While digiKam won't rival dedicated software for tethered shooting, you can use the application's Import interface to trigger the connected camera and instantly fetch photos from it. This functionality can come in handy when you want to have an instant preview of photos you take on a large screen.
This is a companion discussion topic for the original entry at https://www.digikam.org/news/2012-03-12_tethered_shooting_with_digikam/