Just started to wonder. Taking an example of a 300mm f2.8 vs 300mm f4 lens. Are there much reasons for the 2.8 being more desirable?
Its heavy, and when shooting animals/birds you do not need the 2.8. I can only think of indoor events like fashion shows, etc where it might be more useful. Even then I may use flash which negates the 2.8. Don't tell me the IQ of 2.8 lenses are consistently better than f4 lens? Cannot be right?
Hmm... am I missing anything?