At 4:53 an officer is on the coning tower of a U-boat and is looking through a pair of binoculars. All navies in WWII used binoculars and the German navy used binoculars that were not noticeably bigger than the ones used in the US Navy and Royal Navy of Great Britain, The Imperial Japanese navy did use binoculars that were noticeably larger than the ones used in other navies. Western sailors that noticed this often made racist comments about how near sited the Japanese Navy sailors were. Yet these over-sized binoculars worked better in the dark than the smaller binoculars, used in Western navies. In the night battles in the Solomon island area, in 1942 and 1943, the Japanese navy were sometimes able to detect Allied warships, before the Allies could detect the Japanese warships, using their primitive early war radar.
"The Shame of Savo: Anatomy of a Naval Disaster" by Bruce Loxton (1997)
http://ww2db.com/images/other_none940.jpg is a photo of an oversized Japanese Navy binocular