9th December 2003, 02:27 PM
Tracking birds or fast moving objects
Do you usually:
1. Focus lock on using Multi-AF point and AI Servo (Continuous) using a lower end of the zoom 70mm in (eg 70-200mm lens) and then zoom into 200mm and shoot.
2. Prefocus at a certain point (using single shot mode) . Sometimes, a blue sky is what you have, then you'll have a problem where to pre-focus.
9th December 2003, 04:16 PM
i would use the continuous focus mode for most circumstances. but if enough research of the pattern of bird flight path and predictions can be made, one can use the prefocus method.... if sky is the background and af doesnt work, use manual focus.
9th December 2003, 04:33 PM
use the Manual focussing...the human eye and hand is so much faster than the machine.
9th December 2003, 05:45 PM
Wah, you must be superman. Manual focus is almost impossible on moving subjects, esp those moving toward/away from the camera, and also esp with shallow DOF.
Originally Posted by sojourn88
This is one instance where it pays to know the exact depth of field. If it's too narrow for the application (eg trying to get sharply focussed eyes on a 100mm at f2.0 from a distance of ~1.5m, moving target), i would say forget it and just use wide area AF.
If you prefocus, i think you MUST know your DOF for the given aperture, focal length and subject distance. Carry a DOF calculator or a cheat sheet with the DOF tabulated.