From [NASA][1]:

> AS11-40-5886 (OF300) ( 1016k or 155k )
>
>    110:31:47 Rightward of 5885. This frame from Buzz's plus-Z pan is the only good Hasselblad picture of Neil on the lunar surface. Eric Nelson has produced an enhance version ( 320k ) of the portion of the image that includes the flag, the SWC, and Neil at the MESA. A closer detail ( 195k ) shows Neil packing the bulk sample with an open rockbox on the MESA table. See the discussion following [110:31:47][2].

Clicking on provides:

> For many years after the mission, NASA contended that Buzz never had the camera and, consequently, never took a picture of Neil. In fact, frame 5886 from Buzz's plus-Z pan shows Neil at the MESA. An extensive discussion with Neil and Buzz about this photo and about NASA's mis-conceptions about who had the camera at this time is linked below.
>
> A thorough discussion of AS11-40-5886 is linked [here][3]

Where we find:

> In late 1986 I was informed by Neil Armstrong's office that he believed the photo of himself in the background lay between frames 5875-5901. In May 1987 after studying a copy of the 'Apollo 11 70mm Photographic catalog' sent to him by Lee Saegesser (NASA HQ History Office) Armstrong confirmed to me that 5886 was the one.


  [1]: https://www.hq.nasa.gov/alsj/a11/images11.html#Mag40
  [2]: https://www.hq.nasa.gov/alsj/a11/a11.mobility.html#1103147
  [3]: https://www.hq.nasa.gov/alsj/a11/a11.5886.html