This is an interesting photo, as it shows a "Leichte Feldkanone C/73", 8 cm caliber. According to v.Lettow – Vorbeck's books, the German Schutztruppe had two of these outdated guns in 1914. Since about 1900 the two guns had decorated the lawn in front of the government house in Daressalam. The empty shells were planted around the edge of that lawn, while the impact fuses were found in a dark warehouse corner. Lacking any artillery except some light mountain guns, the 2 old cannons were cleaned up and pressed into service. The shells were unearthed, wound with copper wire guide rings and refilled with blackpowder . Both guns were used effectively in November 1914 to repel an abortive landing of about 8000 British – Indian troops near Tanga. The outcome of this landing allowed the Schutztruppe to expand and resupply, as the British forces left behind enough modern Lee –Enfields to equip more than 3 companies, 16 machine guns, 600 000 cartridges and sundry other equipment. The Schutztruppe could field only about 1000 men against the numericallly superior empire forces, most of them freshly recruited Askaris.
In 1914 the peacetime Schutztruppe had 14 companies, 216 Europeans and 2540 Askaris. Three companies were just rearmed with new M98a Mauser carbines, while the rest still had the old blackpowder, single shot M71. Four new companies, numbers 15 to 18, were formed just after war was declared August 1914. Many Germans then living in East Africa entered service again. So the maximum force during the war numbered about 3000 Europeans and 11 000 native Askaris. During the war two blockade runners, "Rubens" 1915 and "Marie" 1916, brought in supplies, among them 3500 8mm rifles and carbines, two 6cm Marine landing guns and a total of 8 more machine guns.
This photo apparently shows one of those old 6cm landing guns and one of the Maxim MG 08 on naval landing carriage, together with M88 carbines, brought in by the "Rubens".