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What happens when

You tap the shutter button

From a tap on glass to a finished JPEG in under a second, a chain of hardware and software decisions is made.

~700 ms6 stepsRelated exhibit: How a Camera Captures Light

Following the request, step by step

Scroll through. Each step is something that genuinely happens, with the time it typically takes.

  1. Step 01<10 ms

    The tap is registered

    The touch controller reports where your finger landed.

    The capacitive panel detects the disturbance in its field grid and reports coordinates to the system. The camera app recognises the tap on the shutter control.

  2. Step 02<5 ms

    Exposure is chosen

    Aperture, shutter time and ISO are selected for the scene.

    The image signal processor analyses the live preview: how bright is it, is anything moving, is there a face. It then picks an exposure combination that balances brightness against blur and noise.

  3. Step 0330–300 ms

    Autofocus locks

    The lens moves until contrast is maximised at the focus point.

    Phase-detection pixels on the sensor estimate how far out of focus the subject is, and the lens is driven to close that gap. Low light makes this slower because there is less contrast to measure.

  4. Step 041/60 s

    The sensor is exposed

    Photons are collected as electrical charge.

    The shutter uncovers the sensor for the chosen time. Each photodiode accumulates charge in proportion to the light it receives. Motion during this window becomes visible blur.

  5. Step 0550–200 ms

    The frame is read and processed

    Raw data becomes a viewable image.

    The sensor is read row by row and digitised. The image processor demosaics the colour pattern, applies white balance, reduces noise, sharpens and compresses the result — all with dedicated hardware so it costs little battery.

  6. Step 0610–50 ms

    The photo is stored

    The finished file is written to flash and indexed.

    The JPEG or HEIC file is written to storage, added to the photo library, and queued for any cloud backup. At this point the operation is complete and the camera is ready for the next shot.

Drive it yourself

The same sequence as a diagram you can play and step through.

rayslimited byexposechargeraw dataScenereflected lightLens Elementsfocuses raysApertureiris diameterShutterexposure timeCMOS Sensorphotons to chargeReadout & ADCcharge to numbersImage Processordemosaic, denoise
Step 1/4f/2.8 cone
1

1 · Collect Light

The lens gathers a cone of rays from every point in the scene and bends them toward the sensor.

Part inspector

Select any part of the diagram to read what it does. Play the sequence, or step through it yourself.

More scenarios

6 steps · ~400 ms end to end

You type a web address and press Enter

Follow a single request from your keyboard to a server on another continent and back again, in the time it takes to blink.

Follow the sequence5 steps · ~120 ms to display on

You press the power button

A short press that looks trivial hides a careful dance between the power management chip, the processor and every subsystem attached to it.

Follow the sequence