2) Don’t Fear the ISO
Once you have selected the proper shutter speed and aperture, your exposure may still be too dark. If so, the solution would be to raise your ISO: a very effective method of perfecting the exposure.
Despite this, I talk to countless photography students who are afraid to adjust it. They fear the digital noise that occurs with extremely high ISOs.
The truth is, cameras on the market today can be used at extraordinarily high ISOs, creating just a fraction of the noise that previous models exhibited. Couple this with a bit of noise reduction available in most image editing programs and you have a non-issue.
3) Simplify the Focus
Like all moving subjects, using the center autofocus option along with the AI Servo mode will provide the best results. The outer points are difficult to adjust quickly and are not as sensitive as the middle point.
Keep your active focus area on the bird with your shutter button held halfway down. This enables the AI Servo mode to track the subject and automatically adjust the focus.
It works for subjects passing left to right as well as those heading directly towards you. Rather than using “One Shot” mode, select the continuous high speed burst option to capture more frames per second.