Written By onci on Friday, September 18, 2009 | 9:18 AM
A Word on Focus – Getting Razor Sharp Images: Part 1 by Matthew Studebaker
While equipment shake may the number one culprit for soft or blurry images, inaccurate focus probably comes in as a close second. I know of no serious bird photographer who, at the time of this writing, still uses manual focus lenses on a consistent basis. Birds rarely stand still, and auto focus greatly increases the number of accurately focused images. Personally, when I manually focus, I only get about 3 in 10 photos with razor sharp focus, while auto focus often nails 9 out of 10. Auto focus technology is simply too advanced and readily available to seriously consider a manual focus lens for everyday use.
Tips for Acquiring Accurate Focus:
First, while most modern auto focus lenses are very fast at locking on to a bird when the bird is almost in focus already, most lenses are not very good at searching great distances to find the subject. If your lens is pre-focused at 4 meters and then a falcon flies by 20 meters away, you’ll never find it in the viewfinder in time unless you manually focus to about 20 meters and then the auto focus lock on and do the fine tuning. The first rule for using auto focus is to make major focus changes by hand, but let autofocus do the micro adjustments and lock on.
There are two types of focus confirmation commonly available in today’s cameras. The first is a small beeping noise which sounds when focus has been acquired. This noise is soft enough that it would only bother the most shy of birds. In fact, many birds, if they hear it, are curious and give the perfect head turn towards the camera just as you acquire focus. Sometimes it’s great. Sometimes it’s annoying. Once in a while it scares the bird. I usually leave my confirmation beep turned off.
The feature I do appreciate in modern cameras is the focus sensor light. In my sensor array, the sensor(s) which has locked focus turn red for about a half of a second. This lets me know more specifically what exactly the camera is locking on to, and is much less annoying that the beep confirmation.
Posted by onci at 9:18 AM