I do mostly weddings and engagements. After reading reviews (and many hours of frustration with the camera) I found out it is because of my lens I have now. I have a tamron 28-200 and a sigma 18-200. I have had wonderful pictures from these lenses on my nikon d50 but not with the D300. So.... what lenses should I invest in for my D300? When I shoot I do lots of quick and candid shots. So please help this frustrated photographer who is learning. I want to use my D300 so much but everything is always so dark! Thanks! Happy shooting!