50/1.6=31.25mm, so I guess you want a 35mm or perhaps a 28mm lens.


Based on the exposure triangle, you have three options in low light: use a slower shutter speed (usually limited by handholdability and/or subject motion), raise the ISO (hardware limited by camera), or use a larger aperture. So, I guess you want the Canon 35mm f/1.4.


Since you usually get what you pay for, more expensive lenses are usually better. Since the 35/1.4 is the most expensive prime lens and has the largest aperture, I suspect it