Also, what module are they in when the photo was taken...
The lunar module.
...and what are the approximate dimensions of the cabin?
While standing at the controls (the closest you can get) the window is about an arm's length.
Is that a landing strut we can see, or some other type of equipment?
I venture some sort of equipment, but it may also be the window frame. Here is a lower-resolution copy which is nevertheless scanned with a higher gamma value. The feature in question obviously lies in front of the other features, supporting the contention that it's a reflection on the glass.
http://www.lpi.usra.edu/resources/ap.../?AS11-40-5844
...If the cabin is smaller than half that distance, then the reflection theory doesn't wash.
But depth of field also depends on the characteristics of the lens. Do you know the depth-of-field characteristics of the Zeiss Biogon? Have you ever used that lens?