An "infinity lens," more accurately understood as a lens focused at infinity, is a photographic lens setting where the lens is adjusted to bring objects at a very far distance (theoretically infinitely far) into sharp focus. This setting effectively creates an extraordinarily wide depth of field.
Understanding Infinity Focus
- Concept: Infinity focus means the lens is adjusted so that light rays from a distant object converge sharply on the camera's sensor or film.
- Depth of Field: As the reference mentions, infinity focus is similar to an extraordinarily wide depth of field.
- Practical Implication: When your lens is focused to infinity, everything from a relatively close distance to the lens all the way to the furthest visible objects will appear in focus. This does not mean everything is in focus, but rather a very broad range.
When to Use Infinity Focus
- Landscape Photography: Capturing expansive scenes where you want both foreground and background elements to be sharp.
- Astrophotography: Focusing on stars and other celestial objects, which are effectively at infinity.
- Situations Where Precise Focusing is Difficult: When manually focusing in low-light or rapidly changing situations.
- Achieving Maximum Depth of Field: When striving for a photograph with the greatest possible area in sharp focus.
Important Considerations
- Lens Markings: Many lenses have an infinity mark (∞). However, relying solely on this mark might not always guarantee perfect focus, especially with older lenses or lenses that have been slightly miscalibrated.
- Focus Peaking & Magnification: Utilize focus peaking (a feature in many modern cameras that highlights in-focus areas) and magnification in live view to fine-tune the focus at infinity.
- Hyperfocal Distance: While infinity focus brings distant objects into focus, understanding and using the hyperfocal distance (the closest distance at which a lens can be focused while keeping objects at infinity acceptably sharp) can further maximize the overall depth of field in a scene.
