Peter:
I hope you enjoy your trip to the US.
If you are flying into San Francisco, definitely spend a few days
there. It is a lovely city. You might also want to drive down the
coast to Monterrey, or to the wine country of Napa/Sonoma. Both are
scenic and highly photogenic.
By all means, go to Yosemite. It is one of the best places on earth for
a nature lover and for a photographer. As for the bears, never carry
any food, candy, gum, or cosmetics on your person or in your car. Even
an old empty food wrapper may cause them to rip open a car. Mariposa is
near Yosemite, and has many huge sequoia trees.
After Yosemite, the Grand Canyon (especially the North Rim) and Bryce
Canyon are my favorites in the Southwest. Mesa Verde is also great for
photographic opportunities.
As a Slovak-American, I welcome you to the US. I hope someday to see
the High Tatras.
Where do you live? My mother's parents came from Senica, in the western
part of the country. My father's parents were Rusyns from near
Mukachevo, which was taken into Ukraine by the Soviets during WW II.
In any event, have a great trip, and enjoy yourself.
Dan M