That's just for show. A grid is visible in the background of the drawing. Such a grid is used to set up the initial outlines, by copying it from the reference

That's just for show. A grid is visible in the background of the drawing. Such a grid is used to set up the initial outlines, by copying it from the reference photo with a grid drawn on top of it (typically done in Photoshop). Other artists use a projector to trace. As another commenter mentioned, the depth of field removes any doubt that a photo is used as a reference. Picking up and placing back the watch to see details would constantly change the lighting, especially in the details. It is impossible to get such a level of detail by "drawing from nature", even in studio conditions. It's not a coincidence that paintings only became more realistic after the invention of photography.