I sold my Canon 100-400mm lens a few months ago because I was not getting very many sharp images with it. I was intrigued when I heard about the Canon 70-300 so I got a hold of one for a few days and borrowed a friend’s 100-400. I found that there was not much difference in IQ between the two lens. The 70-300 was noticeably lighter and seemed to focus faster than the 100-400. IS was faster too. Another advantage was in its macro capabilities and ability to shoot as close as 47 inches.
These were shot at f/5.0 and 200mm:
I just returned from an excellent adventure in Northern Spain hiking the Picos de Europa for ten days. It was a small group of which almost half were advanced to professional photographers.
One of the photographers had just purchased the 70-300mm for the trip. A great deal of what we shot included butterflies, various insects and orchids of the region. Since there was frequently need for many of us to shoot the same subject, the close focusing range of the 70-300mm was an advantage him a space that wasn’t occupied by other macro shooters who tended to be in closer.
He generally was not please with his bird shots due to insufficient reach and low light and 300mm was a challenge. This combination of shortcomings which didn’t allow enough of the bird to fill the focusing point caused seeking between obstructing branches and leaves. His comments about the weight compared to the 100-400 was a blessing and the macro shots done at 4 ft had a good percentage of keepers. He said that overall he was pleased with the lens.
Here are some more shots I made with this lens during the time Canon CPS let me borrow it: