To quote an extract from Fox Talbot’s “The Pencil of Nature” - But when the sensitive paper was placed in the focus of a Camera Obscura and directed to any object, as a building for instance, during a moderate space of time, as an hour or two, the effect produced upon the paper was not strong enough to exhibit such a satisfactory picture of the building as had been hoped for. The outline of the roof and of the chimneys, &c. against the sky was marked enough; but the details of the architecture were feeble, and the parts in shade were left either blank or nearly so. The sensitiveness of the paper to light, considerable as it seemed in some respects, was therefore, as yet, evidently insufficient for the purpose of obtaining pictures with the Camera Obscura; and the course of experiments had to be again renewed in hopes of attaining to some more important result.

Compare this with what we are able to achieve in photography today, chemical/digital or otherwise. If you accept that a photograph is probably the nearest we have to a time machine. Then try and imagine how this concept may be developed in the future to actually provide that time machine, to look and experience both the past and future.