If you are driving up to Leh, you should pretty much carry whatever you might require for the journey. Leh itself is quite a large town where almost anything you might require is available. At least the basic stuff. Carry enough film, batteries, etc. as the entire journey there gives you a huge number of photo opportunities and almost no chance to replenish your raw material.

Food is available along the way but since the places to eat are extremely spaced out, it is advisable to carry snacks and bottled water with you. A favourite with most travellers in the area are dry fruits like almonds, cashewnuts,etc.

Definitely carry any medicine that you specifically use.

A pair of binoculars are often missed when faced with scenery of such vastness.

A torch is always a handy item to add to your luggage.

A skin moisturiser and lip balm as the climate tends to get extremely dry at times. For the same reason it is also advisable to take along some rehydration tablets or powder.

The sun can get extremely strong at times and people with sensitive eyes are advised to take along a sunshade and dark glasses. Sunscreen for the skin is also advisable for people with sensitive skins.

If you are planning on camping around Ladakh, you have the options of either carrying your own equipment along with you or hiring it in Leh. There are many tour operators and shops that loan out such equipment.

It is not a necessity but it would be a good idea to carry along one small can of oxygen.