In “The Work of Art in the Age of Mechanical Reproduction”, Walter Benjamin describes an interesting way of judging “realness”:
The authenticity of a thing is the essence of all that is transmissible from its beginning, ranging from its substantive duration to its testimony to the history which it has experienced. Since the historical testimony rests on the authenticity, the former, too, is jeopardized by reproduction when substantive duration ceases to matter. And what is really jeopardized when the historical testimony is affected is the authority of the object. One might subsume the eliminated element in the term “aura” (…).
One of the best insight from his famous essay is something I had never previously considered—possibly because I had grown up in an age of reproduced, broadcasted art. It is the loss of immediacy that used to prevail when an actor performed before an audience versus performing for a camera (for later viewing).
What matters is that the part is acted not for an audience but for a mechanical contrivance — in the case of the sound film, for two of them. (…) for the first time — and this is the effect of the film — man has to operate with his whole living person, yet forgoing its aura. For aura is tied to his presence; there can be no replica of it. The aura which, on the stage, emanates from Macbeth, cannot be separated for the spectators from that of the actor. However, the singularity of the shot in the studio is that the camera is substituted for the public. Consequently, the aura that envelops the actor vanishes, and with it the aura of the figure he portrays.
The same is true for photography: no matter how “accurate” a photo, it can never be real.
The camera may not lie, but any photo has stripped away the “aura”, that which only exists in person, and which arguably constitutes the real.