Most of the time it depends on where I am at shooting. If I can work it out I use the 50mm F1.8 or if forced I will use the 28-75 F2.8. Most of the ones I have shot have had some decent lighting but there have been a couple that were low light. The lowest I have shot was with a 50mm F1.2 but if the lighting is real real bad then yes I will pull out the 580ex but I hate doing it.