Introducing Lytro’s glossary of useful terms

Here at Lytro, we’re building a glossary of frequently used terms and their definitions that you might encounter in VR, cinematography, digital imaging, photography and light. Our goal is to help educate and inform, while adding some context about how these various elements are a part of our work at Lytro. The glossary is intended to be an organic collection and is a work in progress. Please feel free to share any terms you think might be worthy to add. We’ll be regularly sharing new definitions in this blog.

parallax

Parallax occurs when closer objects appear to shift more than objects that are further away as your point of view shifts. Try shifting your head from side to side (position, not rotation) and notice how objects around you appear to move at different speed. This very noticeable difference in motion between objects near and far is parallax. In VR, when objects don’t have parallax, we interpret the scene as flat even if captured in stereo. Parallax is a key visual cue which allows the brain to understand the world around us, and is one of the obvious advantages that Light Field video provides over 360° video.

view volume

The view volume is the volume in space for which we have Light Field information. Every ray of light that intersects this volume is captured, giving the viewer six degrees of freedom (6DoF) within that volume. For Lytro live-action content, the viewing volume is proportional to the size of the camera rig and is roughly the width of the array. The experience outside the view volume can be varied according to the piece, but typically we convert the experience outside the volume to stereo spherical.

aperture

An aperture is an adjustable circular opening which allows more light to pass through a camera lens when it is open and less light as it closes. Changing the aperture affects depth of field as well as exposure and is one of the fundamental relationships in photography.

Aperture values (known as an f-stop, or f) on a lens refer the ratio of that lens’ length divided by the diameter of the opening. For example, a 100mm long lens with a 50mm wide aperture opening would have an f-stop value of f/2.0 (100 / 50 = 2), and an f/16 value means that the aperture is 6.25mm in diameter (6.25 x 16 = 100).  Wider apertures let more light in and create a shallower depth of field (a small area of focus): smaller apertures let less light in and create a deeper depth of field (a large area of focus). Using Light Field data, Lytro can virtually recreate a full range of aperture diameters from very large to very small, and allows you to control the depth of field in ways that a traditional cameras cannot.


About Steve Cooper 7 Articles

Director Product Marketing at Lytro, cyclist and owns a flame thrower

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