In Java you can find a number of epic locations to experience and photograph. If you're reasonably fit and are up to climbing a slightly hazardous mountain path (due to slippery stones on a fairly steep trail), then Ijen Crater should definitely get on your short list.

After a strenuous walk up a wide path in the dark, you descend down a narrow zig-zagged trail to the bottom of the crater. As you enter the crater you'll enveloped from time to time by whiffs of rotten egg sulfur smells.

A few months ago my wife & I had opportunity to visit world-famous Mount Ijen crater in East Java, Indonesia.  This volcano has been featured on many documentaries & special TV broadcasts.  This is the place where famous French volcanologists Katia & Maurice Krafft dared to float on a highly acidic sulfur crater lake in a rubber raft. 

The Bromo-Tengger-Semeru National Park is like the Grand Canyon of Indonesia-in East Java. 

In pre-history there was an enormous volcano here. At some point it erupted leaving a massive crater 14 kilometers across.   In the middle of this ancient mega-crater are three newer volcanic craters—Mounts Bromo—still very active,  Batok & Kursi.  These triplet craters are surrounded by sea of sand that’s covered most mornings by a mysterious feeling blanket of fog.