Aside from some location photography in 1930s Honolulu and the fun of seeing famous personalities like Bela Lugosi and Dwight Frye in supporting parts, The Black Camel is noteworthy largely for historical, not aesthetic, reasons. As the earliest available appearance of Warner Oland in the role of Charlie Chan, it makes an interesting comparison with later entries in the series.
Start with that location photography. This is the only surviving Chan film of which I’m aware with such an extensive use of location work. Indeed, most of the films barely venture outdoors, much less to authentic locations. The fact that Camel is an early talkie makes that location work all the more intriguing, since the jumps in the audio quality attest to the primitive state of the technology. (That one of the characters, played by a young Robert Young, is a booster for Hawaiian tourism strongly suggests at least some promotional purpose was behind the production.)
This is also one of the few Chan films to be based on an Earl Derr Biggers novel, rather than simply using the Chan character. Those origins matter because in most of the films the identity of the villain is notoriously easy to guess, which is perhaps another way of saying that the scripts leave a lot to be desired. In Camel, on the other hand, the identity of the killer is a bit of a surprise, suggesting that by starting with a novel, the filmmakers were able to create a more complex and compelling mystery than other entries in the series.
The novelistic origins may also partially explain the differences in Chan’s character. In most of the films in the series, Chan is depicted as a genial, tolerant family man. He rarely has a bad word to say about anyone (aside from patronizing sons number one, two and three), and is never angry. In Camel, on the other hand, he makes jokes at the expense of his wife, clearly expresses eagerness to get back to work in order to escape his family and blows his top more than once. (He also makes mistakes, something ever rarer as the series progressed.)
If there is one aspect of the film that dates it, even more than the audio technology, it is its theatrical feel. Despite the extensive location photography, the bulk of the action, and certainly the majority of the “detection” scenes, sit listlessly on the screen as Chan and the other characters talk and talk and talk. While this dependence on dialog was common in early sound films, the later Chan films, whatever their literary limitations, are very sophisticated visually. The Black Camel thus remains a good example both of what happened to Hollywood when sound took over and of an edgier Chan than the polite pet he would eventually become.