If you don't know what's the best aperture for sharpest photos in certain settings and you only shoot wide open then you may be doing it wrong if the goal is sharp photos. Even though shooting at F/1.2 or 1.4 is pretty cool to look at when done right it isn't the sharpest tho, it is the fastest. For most good and well crafted lenses the area is between 2.8 to maybe f/4 (2.8 for the 1.4, maybe). For my lens personally I need to be at f/14 with miniumum items in the background. That is my settings for the aperture when I'm taking most of my shots of myself and for candids I stay in between f/9 to f/13 and I do use flash when shooting. I learned this when shooting multiple items at different apertures.