Is it better to boost the ISO, or underexpose and push in RAW conversion?
Note that you may want to read about the the meaning of ISO for digital cameras, and why noise increases with ISO, before continuing with this answer. Results will vary from camera to camera, but manufacturers typically choose the best combination of analog amplification and digital bit shifting, so you are unlikely to get less noise if you underexpose and push. However, if you can verify that your camera is simply bit shifting, then you might prefer to underexpose and push since this gives you greater flexibility to recover from overexposure by giving you the option of pushing less than one stop if you decide later that one stop was too much.
