I lived in CA for 10 years, but I wouldn't know where to begin to answer this. There's just TOO much there.
Unless you're going to be there for six or eight weeks, my best suggestion is to limit your appetite. The distances are great, and if you try to do too much, you'll be frustrated with spending so much time just sitting in a car getting from one place to another.
The landscape/wildlife opportunities are endless and almost everywhere. Do some good planning, again, keeping distances (travel times) in mind.
Yes, pretty much exactly.
California is something like the world's 6th largest economy, geographically larger than most European countries. In some seasons you can drive between sun bathing on the beach to snow skiing in the mountains in just a few hours.
Micro climates abound even within single counties.
Super rich in Beverly Hills and elsewhere, super powerful in Sacramento. Poverty and homelessness on the streets of most cities.
High crime areas in all the big cities especially Stockton, Oakland, Salinas and L.A., keep to your own business if you wander in to those areas, get to somewhere nicer as quick as you can and you'll be fine, don't linger, especially don't stare. These are not places for tourists to practice street candids.
Busy busy port cities in L.A. and Oakland, huge agricultural vistas in the valleys and along the coast.
Gilroy, the Garlic Capital, Castroville, the Artichoke Capital. There's a brussel sprouts capital too, I forget where.
Watsonville STRAWBERRIES!!!! World renowned and deservedly so. Seasonally availability throughout the U.S. varies. Watsonville also bills itself as Apple City, but I'm originally from Michigan where I learned apples are best following the first frost which Watsonville rarely gets. I'm meh about Watsonville apples.
Incredible beaches all along the coast with about as much variety as everything else. HUGE world class surf at Mavericks near Half Moon Bay, some really great surf photographs come from there. Good surfing along a lot of the Santa Cruz country shoreline, lots of good surf in Southern California too.
Mountains, gorgeous mountains. Really really BIG and old trees in the redwood forests.
Hollywood and the movie/tv industry.
Tesla builds cars.
Steinbeck country from Salinas/Monterey through Santa Clara/San Francisco, Jack London country from Santa Clara though Sacramento especially the East Bay (of S.F. Bay).
Gold Mining ghost towns in the Sierras.
Big Sur, Point Reyes.
Diversity. In my opinion, California's best feature. America's claim as a melting pot exists and is readily apparent daily in many places in California. Every nationality, ethnicity and culture is represented and all get along with each other (mostly) quite well. China Towns, Mexican Towns, Little Saigons and so forth abound. Lots of photo ops here but do use caution, gangs there too.
Great college campuses at U.C. Berkeley, Stanford in Palo Alto, U.C. Santa Cruz and elsewhere.
You can see the Hoover Tower at Stanford from the Campanile at Berkeley and vice versa.
Sweeping ocean vistas at the U.C.S.C. campus.
Epic traffic jams 24/7 around L.A. and beyond, most especially the 405, bring lots of patience, water, fuel and a working cell phone.
The I-280 freeway between San Jose and San Francisco is billed as "the World's Most Beautiful Freeway" to which I'll say maybe, but I figure that's a tough claim to make. It is a pretty drive, far preferable to the 101 for similar destinations. Traffic jams on both ends during commute times, even then, nothing like the usual and continuous jams around L.A..
California Highway 1 along the coast is epic, just epic. A tourist could spend an entire trip just on Highway 1.
San Francisco. I don't know where to start about San Francisco except to say, never call it 'Frisco while there nor anywhere near.
San Francisco is one of those places that I expect will always tug at a piece of my heart (J.J. reference), it is my favorite city, a real stand out.
Public transport is excellent there, preferable to driving and especially parking.
Most tourists wouldn't think of missing the cable cars and for good reason, don't miss them. The restored 1940's era trolley cars are pretty cool, buses go everywhere else, cabs abound.
So many places to go, things to see and do, check http://sfgate.com
, the San Francisco Chronicle's web site for events, tons of other on-line resources about S.F. too.
Several, long established camera shops in S.F., but I've never been to any so cannot comment. A lot of hole in the wall electronics shops along Market, I wouldn't shop there but there may well be photo ops there.
I'm only familiar with a few camera shops, all in the "Central" California area.
Keeble & Shuchat in Palo Alto is rather impressive for both size and inventory, I gather it's somewhat like a mini B&H or Adorama in N.Y. but having never been to either of those can't say for sure. Multi floor buildings on both sides of the street, a literal forest of tripods on display in the ground floor main room of the main building. Sadly, staff seems a little rushed though knowledgeable about their products. http://kspphoto.com/
In sleepy little Soquel on the Monterey Bay is the one man show that is the Monterey Bay Photo Mart's Richard. A funky, dusty place with lots of film, chemicals, darkroom stuff and the like, I did buy my (now old) Nikon D80 there on the first day it was released. It's a mix of old and new. If just to buy, best to call first. I'm not seeing a web site, here's a google thing https://www.google.com/#q=monterey%20bay%20photo%20mart&safe=off
Richard's speech is a little hard to understand sometimes, he is definitely worth listening to.
Not far away in Capitola and Santa Cruz is the world renowned Bay Photo Lab. Not at all a gear shop, most definitely a top notch photo print shop. http://www.bayphoto.com/
Pardee's in Sacramento http://www.pardeescameras.com/
is pretty much what an old school, local and independent camera store can and should be. Low pressure, friendly and knowledgeable staff, prices vary from fair to competitive.
I do want to give San Jose Camera and Video (in San Jose) a mention, mostly to suggest you google some reviews and that's all I choose to say about that place. .