Location
Upper East Side
Rating - 100%
21   0   0
Something new that we're going to try here every two weeks is to have a "photo focus", where we look at one aspect of photography and sort of play around with it. No matter what your level of photography skill, you can always get better, you can always practice and you can always challenge yourself. I thought I'd start with a technical fundamental of photography - the aperture.

In photography, the word "aperture" refers to the size of the opening of the diaphragm inside of the camera lens that regulates how much light your film is exposed to. In other words, its a resizeable hole on the inside of the lens. When the hole is small, only a little light gets through and when the hole is large, a lot of light gets through. The "f-stop" refers to the aperture and the larger the f stop, the smaller the aperture - i.e. f/2.8 is a very large aperture whereas f/32 is a small aperture. If you are using an SLR, you can see the fstops listed around a black ring on the part of your lens closest to the camera body. If you are using a point and shoot, there should be a manual setting in one of your menus where it will give you an option of how to change the fstop - refer to your user manual.

Why do we care? Aside from getting a proper exposure on your photos, the size of the aperture will affect your depth of field. Depth of field refers to how much of the picture is sharp and in focus. A shallow DOF means that only items in the foreground will be in focus. A deep DOF means that the entire frame with be in focus.

Yesterday I took two photos of my tank from exactly the same place, one with the largest aperture possible (f2.8) and one with the smallest aperture possible (f32) to illustrate how aperture affects DOF. If I had moved the camera closer to my subject, the difference in DOF would have been even more dramatic - however, I was limited by the legs on my tripod.

3275650068_c401d69eee_o.jpg

left: f/32 - right: f/2.8 w/ 100mm macro lens.

So here is my challenge to you - take the best photo you can using either a very large aperture or a very small aperture. If you have a digital SLR, you should be able to spin a wheel at the top of the camera to put your camera in Av mode. Av mode allows you to select an aperture size and have the camera automatically choose the right shutter speed for the right exposure. Or you can use your camera in M mode and select both the aperture and the shutter speed. If you are using a point and shoot, there is probably a menu that allows you to change the shooting mode - you should also choose either M or Av and indicate the aperture you want. If you have a Canon, it can probably be done by changing the mode on the top of the camera.

Post your pictures here! Tell us what your aperture was and what kind of camera you were using. All photos will be considered for POTW. :)

Here is my best shot from yesterday:

3274828315_260529f126.jpg

f2.8, Pentax K20D, 100mm macro lens.
 
Location
Upper East Side
Rating - 100%
21   0   0
It depends on what you mean by "noise". The smaller the aperture > the larger the fstop > the deeper the DOF. So when I take full tank shots, I usually shoot on an f/8 or an f/11 so everything is crisp to the back of the tank. If I am shooting macro stuff, I'll shoot at an f/2.8 or lower, then the background is all fuzzy.
 

LeslieS

Advanced Reefer
Location
Manhattan
Rating - 100%
9   0   0
Great idea. I am finally going to learn how to use my camera :)

I practiced this for a while. My pictures still awful, but they consistently look better when I use a smaller aperture. I guess that my pictures are always so blurry that the extra blurriness in the background makes them look even worse.

The first one is f-stop 22, the second f-stop 3.5
 

Attachments

  • f stop practice 003small.jpg
    f stop practice 003small.jpg
    52.8 KB · Views: 651
  • f stop practice 004small.jpg
    f stop practice 004small.jpg
    46.3 KB · Views: 650
Last edited:

LeslieS

Advanced Reefer
Location
Manhattan
Rating - 100%
9   0   0
I actually took better pics with my old SLR - crazy right?

Anyway, how about some more people posting a few shots of the same thing at different F-stops? I thought posting my ugly pics would give all my fellow bad picture takers some courage. :smile:
 

gholtmeyer

Experienced Reefer
Rating - 0%
0   0   0
I am very thankful for this thread! I have a Canon Rebel XT EOS. I have two lenses for it. One is the Canon EFS 18-55mm that cam with it. The second is a Vivitar 100/3.5 macro lens. I can not find the manual that came with the camera. So, does anyone know how to change the aperture? I really want to improve my photog skills. I have attached one pic that I took just now with the macro lens. I have no idea of the f stop, aperture, sorry.
 

Attachments

  • IMG_3219.JPG
    IMG_3219.JPG
    933 bytes · Views: 105
Last edited:

SaltyFlip

Percula Agent
Location
Elmhurst
Rating - 100%
13   0   0
Here are more examples:

A.) f/22 iso-200 shutter: 3"
S1pbn.jpg

notice the detail, the distinct outlines, and how the DoF (Depth of Field) is deeper. The background tends to compete for the viewer's attention.

B.) f/1.8 iso-200 shutter: 1/50
kDnUy.jpg

notice the smoothness of the edges and how the DoF is shallow. The number is isolated from the background, drawing the viewer's eyes directly on the intended subject.

Since I most often take my pictures on the Manual setting, I need to adjust the f-stop along with the shutter speed; the smaller the aperture the longer the shutter window/exposure time must be for there must be enough light to illuminate your image; or else you'll end up with shadows. Also, for a small aperture, a tripod or stable surface is necessary; otherwise the image will have movement blur.

Try tinkering with your cameras and take pictures of anything; from your fish tank to leaves from the park, and post it up for us to see.

Here's mine but my white balance isn't calibrated
gUlGI.jpg


edited to sync terms with OP.
 
Last edited:

Sponsor Reefs

We're a FREE website, and we exist because of hobbyists like YOU who help us run this community.

Click here to sponsor $10:


Top