The main reason to use custom "Lens-Sensor Recipes" (& LUTs) is that every lens sends light to a sensor differently. Some sensors like sharp lenses (especially those with an optical low-pass filter) and some don't like a lot of sharpness. Some sensors love lots of color saturation, yet some can only take a little. Before I knew this, I was searching (for years) to find the perfect lens-sensor combo...until I realized that they need CUSTOM SETTINGS (now called Recipes).