These pre-quake cards look west up California Street to Nob Hill and show no evidence of Fairmont Hotel construction (begun 1903).
The Fairmont Hotel was in the final stages of construction when the 1906 earthquake/fire struck. These images show the Fairmont but are pre-quake (no Sing Fat or Sing Chong). Fairmont Hotel shows the earthquake/fire damage and the reconstructed Fairmont.
Post-quake, the Hopkins Art Institute at California/Powell is gone and the new pagoda-towered Sing Fat and Sing Chong buildings are at California/Grant.
These cards look east from above Grant, showing cable cars on California and the Sing Fat / Sing Chong buildings. A Bay Bridge tower peeks out in the Piltz and Smith News cards.
Steve's SF postcard pages: