Photography Lens Optics and Selection 3

Question 1

What is the 'hyperfocal distance' of a lens?

Accepted Answer

The focus distance that maximizes depth of field from half that distance to infinity

Answer

The hyperfocal distance is the closest point at which a lens can be focused while keeping objects at infinity acceptably sharp, maximizing overall depth of field.

Question 2

A macro lens with a 1:1 magnification ratio means:

Accepted Answer

The image on the sensor is the same size as the real subject

Answer

A 1:1 magnification ratio means the subject is reproduced at life-size on the camera sensor—a 10mm insect will appear 10mm on the sensor.

Question 3

Which type of lens distortion causes straight lines to bow outward from the center?

Accepted Answer

Barrel distortion

Answer

Barrel distortion causes straight lines to bow outward, and is most common in wide-angle and zoom lenses at their widest focal lengths.

Question 4

What advantage does an ED (Extra-low Dispersion) glass element provide?

Accepted Answer

Reduced chromatic aberration

Answer

ED glass bends different wavelengths of light more uniformly, significantly reducing chromatic aberration and producing sharper, more color-accurate images.

Question 5

What does 'T-stop' measure, and how does it differ from f-stop?

Accepted Answer

T-stop measures actual light transmission; f-stop measures the geometric aperture ratio

Answer

T-stop accounts for actual light lost to glass absorption and reflection inside the lens, while f-stop is purely a geometric ratio of focal length to aperture diameter.

Photography Practice Test

Photography Practice Test

Photography Lens Optics and Selection 3