These two very rare photographs showing the rough landscape of the lunar farside were taken during one of the orbital passes between orbits 18 and 30.
They were shot with the 80mm lens and the magazine 38/O used only in lunar orbit in the CM Columbia.

The first photograph looking south east shows pockmarked lands located north east of Crater Heaviside (latitude / longitude: 6° S / 173° E).

The second photograph looking south west shows the 160-km Crater Keeler with the 70-km Crater Stratton in the foreground (latitude / longitude: 6° S / 164° E).

From the mission transcript during orbit 23:

121:10:47 Public Affairs (Mission Control): This is Apollo Control. Spacecraft Columbia has gone behind the Moon on the 23rd lunar revolution. [...] Not since Adam has any human known such solitude as Mike Collins is experiencing during the 47 minutes of each lunar revolution when he’s behind the Moon with no one to talk to except his tape recorder aboard Columbia. While he waits for his comrades to soar with Eagle from Tranquility Base and rejoin him for the trip back to Earth, Collins, with the help of Flight Controllers here in Mission Control Center has kept the Command Module’s system going “pocketa-pocketa-pocketa”. At 121 hours, 12 minutes Ground Elapsed Time, this is Apollo Control.