Camera settings for VidSync

Using a camera to the best of its ability is important to getting the most from VidSync data. The best settings depend on the smallest feature that must be visible, the fastest action that must be resolved, the range of subject distances, the length of the recording, and the computers and storage available for analysis. Camera settings should be chosen through representative tests rather than from a universal recipe.

Settings are only one part of the recording system. See Lighting and cinematography for VidSync data for visibility, motion blur, glare, contrast, and pilot review, and Video cameras and mounts for camera selection, housings, geometry, and rigidity.

Settings to record and keep fixed

Record the resolution, frame rate, scan mode, shutter speed, aperture, ISO, exposure mode, focus, focal length or zoom, white balance, stabilization mode, lens-correction settings, codec, and bitrate. Cameras often save some of this information as metadata, but a field record is easier to review and preserves settings that may not survive transcoding.

For measurements that depend on a fixed relationship between the scene and the recorded pixels, changes in focus, focal length, digital crop, stabilization, lens correction, or camera position can matter. Secure adjustable controls when practical and record the time of every change. Footage recorded after a change may require separate reference or calibration material.

Resolution and field of view

Resolution describes the number of recorded pixels. More pixels can preserve finer detail, allow a subject to occupy a smaller part of a wide scene, and make small landmarks easier to identify. The benefit depends on the lens, focus, motion blur, noise, compression, and the camera’s actual image processing. A high-resolution file cannot recover detail that the optical system never resolved.

Choose a resolution by examining how many pixels the subject and its smallest required features occupy at the expected distance. A resolution that is adequate for detecting a fish may be inadequate for locating a fin edge or identifying markings. Test the least favorable subject positions, including the most distant part of the working volume.

Higher resolutions increase storage, decoding work, memory use, and sometimes heat or recording limits. VidSync may need to play several clips at once, so test the intended resolution and codec with the intended number of simultaneous cameras on the Mac that will be used for analysis. Perform the test with recordings of realistic duration and image complexity.

Resolution modes can also change the portion of the sensor used, the available frame rates, stabilization crop, rolling-shutter behavior, or lens correction. Do not assume that two modes preserve identical geometry simply because they use the same lens and focal-length setting.

Frame rate and scan mode

Frame rate determines how often the camera records an image. Higher frame rates provide more samples of rapid motion and more possible instants at which synchronized views can be compared. They also increase the data rate or force compromises in resolution and compression. Select a frame rate that resolves the fastest event of interest, then verify it with representative motion.

Progressive-scan video records each frame as a complete image. Interlaced video combines alternating rows recorded at different times, so a moving object can appear as two interleaved positions when paused. Record progressive video whenever possible. Historical interlaced footage can be deinterlaced, but interpolation cannot fully reproduce frames that were never recorded as complete images.

Some phones, action cameras, screen recorders, and automatic camera modes produce variable-frame-rate video. The nominal frame rate may be 30 or 60 fps while the actual interval between frames changes. This can complicate synchronization and time-based measurements. Before fieldwork, inspect representative files, confirm that they play and step predictably in VidSync, and compare visible timing cues across cameras. If conversion to constant frame rate is necessary, preserve the original files and verify the converted timing against known cues.

Shutter speed and motion blur

Shutter speed determines how long each frame gathers light. During that interval, a moving subject continues to move, producing blur. A high frame rate does not guarantee sharp frames when the exposure time remains long.

Choose shutter speed using the fastest movement and smallest moving feature that observers must distinguish. Fish turns, fin tips, prey strikes, drifting particles, and rapidly moved reference objects may require shorter exposures than a slowly moving body. Shorter exposures require more light, a wider aperture, a higher ISO, or some combination of these. Test actual motion under the expected lighting.

Aperture, ISO, and exposure mode

Aperture controls how much light passes through the lens. A smaller aperture opening increases depth of field, helping subjects at different distances remain in focus, but it reduces the light available for each frame. Extremely small apertures can also soften detail through diffraction.
ISO controls the amplification applied to the camera signal. Higher ISO settings permit shorter exposures or smaller apertures in dim conditions, but they increase noise and can remove fine detail through noise reduction.
Shutter speed controls exposure time and motion blur. It should be chosen with the movement of the subject in mind rather than used only as a way to brighten or darken the image.

Automatic exposure is convenient and may be appropriate when light changes substantially during a long deployment. It can also react to passing shadows, bright objects, or changes in the background, altering brightness and motion blur during a sequence. Manual exposure keeps these characteristics stable when the illumination is predictable. Test how the chosen mode behaves during the events expected in the study.

Evaluate exposure on the subject and on any reference objects. Bright regions should retain needed internal detail, and important shadows should remain distinguishable. The camera display may be too small to reveal clipping, noise reduction, or motion blur, so inspect sample files on a computer.

Focus settings

Autofocus can shift between the subject, background, suspended particles, and foreground objects. A change in focus can alter the optical geometry as well as the sharpness of the image. For rigid, calibrated setups, manual focus is usually preferable when the subject remains within a predictable range. If autofocus is required, test its stability and collect the reference material needed for the way the camera will actually operate.

Users of adjustable manual-focus cameras should test the complete recording system at the intended subject distances. Housing ports and the air-water interface affect focus, so a distance marked on the lens may differ substantially from the actual focused distance underwater. With dome ports, the lens focuses on a virtual image located relatively close to the port even when the real subject is much farther away.

Depth of field should cover the full region in which observations will occur. Check the nearest and farthest likely subject positions in every camera. After focusing, secure controls that can slip during handling. I have found that DSLR focus rings sometimes move while cameras are placed in housings or mounted, and a removable ring of tape can prevent accidental changes.

Focal length and zoom

Focal length determines field of view and the apparent size of the subject. A similar view of one subject can often be obtained by placing a wide-angle camera close to it or a narrower-angle camera farther away. The environment may decide which arrangement is possible, especially in tight spaces or when subjects avoid nearby equipment.

For underwater work, a shorter camera-to-subject distance usually improves contrast and reduces the amount of scattering water and debris between them. Greater camera distance can be useful when subjects occupy a broad range of distances. Consider two fish separated by 1 m along the camera’s viewing direction. If the camera is 0.2 m from the nearer fish, the second fish is six times farther away and appears much smaller. If the camera is 3 m from the nearer fish, the second fish is only about one-third farther away, so their apparent sizes are more similar.

A close, wide view is often effective for underwater fieldwork. A more distant, narrower view may suit a laboratory tank when cameras can be placed outside the tank and subjects range across its depth. Test configurations before fixing the study design. After choosing the focal length, secure any zoom ring or mechanism that can move and record the setting.

Stabilization, cropping, and lens correction

Optical, sensor-shift, and digital stabilization are designed to make ordinary footage look steadier. They may move the image, change the effective optical center, or vary the crop from frame to frame. For a camera on a rigid mount, disable stabilization unless testing shows that the chosen mode preserves the fixed image geometry required by the study.

Some cameras apply dynamic cropping, horizon leveling, rolling-shutter correction, or automatic lens-distortion correction. These operations can warp or reposition the image even when the physical camera does not move. Record whether each feature is enabled and keep the choice fixed through the observation and associated reference footage. A setting with a familiar label may behave differently among camera models or recording modes.

White balance and in-camera processing

Stable white balance is helpful when color or markings are used for identification. Automatic white balance can change as a subject, light, or background enters the frame. Picture styles, sharpening, noise reduction, and high-dynamic-range modes also affect fine detail. Strong processing may create sharp-looking edges while removing subtle texture. Keep these settings consistent and evaluate representative paused frames.

Video formats and transcoding

Containers, codecs, bitrates, storage estimates, interlacing, variable frame rate, file segmentation, and conversion require a complete workflow rather than a single camera setting. See Video Formats and Transcoding for detailed guidance.

The dedicated page includes the approved H.264 and HEVC storage examples, preservation of camera originals, representative conversion tests, a reproducible FFmpeg and FFprobe procedure, and the use of Codex or Claude Code to construct and document safe batch workflows. Test the chosen files in VidSync on the intended Mac before processing a full dataset.

Test the complete recording chain

Before fieldwork, make representative recordings with every camera and process them through the complete intended workflow. Copy or transcode the files, import them into VidSync, load the expected number of simultaneous views, synchronize them using a visible cue, step through fast motion, and inspect difficult frames. Repeat the test after firmware, recording-mode, codec, or conversion changes.

Confirm resolution, frame rate, progressive scan, and constant timing.
Check motion blur, focus, depth of field, exposure, noise, and compression artifacts.
Verify that stabilization, cropping, and lens-correction settings remain fixed.
Confirm that multiple files play together and can be inspected frame by frame.
Record all settings and retain the original files.

Add the verified settings and file-handling procedure to the study’s field protocol.