My current equipment:
Body: 50D, Lenses: 10-22, 24-105, 70-200 f/4 IS.
My subjects:
- Bicycling race photograpy (www.bkingfoto.com) pays some bills.
- Family portraits: 6 month old baby girl Julia Anne (www.bkingfoto.com/Julia)
- Travel photography
While I am generally very happy with the 24-105 and the 70-200 I have, I am considering if I would be significantly better off to have f/2.8 glass for the general purpose and 70-200 lenses. I could probably financially justify replacing the 24-105 with either the EF-S 17-55 f/2.8 IS or the 24-70 f/2.8, and replacing my 70-200 f/4 IS with the non-IS f/2.8 version.
Here is my analysis:
Pros: The 2.8 lenses would improve the autofocus for the fast action shots for bike racing, and would be better for available light family portraits of my little girl.
Cons: Cost, hassle, giving up IS, and the physical size of the 70-200 2.8 is a negative for me for a travel lens. I really like that my entire kit fits nicely in a Slingshot 200 bag!
I know a future body will have a better focus system that should benefit my race photography, on the other hand, no matter what body the future brings my way, I assume the focusing would always benefit from having faster glass.