Focus
Priority simply means that your camera will refuse
to take a picture until it can reasonably focus on something.
Release Priority means that the camera will
take a picture when you decide to take it, regardless if anything
is "in focus" or not. (Read the last paragraph a
few times for clarity until it sinks in.)
Now, you might ask yourself “why is
there such a setting as Release Priority?” Well, many
professional photographers are shooting high-speed events
at high-frame rates, taking hundreds of images, using depth-of-field
(or experience and luck) to compensate for less than accurate
focus. They are in complete control of their camera’s
systems relying on a huge amount of practice in getting the
focus right where they want it to be.
So, clearly, there are valid reasons for certain
photographers not to use Focus Priority. But, most of those
same photographers do not let the shutter release button start
the autofocus either, since the focus would change every time
the shutter button is pressed. They set Custom Setting a6
so the autofocus does not even activate until the AF-ON button
is pressed. (see manual page 151) They then use the AF-ON
button for their autofocus, and the shutter button to take
the picture. They separate the two functions instead of using
the shutter button for both.
You need to ask yourself, “What type
of a photographer am I?”
If you are a pro, shooting hundreds of pictures
of fast race cars, focus priority may not be for you. But,
for the average photographer taking photos of his kids running
around the yard, a beautiful landscape, flying birds, or a
bride tossing a bouquet, Focus Priority is the best choice.
For most of us, it’s better to have the camera refuse
to take the picture unless it is able to focus on your subject.
When shooting quickly, focus priority may
cause your camera to skip a series of out-of-focus images.
Focus Priority will slow down your camera’s frame rate
so that it will not reach the maximum 5 frames per second.
But, I have to ask, what is the point of 10 out-of-focus images
and 5 in-focus images? Why waste the card space, and then
have to weed through the slightly out-of-focus images?
In
Figure 1 below are pictures of the series of menu screens
used to set Release vs. Focus Priority.
For
AF-C Mode using Custom Setting a1:
|
Figure
1– Custom Setting Menu screens for a1 |
The factory default is for “FPS Rate”
priority. Most of us will want to change that to “Focus”
priority. (FPS = Frames Per Second)
“FPS rate” and “FPS rate
+ AF” are both forms of Release Priority, with “FPS
rate + AF” giving “improved” autofocus while
still allowing the image to be taken no matter what. For reliably
sharp focus in AF-C mode, use Focus Priority. On this menu,
it’s the bottom “Focus” selection.
Now, let’s turn our attention to AF-S
mode and Custom Setting a2. We need to verify whether Focus
or Release Priority is set. Examine Figure 2 for the correct
sequence of menu items.
For
AF-S Mode using Custom Setting a2:
|
Figure
2 – Custom Setting Menu screens for a2 |
In figure 2, your choices are “Focus”
and “Release.” Since the factory default is Focus
Priority, it may already be set to “Focus.” If
not, then select Focus. Now, your D200 is set up to take an
image ONLY if it can focus on your subject, no matter what
AF mode you choose.
