The ABC of Photography – X

XLD

Stands for extra-low dispersion, the glass used in some Tamron lenses to reduce chromatic aberration.

XMP

Stands for an extensible metadata platform. A labeling technology used by a number of image-editing programs, including the Photoshop family. It records information about a file and is usually embedded within the file itself. With raw files, the XMP information is recorded separately.

XR

Stands for extra refractive, a type of glass used in Tamron lenses. It can bend light at wider angles than normal glass, helping to make the overall size of the lens smaller.

Sources:  Pixabay, NASA,Wikipedia, Susan Wingfield Lamar High School