I'm always scoping out good spots for shooting when visiting new cities and have been doing a lot of reading on the best spot in San Francisco to get a great cityscape photograph. I'd shot from Baker Beach, the Marin headlands and this shot from the Oakland Hills in the East Bay but wanted something that showed more of the downtown area and the bay in its entirety.
I had gone backwards and forwards over the Bay Bridge a number of times passing Treasure Island but, had never thought to stop there as had always been in a rush to get to the East Bay or back to the City. The artificial island was originally a military base and only has a tiny exit off the I80 freeway when crossing the bridge - it's very easy to miss!! Here's a screeenshot so you you locate it - the grey pin is where I eventually ended up standing to shoot a panorama:
However, I cannot recommend visiting the Island highly enough. It offers spectacular views back onto the city spanning all the way from the Marin Headlands, the Golden Gate Bridge, Alcatraz, Downtown and the Bay Bridge - you can literally see everything! Unlike many scenic spots similar in other cities I've visited, at Treasure Island it's easy to park right at the sea front and seemed relatively safe. I was able to wander up and down the shoreline with my tripod, unobstructed and not bothered by any pesky security guards.
I arrived about half an hour before sunset and captured a few frames as the sun spectacularly went down behind the Golden Gate Bridge. However, what I really wanted to capture was 'blue hour' - that magical time about twenty minutes after the sun sets; by far and away my favourite time to shoot a city - as the lights begin to come on, illuminating the city and creating a great contrast. Below is a 12 stitch photo panoramic I created which shows a view stretching from the Bay Bridge, across the Financial District and includes The Ferry Building and Coit Tower.
With San Francisco's constantly changing weather conditions, I would encourage multiple trips as everytime you visit, you will get a different set of shots. This really is a hidden treasure!