Video tests

Video viewing test

Monitors, projectors and video cards are adjusted to sRGB colour space. All measurements and recordings are made using automatic exposure and automatic white balance settings. Two one minute video recordings are made of a scene featuring people with colourful clothes, other objects with fine details, and realistic artificial plants at different distances. The automatic focus system and white balance is switched on if possible.

The camera is mounted on a tripod. About a third of the take is recorded while panning and another third while zooming. Lighting for the tests is under the following lighting conditions at the targets:

• Daylight conditions, 3500 lux (D65)
• Low light, 12 lux.

These recordings are replayed on profiled and calibrated high-quality liquid crystal monitors or projectors with high resolution (full HD with 1920 x 1080 pixels and at least 24 frames per second). The test panelists evaluate colour fidelity and view the actual objects with appropriate illumination. The recorded images are rated according to the following criteria:

• Sharpness (how faithfully structures are reproduced)
• Colour fidelity (colour neutrality and colour noise)
• Exposure and contrast gradation (also in highlights and in dark areas)
• Image and focusing irregularities
• Overall image quality.

Resolution

We take video recordings at maximum and minimum focal length (using the same test chart used for still images) and rate them for the resolution of the images at the centre and corners.

Macro recording

We take video recordings at maximum magnification and rate the images for resolution and overall quality. Particular attention is paid to any issues with focusing, exposure or contrast.

Audio quality

All measurements and recordings are made using the camera's automatic gain control settings. An audio stereo sample (classical music with high dynamic range) with a duration of about 30 seconds is played over two high-quality loudspeakers in a room.

First, a reference recording from these samples is produced on a digital recorder with a high-quality stereo microphone at a distance of 2 metres. The sound pressure level at the location of the microphone is at an average of 65 dB(A). Two audio recordings are made with each camera being tested, under the same conditions. Recording is with the built-in microphone in automatic mode and we create possible noise by using the zoom button or zoom drive.

We then listen to the recordings using high-quality headphones and rate the overall audio quality at the original volume. Problems with motor-, zoom- and button-noises are commented on separately.

Device ready for operation

The device is switched off for at least a minute then switched on again, and we measure the time it takes before the first video frame is taken.