Google definition of Identity:

The fact of being who or what a person or thing is or a close similarity or affinity.

Identity within photography:

The relationship between photography and social identity is as old as the invention of the camera, despite the fact that its earliest developers thought that their newfangled device was best suited for other purposes. 

From our perspective, it’s easy to see why the camera was embraced by so many people, who thought of it as a means of self-representation, despite what its inventors proclaimed. Previously, those who could afford to have images made of themselves were almost invariably of the upper-middle and ruling classes. They had the income and leisure to sit for the portrait painter. But suddenly, with the camera, the power of such imagery came within reach of ordinary folk, which helped them express their identity through the images they created of themselves or even other people. 

Of course, these portraits and self-portraits had their share of fiction. Consider a picture of a Chinese migrant worker, who in the 1870s had made his way across the Pacific Ocean to California, taken a train across the American continent, and found temporary work as a shoemaker in a factory. One would never guess his lowly status as a migrant factory worker in the photograph; we might instead be tempted to regard him as something else, a man of taste and leisure, for instance, accessorized in the latest dapper fashion and proud to hold the latest books in English. As the photograph tells us, “identity” was quickly recognized as something that could be manufactured in front of the camera as easily as it might be discovered by it.

The constructed nature of identities is facilitated by photography. In very sophisticated ways, how identities are made in today’s globalized, interconnected, intensely visual world is often explored by photographers. In some cases, the ambitions that urged photography’s earliest sitters to take to the lens continue to inform these photographers’ practices.