This blog post was brought about following an online discussion with a fellow photographer who was insistent that the best and most reliable method for photographing bird in flight (bif) was to use shutter priority with auto iso. Whilst in theory this sounds like a reasonable idea it is In fact a terrible strategy which will frequently produce images which lack their full potential and leave you feeling disappointed. The main reason for this is that it is generally desirable to keep the iso as low as possible to prevent unwanted noise and thus preserving the fine detail of your image. When using auto iso despite what the manufacturers say the camera will invariably lift the iso far higher than what is actually required.
What I would suggest is to actually shoot in aperture priority. I normally shoot wide open, however if your lens is not sharp wide open it will need to be stopped down. From here I keep an eye on the shutter speed and control this by manually adjusting the iso. My baseline is to leave it at Iso 400 then adjust this up or down depending on light levels and the presenting situation.
Back Button Focus - AF-On
If you are not doing this already I would say this is probably the single most important setting that will improve your bif photography. Basically what this function does is separate the focus from the shutter. This will allow you to hold your focus with the back button as you track the bird through the sky giving you the added control of being able to fire off short bursts from the shutter button. It might feel alien at first but after a little practice you will be left wondering how you ever manged without it.
Perhaps obviously continuous auto focus (Al servo / AF-C) should be selected so it tracks the bird as it fly’s through your field of vision.
Drive mode should be set to continuous. I opt to set mine to the hi speed and shoot in short bursts of three or four frames. However there is some research that suggests the slower continuous mode will deliver a better ratio of keepers.
When selecting auto focus points for BIF it is certainly a case of less is more. I settle for using the center point with the surrounding ring of 8 points. This is because that the more points that are selected and the more work the camera has to do. Consequently this means the focus points become less accurate. This seems particularly apparent with larger species as critical focus can be lost with erratic movement or even wing beats.
When it comes to metering I choose center weighted. Whilst this mode evaluates the whole frame it puts emphasis on the center of the frame. This is perfect for bird in flight as this will hopefully be where your subject is positioned in the viewfinder and ensures your image is properly exposed.