Pictures of the past

Among the slides I picked up a few weeks ago was a red-bordered, glass-covered Kodachrome (I think) of some random people.I'm guessing '50s or very early '50s'. Based on the out-of-focus it would be a fast-ish lens. SLRs wouldn't have been around in force until the Nikon F in 1959.My guess was the Leica Summitar f/1.5 stopped down a bit. Further guessing: Leica M3 + Summitar 50mm @ f/4 @ 1/60s.But the people. Three are looking at the camera; one away.Dress shirts with stuff in them: engineers.Hedges: weekend away from the office.A pair of couples: Grandparents?So many stories.Unknown.