Monday, January 25, 2010

January 21st, DOF, Basic Mode Zones (AV,TV)

Topic #1: Composition

    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.
Marejle Jones and Danielle Morgan, roping teammates, are going after 
their steer in the HS Rodeo.

ISO: measure of the camera sensor's sensitivity to light
shutter speed: The amount of time the shutter is open
aperture: The size of the opening in the lens when a picture 
               is taken

For this topic I am going to refer you to the link. There is no 
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.

Topic #3: Basic Zone Modes this video on zone modes. 
It uses the Canon EOS as an example but the principles are the 
same for all cameras, the symbols might be a bit different.

Portrait- blurs the background (opens the aperture)
Landscape- everything in focus, big 'Depth of Field' (small aperture)

Here is a quick look at 'DOF'...

Depth of Field


When 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.

Click on the image to see a larger one

Macro- close-ups, a simple background make things stand out
Moving Subjects- telephoto lenses and auto focus best
Night- use a tripod and/or a stable surface....   Trick: if you have 
low light conditions and not a tripod, use your arms braced 
against your body, or prop the camera on your knee. Put
it in rapid fire mode. The first shot will take the shake of your 
finger press and will be blurry. The next should be better as 
the initial shake is past. While not perfect it helps.

TV: Shutter-Priority: you set the shutter speed and the camera 
sets the aperture matching the brightness of the subject. A 
fast shutter can freeze water droplets or a slower one can blur 
them giving them the feeling of motion.
In this picture I have a longer shutter allowing a longer time to gather light,
creating the water to have a softer streaky look.

Here there is a fast shutter capturing the individual water droplets.

AV: Aperture Priority: you set the aperture and the camera sets the shutter speed. A large aperture, f2.8= blurred background. Small aperture, f22= focused background (large DOF)

I don't remember my settings for this picture but it does demonstrate DOF. 
My dog, Angie is in focus in the foreground as she watches the construction 
in the river that is also in focus, a large Depth Of Field.

Again, I don't remember my exact settings, except I opened the aperture to 
blur the background (no horizon to focus on the subject) and got the color 
of other flowers to create an abstract feel.

Assignment: use the other 'modes' of your camera. See what they do and what you 
can do with them. Keep in mind compositon, elements of design and using horizon 
and no horizon.

Photo of the Week- submit your photo(s) to me. I will 
post them on the blog Thursday nights in one posting. No names will 
be placed by them, only numbers. It is important that you keep it 
anonymous. People will cast their votes by making comments on the 
blog for the corresponding number of the picture they wish to win. The 
most votes wins for the week and gets their picture printed and hung. 
Get people to become followers and make educated votes. Voting 
takes place between posting Thursday night and Saturday night. The
 picture will be printed Sunday or according to my schedule.... give or
 take for family plans please :)
Oh snap! When submitting use the regular subject line WHS....Class, 
then make a note to me that the pic is Photo of the Week in the 
message box. 

I know you are all wondering what I did this weekend.....

.... an A-Mazing concert!!

Rain, nor sleet or snow could keep us away!

Got a shot of my other daughter when we got home to sunshine.

Keep snapping. Carry your camera every
where! Oh we love to SNAP.

No comments:

Post a Comment