Catching the vital moment
We hear so many moans from people who should know better about the lack of PDAF in the current generation of m43 cameras. I will try to explain why I think it is often unnecessary.
Rapid autofocus is widely recognised as being important for shooting fast moving action such as sports and small children. The only sport that I currently shoot is rugby union football. This photo was published in both print and on the newspaper's website:
(Oops sorry they appear to have messed around with their URLs. You can find it quite easily by going to the newspaper's home page, then the sport menu and select rugby, looking for players in blue and white shirts.)
The photo was taken from the touchline using a GH2 with 14-140mm lens set to 25mm focal length. In order to catch the vital moment when the player running with the ball is about to be tackled, I needed to be sure of at least 5 things:
- that the shutter speed was short enough to freeze the action.
- that the aperture was stopped down far enough to give me adequate depth of focus.
- that the ISO was not too high.
- that the camera was responsive enough to help me catch the vital moment.
- that I knew enough about the game to know when to release that shutter. (I did play the game for nearly 30 years, ending up playing for the good guys here in blue and white.)
My technique was to shoot with the GH2 in S mode, selecting a shutter speed of 1/1600 second for this image. I find that you need exposures shorter than 1/1000 sec to freeze action in this sport. I use the smallest central focus spot, half press the shutter, and keep the camera glued to my eye until I judge the moment right to release the shutter. I do this at an AF-S setting and find that it only takes a little practice to perfect this technique.
This image was taken at 1/1600, f4.7 and ISO320.
Of course by the time that the newspaper has mangled it for print and downsampled it for their website it appears nothing like as sharp as the original.
The bottom line is that sports shooting with AF-S in S mode on the GH2 is an easily learned technique.