Zebra pattern

A visual warning that image highlights are being overexposed and used especially during video recording. The overbright areas are marked by moving diagonal stripes (hence zebra) leaving you to decide whether to reduce the exposure or to leave it if the highlight areas are unimportant.

White balance

An adjustment made by the camera to neutralise colour shifts in the lighting. Digital cameras offer an auto white balance option where they choose the correction, or you can select manual white balance ‘presets’ when you want to control the camera’s colour rendition yourself. White balance adjustments are made using ‘colour temperature‘ and ‘tint‘.

Warmth

A non-technical way of describing the colour temperature of the light in a scene. Pictures taken with a low sun have ‘warmth’ because the light takes on a golden colour. Many photographs – landscapes, for example – can be enhanced with a little additional ‘warmth’.

Bayer sensor

Most camera sensors use a single layer of photosites (pixels). These are only sensitive to light, not colour, so a mosaic of red, green and blue filters (the ‘bayer pattern’) is placed on top of the sensor’s photosites so that individually they capture red, green or blue light. When the camera processes the sensor data to produce an image, it ‘demosaics’ the red, green and blue data, using colour information from surrounding photosites to ‘interpolate’ full colour data for each pixel.

Active D-Lighting (Nikon)

An exposure mode on some Nikon digital cameras which balances up the exposure in high-contrast scenes. The camera reduces the exposure to make sure it captures bright highlight detail and then processes the image to brighten up dark shadows. It can be applied in different strength settings.

Action cam

A small, simple and largely automated video camera (you can also shoot stills) designed to attach to a helmet, handlebars, surfboard or any other kind of object and provide dramatic first-person video of adventure sports and other activities. Almost all use fixed focal length super-wideangle lenses and shoot full HD video – some can shoot 4K.

ACROS (Fujifilm)

Black and white film simulation mode added to newer Fujifilm cameras. It’s designed to give richer, more intense tonal rendition than the regular monochrome film simulation.

AA batteries

These are used rarely in digital cameras (except in some cheap point and shoot models) but used extensively in external flashguns and battery grips. Alkaline AAs will do in an emergency, but rechargeable NiMH batteries are more cost effective and last longer between charges.

5-axis stabilisation

The latest kind of image stabilisation technology, where the camera’s sensor can be tilted or shifted on 5 axes to counter a much wider range and types of movement than regular lens-based image stabilisers, and it’s a particular advantage for video, where these additional movements can pose problems during handheld filming. 5-axis stabilisation used in the Pentax K-1 full frame DSLR, Olympus OM-D mirrorless cameras and the latest Sony A7-series compact system cameras.

4K video

The latest consumer video standard, with a horizontal resolution of 4,000 pixels or thereabouts. 4K video is appearing on an increasing number of cameras and even smartphones, and 4K TVs are gaining in popularity. Strictly speaking, the dimensions for 4K video are 4.096 x 2,160 pixels and the aspect ratio is slightly wider than the 16:9 standard for HD video. In fact, what most makers and users are referring to is UHD video at 3,840 x 2,160 pixels, which does have a true 16:9 aspect ratio.