Sx70 hs in low light the evf and lcd are terrible. The evf is very grainy and the lcd has light bleed purple or red streaks of light bleeding across the screen but in good lighting both are fine also near fluorescent lighting the lcd flickers is this normal especially the low light lcd issues?
Iso 800. Definitely not a camera for low light use as the evf and lcd make composing the scene difficult.
welcome to the Forum, Chris. Have you looked at your menu settings, as Ray said your ISO may too high. what are your file size settings