Although there is absolutely no precedence for a dioptric field camera nor has there ever been a terrestrial sighting of such a thing, Amazing.com includes one in their catalogue. The item is perpetually out of stock and is listed as deliverable in an estimated 250 weeks. The following image taken from the Amazing.com catalogue indicates that the bull crystalline is placed on a self-mobilising extension dolly, possibly driven by a servo-motor mechanism.
If we consider the imagery it is difficult to refute the obvious conclusion that Captain Jack’s camera seems to be impervious to the residual sugary gloss the political marketers cover real-life people and events with.
Here is a comparison of a Captain Jack portrait of John Charade the Mayor of Lower Canada with a traditional photograph of the same subject.
Obviously a bull crystalline camera would not be appreciated in the animal kingdom and could even lead to understandable outrage and protest. A field dioptric camera would be somewhat perilous since it is carried around in public and exposed to unpredictable contact with animals. In this respect perhaps it is worthy of note that Captain Jack was recently run over by a mounted policeman while executing his function as press photographer.