If you’re still shooting with a 35mm camera, especially one that automatically sets the ASA rating based on the DX label of the film cartridge, you can still push or pull your exposure even if your camera won’t let you manually set the ASA rating!

Check this out. Porter’s Camera Store sells DX labels for popular ASA ratings like 40, 100, 125, 200, 800, 1600, and 3200. So you could load your 35mm point-n-shoot with some Tri-X ASA 400, slap one of these labels on your film cartridge, and fool your camera into working at an EI of 1600.