Thanks for the chart Brant. I'll be using the MK IV as my main body and if I need a 2nd setup then I will put a 24-70mm or 70-200mm on my 7D.


I feel confident about what focal lengths I need for sports because I'm dealing with a certain sized field. However, when it comes to BIF and wildlife there aren't any rules. You could have a bird near or far, or high up in the air. So, I think that's where I'm not sure what I want or need. I think the 600mm shots below look nice, but I think they may have been better if the bird had some more room around the frame and room to fly into.





1D MKIV: 300mm f/2.8L IS + 2X @600mm f/5.6 1/1250sec ISO 320



















Then I had some closer ones yesterday:


MK IV: 300mm f/2.8L IS @300mm f/6.3 1/500sec. ISO 400






Rich