Following the trans Earth injection burn over the lunar farside, the crew witnessed and photographed through the 80mm lens a fantastic view (see mission transcript) of the receding Moon from a perspective not visible from Earth.
From the mission transcript after trans Earth injection:
137:46:27 Engle (Mission Control):
Hello, Apollo 10. This is Houston. How did the burn go?
Roger, Houston. We are returning to the Earth. Over.
Glad to have you on the way back home, 10.
Roger. The burn was absolutely beautiful and Gene-o has a report, and we have a fantastic view of the Moon now. Over. [...]
We’re taking all kinds of pictures. I’ve got the tubes, Gene-o has the
equence camera, and John has the Hasselblad. We’re getting all this documented. [...]
I thought it was a fantastic view leaving the Earth, but it is going to be even more fantastic one leaving the Moon here and heading back to the good old Earth. [...]
In fact, looking straight ahead, just now coming into view, even though we’re really starting to climb out from it - In fact, I can finally see the whole Moon right in the hatch window. [...]
Boy, you can’t believe this rate of climb. It looks like we’re just going out just vertically. Just beautiful. It would scare the heck out of you if you came at this angle, but maybe it was just because we came in the dark and didn’t see the thing. Over. [...]
Joe, this is incredible. That thing [the Moon] is getting rounder and rounder and rounder and smaller all the time.
138:02:40 Engle (Mission Control):
Rog, Gene-o. Understand.
The real show is on the inside here; it’s like three monkeys in a string pod. [...]
Hey, Joe, the Moon is almost small enough now where I can see the whole thing from the top, one corner of my forward window to the other corner of my forward window. [...]
You guys are really hauling the mail out there. [...]
Hey, Joe, down at 9 miles [16.7 km] has to be exciting, but this has got to be unbelievable. The wind - the Moon now is well within the boundaries of my forward rendezvous window. [...]
See what I mean about size, Joe. It just about fills up, roundwise, right smack in the hatch window. Boy, and is this a full Moon, I’ll tell you.
You’re just about 1,400 [nautical] miles [2,600 km] out now, Gene.