Horizon vs No Horizon: Do you ever NOT want to have
a horizon in a landscape?
answer: When you want to have the emphasis on one subject.
Check out the links above and remember 'no horizon' is
not limited to water.
sense in reinventing the triangle when they have a nice diagram
all set up. Besides, I have no idea how to draw one here :) Be
sure to follow all the links on that page.
It uses the Canon EOS as an example but the principles are the
same for all cameras, the symbols might be a bit different.
Here is a quick look at 'DOF'...
Depth of Field
BasicsWhen a lens focuses on a subject at a distance, all subjects at
that distance are sharply focused. Subjects that are not at the
same distance are out of focus and theoretically are not sharp.
However, since human eyes cannot distinguish very small degree
of unsharpness, some subjects that are in front of and behind the
sharply focused subjects can still appear sharp. The zone of
acceptable sharpness is referred to as the depth of field. Thus,
increasing the depth of field increases the sharpness of an image.
We can use smaller apertures for increasing the depth of field.
The following shows an example. The lens focuses at the middle
between the 3 inch and 4 inch marks. Thus, the 3 inch and 4 inch
marks are sharp in all images. The 5 inch mark is not very sharp at
F3.2, and is improved as the lens closes down to F3.6. Then, it
becomes sharp in all subsequent images. The 6 inch and 7 inch
marks are not sharp until F5.0 and F6.4, respectively. The 8 inch
mark becomes reasonably sharp when the lens closes down to F8.0.
The 9 inch and 10 inch marks are not sharp in all images; but, they
become sharper as the lens closes down. For the foreground, the 2
inch mark is acceptable at F3.2 and becomes "focused" at F4.0. The
1 inch mark is not sharp until F5.6, and the lead of the ruler
becomes reasonably sharp at F7.1. As you can see, the range of
sharpness (i.e., depth of field) gets larger as the aperture gets
smaller. Therefore, use a smaller aperture if a greater depth of field
is needed. Please check the Aperture-Priority Mode to know more
about the use of aperture and its impact on depth of field.
Keep snapping. Carry your camera every
where! Oh we love to SNAP.