Higher ISO = brighter photos with more grain. It is the control you raise last, after aperture and shutter.

Camera modes, decoded

AutoThe camera decides everything. Fine until it gets it wrong — and you'll have no idea why.

P (Program)Camera picks shutter and aperture; you control ISO, flash and exposure compensation. A gentle step up.

A / Av (Aperture priority)You pick the aperture (background blur vs sharpness), the camera picks the shutter. The mode most photographers live in.

S / Tv (Shutter priority)You pick the shutter speed (freeze vs blur), the camera picks the aperture. Good for sport and panning.

M (Manual)You pick everything. Essential on a tripod for night and interior work; overkill for quick candid shots.

How much light is there?

The light decides your ISO more than anything else. These are the typical ranges:

Bright daylight

ISO 100–200

There is lots of light, so keep ISO at its lowest and watch for blown-out highlights.

Cloudy

ISO 200–400

Flattering light for faces. A slightly higher ISO keeps your shutter speed safe.

Golden hour

ISO 100–800

The light falls quickly — check your exposure every few minutes.

Indoor bright

ISO 400–1600

Brighter than it looks to your eye, but still far darker than outdoors.

Indoor dark

ISO 1600–6400

Open the aperture fully before you raise ISO further.

Night

ISO 1600–6400

On a tripod you can drop ISO right back to 100 and use a long exposure instead.

Flash available

ISO 400–1600

Flash lights your subject, so ISO can come down. Bounce it off a ceiling for softer light.

Mixed lighting

ISO 800–3200

Colours can look strange. Shoot RAW so white balance can be fixed afterwards.

Two habits worth learning early

Shoot RAW

RAW files keep all the information the sensor captured, so brightness, colour and white balance can be fixed afterwards. JPEG throws that away the moment you press the button. Use RAW for anything important.

Take one frame, look, adjust

No starting setting is final. The screen and histogram tell you more than any guide — too dark? Open the aperture, slow the shutter or raise ISO. Too blurry? Speed up the shutter. Adjust one control at a time.

Try it with my camera