Hello from Greece,
I'm a professional wildlife photographer, have just left South Luangwa, so I would like to share my experience with casual travellers and of course photographers as well.
South Luangwa national park is a vast jungle type- forest divided from north to south by the mighty Luangwa river. It is a Leopard fan paradise, cause as I discovered myself the density of the spotted cat per square mile is unsurpassed by any African national park I know!! The variety of mammal and bird life is staggering, although a lot of times well hiden under the thick and dense undergrowth!
Game drives (for the average tourist) last from 6-10am and from 4-8pm, although the park is open the whole day for anyone wishing to stay inside and do game drives all day long. The temperature (I can only speak for dry season) is a bit of an issue, since it is very chilly early morning, becomes quite hot around midday, and then again chilly and cold again during the night.
There are no huge lodges in the area, just tented camps, some expensive and luxurious, some basic, suited for the budget traveller. They all are positioned (side by side) by the banks of Luangwa river so as you can imagine, all of them provide spectacular view to the river and wildlife!
The park is not heavily crowded (just like the more "glamorous" parks of east Africa), which means that most of the times you do your game drives alone, without any other vehicle in sight. If there is an interesting scene though (leopard on a tree, lions with a kill) news spread out quickly and vehicles from all destinations come and gather!
Light quality (this information probably referres to photographers!) is quite good although not matching the standards of parks such as the Serengeti or Masai Mara...let me explain. Light is soft and warm, ideal for wildlife photography only from 7am to 9am in the morning and from 3pm to 6pm in the afternnon. After 9am the sun is already high in the sky!!!, providing harsh unsitable light...that is the time to leave open plains (which are very few anyway) and focus on densed forest areas where the sun's harsh light is difused by the forest canopy.
Night games are also most welcomed (they last from 6pm to 8pm), they are for free and very interesting due to the fact that all vehicles in the valley are totally opened, and that predators (mainly leopards) start moving, showing some activity by that time!!
In summary South Luangwa is a spectacular game park, ideal for anyone wishing to see a leopard by any mean. Spotting and taking photos of animals is more difficult though than other well known parks, due to the dense undrgrowth.
Last but not least to mention are the wonderful sunsets where the sun literally "melts" inside Luangwa river....if you are THAT lucky to witness by that time Elephant herds crossing, it will be an experience nver to be forgotten!