Filming for SwimLab

The quality of your annotation comes down to the quality of your footage. Good positioning and settings cost nothing — they just need a few minutes of preparation before the session or meet starts.

The Golden Rules

End-on beats side-on for races — you see the touch wall clearly
Level with the water — avoids parallax error on wall touches
60fps beats 30fps — doubles your split precision
Stable beats handheld — a railing, tripod, or flat surface is always better
5 seconds before the start — always start recording before the starter’s signal

Camera Position

Race footage (end-on)

Film from the finish end of the pool, looking down the lane toward the start. This gives you:

Clear sight of the start (reaction time and feet-off-block)
Clear sight of every turn touch
Clear sight of the finish touch

Position the camera at water level or just above — aim for the top of the lane rope or pool surround. Filming from the stands looking down creates a parallax problem: the far wall looks closer than it is, and the touch moment is harder to judge accurately.


                    ← camera here
┌──────────────────────────────────┐
│  ⊲ lane ⊳                       │ ← water level
│  ⊲ lane ⊳  ←────── pool ──────  │
│  ⊲ lane ⊳                       │
└──────────────────────────────────┘
                                   ▲
                            finish wall (camera end)

Training footage (side-on or underwater)

For technique analysis, a side-on angle lets you see:

Stroke cycle mechanics
Body position and rotation
Kick pattern and depth

An underwater angle (through the observation window, or a GoPro on a pole) shows:

Underwater dolphin kicks
Breakout position
Turn mechanics clearly

For the most complete analysis, film the same swim from two angles if you have multiple cameras: end-on for splits and touch accuracy, side-on for technique.

Camera Settings

Frame rate

Setting	Precision per marker	Best for
60fps	±16ms	Competitive analysis, all races
50fps	±20ms	Acceptable for training
30fps	±33ms	Minimum usable; avoid for meets
25fps	±40ms	Avoid

On most phones: Settings → Camera → Record Video → 1080p at 60fps

On a dedicated camera: set the frame rate in the video menu. If 60fps isn’t available at 1080p, try 720p at 60fps — resolution matters less than frame rate for split accuracy.

Resolution

1080p is the recommended minimum. 4K is supported but creates larger files and slower upload times without meaningful benefit for split analysis. For underwater cameras on a pole, 1080p is usually the best option at higher frame rates.

Exposure

Outdoor pools in direct sun: use your phone’s HDR mode if available; the lane markings can wash out otherwise
Indoor pools: most indoor lighting is fine; avoid “Auto” if the camera keeps hunting between exposures
Underwater: if using an underwater camera, set a fixed white balance for pool lighting

Phone-Specific Tips

iPhone

Open Settings → Camera → Record Video and select 1080p at 60 fps
Use the back camera, not the front — better optical quality and stabilisation
Lock exposure before recording: open Camera, tap-and-hold on the water to lock AE/AF
Use a phone clip on a railing, or a small GorillaPod — handheld video is hard to annotate

Android

Settings vary by manufacturer, but look for:

Resolution → 1080p (Full HD)
Frame rate → 60fps (sometimes labelled “Smooth” or “HFR”)
Stabilisation → on for handheld; off or optical-only if on a tripod

Storage

A 3-minute race at 1080p/60fps is roughly 500 MB–1 GB depending on your phone. Before a meet:

Check free storage — aim for at least 20 GB free for a full-day meet
Or bring a lightning/USB-C flash drive to offload between sessions

What to Avoid

Problem	Why it matters	Fix
Filming from the stands at a steep angle	Touch moments are obscured by the pool edge	Move to poolside, water level
Handheld camera	Drift makes scrubbing to exact frames harder	Use a railing or tripod
Starting recording at the starting signal	You miss the reaction time and the block position	Start 5 seconds early
Zooming in heavily on a phone	Digital zoom reduces quality and makes it harder to see the full lane	Stay wide; zoom in post by scrubbing frame-by-frame in SwimLab
Filming through a window without cleaning it	Reflections and smears ruin footage	Wipe the window with a dry cloth

Checklist Before Each Session

Frame rate set to 60fps
At least 10 GB storage free
Camera mounted or resting stably
Camera at water level (end-on filming)
Recording started 5 seconds before the start signal

Next Step

Ready to upload? Upload a Race →