Digital Camera Basic Knowledge Lens

Focal length and angle of viewFixed focal length lens and zoom lensMacro mode and macro lenses

Focal length and angle of view

Focal length and angle of view

The distance from the center of the lens to the image focal point (=image sensor surface) is known as the focal length. It is expressed in millimeter (mm) units. A lens with a short focal length is a wide-angle lens and one with a long focal length is a telephoto lens.

The angle indicating the width of the field included in the photo is called the "angle of view." A wide-angle lens has a wide angle of view and a telephoto lens has a narrow angle of view.

  • 28 mm
  • 35 mm
  • 50 mm
  • 85 mm
  • 105 mm
  • 135 mm
  • 200 mm
  • 300 mm

Relationship between focal length and angle of view

Lenses are categorized based on their focal length.

  • Ultra wide-angle lens With a focal length equivalent to 24 mm or less, this type of lens has an angle of view even wider than a standard wide-angle lens.
  • Focal length (35 mm format conversion) Ultra wide-angle 24mm or less Wide-angle Around 28 to 35mm
  • Wide-angle lens With a focal length of around 28 to 35 mm, this type of lens can, as the name implies, take photos with a wide field.
  • Normal lens This is a lens with a focal length of around 50 mm. With this type of lens you can photograph the subject with a sense of distance similar to what you see with your eyes.
  • Normal Around 50mm Medium telephoto Around 85 to 135mm
  • Medium telephoto lens Mid-way between a normal lens and a telephoto lens, this type of lens has a focal length of around 85 to 135 mm.
  • Telephoto lens With a focal length of around 200 to 300 mm, this type of lens can take photos in which far away objects appear large.
  • Telephoto Around 200 to 300mm Super telephoto 400mm or more
  • Super telephoto lens With a focal length equivalent to 400 mm or more, this type of lens has an angle of view even narrower than a standard telephoto lens.

What does does"35 mm format conversion" refer to?

Even if the focal lengths of the lenses of two digital cameras are the same, the angle of view can vary depending on the size of the image sensor used in each. To make it easier to understand angle of view, focal length is often expressed as "__ mm equivalent," which means it has been converted to the 35 mm film camera format that has been historically the most common. Here on this site also, we state focal lengths that are converted into 35 mm film camera format.


Fixed focal length lens and zoom lens

Lenses can be categorized overall as fixed focal length lenses and zoom lenses.

* The GXR interchangeable unit camera system has camera units with a fixed focal length lens and camera units with a zoom lens.

Fixed focal length lens
Fixed focal length lens
This is a lens with a single fixed focal length. GR DIGITAL series cameras use a fixed focal length lens.
Zoom lens
Zoom lens
A lens in which the focal length can be continuously varied is a zoom lens. CX series cameras use a zoom lens.

What is a conversion lens?

A conversion lens is attached to a lens to enable it to take photos with a wider angle or stronger telephoto magnification.

Wide conversion lens Before attaching (28mm)Wide conversion lens After attaching (21mm)
Wide conversion lens

Attaching a 0.75x wide conversion lens to a 28 mm lens gives an angle of view equivalent to a 21 mm ultra wide-angle lens.

Before attaching (28 mm)After attaching (21 mm)Display side by side
Before attaching (72 mm)After attaching (135 mm)
Teleconversion lens

Attaching a 1.88x teleconversion lens to a 72 mm lens gives an angle of view equivalent to a 135 mm medium telephoto lens.

Before attaching (72 mm)After attaching (135 mm)Display side by side

Link to more information on Ricoh conversion lens

http://www.ricoh.com/r_dc/option/lens/


Macro mode and macro lenses

When you want to fill the frame with photos of flowers or small objects, if you just move the camera close to the subject, the camera will not be able to focus. With an interchangeable lens camera, it is necessary to use a macro lens, but with a compact digital camera you can focus on close-up subjects by just turning on the camera’s macro mode.

Macro mode OFFMacro mode ON
Macro mode

With a zoom lens, when you turn on macro mode and move as close as possible while still keeping the subject in focus, the minimum distance to the subject and the size of the subject in the frame will differ depending on whether the lens is at a wide-angle or telephoto zoom position. With a wide-angle setting you may be too close and with a telephoto setting you may be too far away so adjust the focal length to find the one that makes it easiest to take the shots you want.

Macro mode OFFMacro mode ONDisplay side by side
What is a macro lens?
What is a macro lens?

This is a lens used for close-up photography. A macro lens can shoot from a distance closer to the subject than a regular lens. The GXR interchangeable unit camera system has a camera unit with a 50 mm macro lens.
Link to more information on GXR camera unit


Focal length and angle of viewFixed focal length lens and zoom lensMacro mode and macro lenses

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