V1.02
Thom Hogan’s Complete Guide to the Nikon D300
Page 382
the horizontal and vertical axis, while the remaining 36
sensors are lines that only detect contrast in the horizontal
axis (when holding the camera normally). Here’s what the
viewfinder shows for the shape and locations of the sensors:
And here’s what the actual size and shape is more like:
Notice that the outer sensors are lines, while the inner group
are crosses.
One thing that intersects with sensor shape and size is subject
size. One of the classic issues with wide angle lenses and
autofocus systems is that very small objects you’re trying to
focus on—they’re small because the wide angle lens has such
a wide area of view—sometimes don’t occupy enough of an
individual autofocus sensor for the camera to make a
determination of where focus should be.
Indeed, this is something you need to watch for in general: if
what you’re focusing on is visually smaller than the autofocus
