Zoom lenses foreshorten distance between subjects.
eg This picture of two aircraft in the stack for Heathrow
The DHL is at FL90 and the JAL at FL100.
(For non-pilots/non-ATC: 1000' vertical separation.)
There is also 1000' vertical separation between these two:
(Picture originally posted in the ATC forum by PPRuNe Radar)
Heliport