Lens Optics and Selection Flashcards

What does the term 'bokeh' refer to in photography?

Answer: The aesthetic quality of the out-of-focus blur

Bokeh describes the visual quality of the out-of-focus areas in an image, determined by the lens's optical design and aperture shape.

A photographer needs to shoot wildlife from 100 feet away. Which focal length is MOST appropriate?

Answer: 400mm

A 400mm telephoto lens provides the reach needed to capture distant wildlife without disturbing the animals.

What is 'focus breathing' in a lens?

Answer: A change in the apparent focal length as focus distance changes

Focus breathing is the unintended change in a lens's angle of view as it racks through its focus range, which is particularly problematic for video work.

Which aperture value provides the WIDEST depth of field?

Answer: f/16

f/16 is a small aperture that allows more of the scene to appear in focus, creating a wide depth of field.

What is a 'prime' lens?

Answer: A lens with a fixed focal length

A prime lens has a single fixed focal length, as opposed to a zoom lens that covers a range of focal lengths.

Chromatic aberration appears in photographs as:

Answer: Color fringing along high-contrast edges

Chromatic aberration occurs when a lens fails to focus all wavelengths of light at the same point, causing colored fringing—often purple or green—along high-contrast edges.

What does 'IF' (Internal Focusing) mean in lens design?

Answer: The lens does not change length when focusing

Internal focusing lenses adjust focus by moving internal elements, so the physical length of the lens and front element position remain constant.