Hier een stukje in 't Engels' van flickr:
"Let me explain why using AF-On is so much better than using the shutter button for both focusing and shooting.
If you are using the shutter button to both focus track and shoot, a split second passes from the moment you obtain focus and the moment you shoot the picture. Even in this split second, a fast moving subject may already be slightly out of focus by the time the shutter clicks.
When you use one button to focus track and another button to release the shutter, you are achieving focus at the same exact moment that the shutter is released, therefore increasing your chances of achieving perfect focus.
In order to use this technique effectively on moving subjects, you have to go into the AF-menu and make sure that you have selected "release priority". This will allow you to release the shutter even if the camera doesn't recognize perfect focus. The last thing you want when shooting action is for the AF to hesitate, because it hasn't recognized perfect focus, or because the moment of focus has passed with the movement of the subject. If you are in AF-C mode and you keep the "AF-On" button depressed, it will continuously track your subject and keep it in focus. All you have to do is press the shutter button at the same time, and the camera will fire off a few shots while simultaneously focusing on your subject. Chances are very good that you will get that subject in focus, even if it is moving very quickly."
Het belangrijkste voordeel lijkt mij dat je zowel AF-S als AF-C tegelijkertijd ter beschikking hebt !
Ik heb geen idee of het de AF-prestaties van de Pentax camera"s 'verbetert' , misschien kan Thoran als adept van deze techniek hierover meer kwijt.
Topic: Back Button Focusing (gelezen 8566 keer)