The photographic community is familiar with Sigma lenses and I never gave the name much thought until October 8th when I assisted Evergreen Shipping's EVER SIGMA (ex HATSU SIGMA) into its berth at Pierce County Terminal, Tacoma, Washington. I have always known about Sigma lenses and I have assisted this ship in many time, but never gave it a thought, i.e. put 2+2 together, until I purchased a Sigma 10-20 f3.5 for my D90.
So, what is the meaning of the word "Sigma"?

So, what is the meaning of the word "Sigma"?
