Normally close up work for me is manual focus and manual focus only using Live View, DOF preview and 5x magnification.
But just occasionally we are set little challenges in how we capture an image.
It was under such circumstances yesterday that I found I needed to totally change my approach.
I had been watching many different butterflies in my wildlife garden and have generally always struggled to get anything half decent. They usually spot me coming from too far away and with the 100mm macro - my usual choice you need to get close.
So what to do?
Well I put together a combination of my 1Dmk3, 70-200f2.8 IS L, at 200mm Fl, with the 1.4 EFTC, plus a 20mm extension tube. This enabled me to get the minimum focus closer than the 1.4m minimum distance. I guess I could have used the 300f4 IS L as this also has a min. focus distance of 1.5m.
But why AI Servo?
My subject, a beautiful Orange Tip butterfly, showing its undersides was resting on some Shepherds Purse, of which there is plenty in the garden at the moment. However, there was quite a breeze and the thing was flapping about in the breeze. I tried to use the standard One Shot focus mode and I tried to manually focus but all the results were poor.
So I set the AI servo response to fastest in the Custom Function settings and set the AF to AI Servo mode. This way as the subject was moving back and forth the AF would continue to track.
However, it was important that I froze that movement as well so I needed to ensure a decent shutter speed, so I opted to ramp up to ISO800. This is a setting that the 1Dmk3 handles exceptionally well, provided you expose correctly.
The final tip for would be butterfly photographers is to manage your depth of field. When they are resting like this, go for the side on shot, get perpendicular to the subject as the DOF you need is at its lowest. You will be surprised how much aperture you need - this was taken at f10