Understanding Abbe Value in Photography: A Guide to Depth of Field and Bokeh

Abbes (or Abbe) is a unit of measurement used in optics and photography. It is defined as the ratio of the diameter of a lens to the diameter of its aperture stop, expressed as a decimal value. The higher the number of abbes, the larger the lens opening relative to the lens size, which can result in a shallower depth of field and more pronounced bokeh (out-of-focus areas) in images.

For example, a lens with an Abbe value of 10 would have a larger aperture stop than a lens with an Abbe value of 5, assuming all other factors are equal. This means that the first lens would have a shallower depth of field and more pronounced bokeh compared to the second lens.

The Abbe value is named after its inventor, German physicist Ernest Abbe, who developed the concept in the late 19th century. It is still widely used today as a way to compare the relative aperture sizes of different lenses and to predict their optical performance.