Meaning of CANDID photograph.

A candid photograph is a photograph captured through motion mostly, without creating a posed appearance. This is achieved by avoiding prior preparation of the subject and by either surprising the subject or by not distracting the subject during the process of taking photos. Thus, the candid character of a photo is regardless of the subject's knowledge or consent as to the fact that photos are being taken, and regardless of the subject's permission for subsequent usage such as distribution, but related to the apparent absence of posing. It is distinguished from making secret photography by the photographer usually remaining discernible to the public and not wearing cover.

-Ref: Wikipedia.