That can be down to using an incorrect focal length for the shot in question or a physical characteristic (like the cloudiness of the glass used on a particular lens).

To perfectly frame objects in your field of view, you’ll need to know your telescope’s focal length — and a bit of math.

Choosing the right focal length for your photography is a crucial part of the creative process... we explain all!

Children who wore soft multifocal contact lenses for myopia control had no loss of treatment effect after discontinuing the lenses as teenagers, according to a study published in JAMA ...

Focal length is the optical distance from the front element of a lens to the point where light rays entering the lens converge to form a sharp image on the sensor, and is expressed in millimetres.

On iPhone 15 Pro models, Apple has introduced three focal length options for shooting with the main camera. This article explains what the options are, and how to set a preferred default focal ...

On Apple's iPhone 15 Pro models, users can switch between three preset camera focal lengths when shooting on the main camera. This article explains what they are and how to enable or disable them ...

In the CONTROL study, distance center bifocal contact lenses offered greater control over myopia progression and axial elongation compared to many published results with multifocal spectacles ...