" It's fine to use your 100-400, nothing wrong with that lens but don't try to say the 400mm is not useful. The internet is full of incredible pictures taken by this lens. Perhaps it needs to be in the right hands. Search the internet for picture ...
This test came to the same conclusion as the Luminous Landscape test. A large number of 100/400L's were used to make sure results were accurate. The only lens or lens/extender combo that scored worse than the 100/400L was the 70/200 f2.8 with 2x. ht...
Sharpness is always an issue. When I hand-hold the 400 ƒ5.6,mostly for birds in-flight, I am shooting at 1/1600 - 1/2000 second. Sharpness is always an issue for nature shots. Here's a sample 400 ƒ5.6 hand-held shot. :
When I hand-hold the 400ƒ5.6 I am usually shooting in-flight birds at 1/1600 - 1/2000 second so I still achieve sharpness. I am always concerned about sharpness.
