ok, but they are flying fast, changing altitude alot, doing spins, flying at night, landing on ships, etc. you would figure during all those flight hours seeing something out of focus would be regular. if you take pictures how long does it take to go out of focus? you run into it really quickly.
with all those pilots and all those things you would figure it would be in a power point under 'weird stuff not to get confused by' slide. or the 'things you might not know about your plane because their a little different then what you are used to with normal equipment'. I figured this would show up on a manual slide project sometime around 1960 in vietnam and be standard since then, since they had the crappiest night vision with tons of problems back then and were always doing stuff at night.
'your target might look like a triangle because....'
'sometimes you see a triangle on your screen and this can mean you should..."
'we had an incident where a pilot showed up to locartion xyz during a night time support operation and did not destroy the target because he was confused by its triangular appearance, this is normal because... and can be resolved by...'
i mean it seems pretty fucking important to know when you should change the focus..........