Hi Brett,


I think I still hear that horse breathing, let me beat him a little more!


If you need 300mm for outdoor sports then also consider the 300mm f/4L IS it is not weather sealed but it is better than the the 70-200mm f/2.8L +1.4X extender at 280mm. (see ISO Crops below)


http://www.The-Digital-Picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=111&Camera=453&Sample=0&am p;FLI=0&API=0&LensComp=242&CameraComp= 453&SampleComp=0&FLIComp=5&APIComp=0


Here is for the 300mm f/4L IS compared to the 70-200mm f/2.8L IS + 1.4X which is better than the non-IS version, but still not as good as the 300mm f/4L IS.


http://www.The-Digital-Picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=111&Camera=453&Sample=0&am p;FLI=0&API=0&LensComp=103&CameraComp= 453&SampleComp=0&FLIComp=5&APIComp=0


Of course you loose the flexibility of the 70-200mm zoom, but you gain quality on the long end.


Here is the 300mm f/4L IS vs. the 70-200mm f/2.8L IS II + 1.4X extender.


http://www.The-Digital-Picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=111&Camera=453&Sample=0&am p;FLI=0&API=0&LensComp=687&CameraComp= 453&SampleComp=0&FLIComp=4&APIComp=0





If you need the 300mm most of the time then the 300mm f/4L would be the way to go. If the 70-200mm f/4L that you own would work for you indoors then you can keep it, but I think the f/4 is really pushing it for indoor use unless you are using strobes.


If you need the 70-200mm and the ability to use the 1.4X extender frequently, then I would try to save up for the 70-200mm f/2.8L IS II, because if you get this lens then it will amost feel like your getting 2 lenses for the price of one. By that, I mean that the version II is awesome from 70-200mm and it's also very acceptable at 280mm f/4L IS II with the 1.4x. Also as a bonus, I think the version II lens is even acceptable @ 400mm f/5.6 when using the 2X extender for limited use.


If you would like a compromise then the 70-200mm f/2.8L IS may be a compromise. I also realize that outdoor sports will be over in about 2 months, so this may influence your decision.


You really don't need IS for sports, but the IS lenses in this case are better lenses.


You need an f/2.8 lens if you would like to add an extender.


Weather sealing helps in a light rain, but if I were to shoot a game outside in the rain then I would use a rain cover, even if the lens was weather sealed.





Rich