Translation:I put up the umbrella.
We'd put up a picture, or put up a tent, but it's always something we're no longer holding. Even for a guest, by "put up" we mean we give them a place to stay and then let them be. More formally we "hold erect". I think the Japanese doesn't meant that so much as to raise from the lowered position though. It could be out to the side or up. It's even said Americans always waving their hands about even in confined places like on trains makes them visibly nervous . . .
I would put up an umbrella if it was a big beach one. Putting up a regular umbrella to me might mean just raising it. Opening would be the act of unfurling it, regardless of whether I was holding it up in the air or not. I guess the question is whether Japanese has all those meanings or if there are specific words with those meanings.
"I put up the umbrella" is just fine to me (baby boomer raised in Vancouver Canada); if I'm standing at a bus stop when it starts to rain, and I have an umbrella, I'll put it up. Could someone please confirm whether "kasa o sashimasu" also includes the sense of putting up a patio umbrella?
To me, "opening the umbrella" is literally pushing the slide up and unfolding it, whereas "putting up the umbrella" is the whole set of actions: unlocking it, pushing the slide up to unfold it, and raising it over my head to the traditional position. One might open an umbrella (to dry it, to show off the pattern) without putting it up (to carry as a rain defense).
This is an odd translation. It should really be either "I will open (or put up) my umbrella" as masu form is usually used to indicate intent, or simply "to open (or put up) an umbrella" which is a sentence that would generally only be used in a textbook definition, or something of the sort. The sentence "I put up the umbrella" seems to be past tense to me which should translate to "傘をさしました", and even if there is some technicality I am unaware of, it still sounds very unnatural.