As was mentioned in the previous post, the two of these are very strong tools in effecting the appearance of a photo by dictating how much of the photo is in focus, and what elements are frozen in place or left to blur due to movement.
We'll start with aperture as it has a bit more that comes into play in the learning curve.
Everything starts with your focus point (are that you are focused on).
Quick note, the numbers below are made up for this example, but their relationships/how they work remain true
We'll used a fixed object (a tree in this case). That tree is 100 feet away from you, and you are focusing the lens on it.
At any given F-stop 1/3rd of the area in focus is on the near side of your focal point, and 2/3rd's on the other side. So 10 feet on the near side of the tree remain in focus and 20 feet on the far side. As the F-stop number increases (from say 5.6 to 18) the aperture opening is getting smaller, and more of the area is coming into focus. Now we have 40 feet in front of the tree in focus, and 80 feet on the far side.
If we open up the aperture to a wider setting, say F/2.8, the field of focus narrows, to say 5 and 10 feet respectively.
Now two things to keep in mind here that will also effect the amount that remains in focus
1: Length of the lens you are using. All else remaining the same, the longer the lens in MM, the less depth of field you'll have in your image
2: The distance from camera to subject. All else remaining the same, the further from your camera the subject is, the larger the depth of field will be.
Here are two examples of photos with a large and shallow depth of field.
In the first, we see a fairly shallow depth of field:
Here in the second, almost everything remains in focus:
The second area we are going to use this week is shutter speed.
Shutter speed is a fairly easy one to understand. The faster the shutter speed, the most motion stopping abilities it has, and the slower it is, the less it can freeze. The object being photographed has the amount of time that the shutter is open to move across the frame, and thus what shutter speed you need to freeze it will depend on how fast its moving, its direction relative to the camera, and how far away it is.
An object moving across your field of vision will require a much faster shutter speed than one coming at or away from you, as its position will appear to be changing much faster. The further away from you it is, the slower you can go shutter speed wise as well, as its relative speed to will seem lower.
As a general rule shutter speeds should always be at least as fast as the length of the lens you are using to avoid bluring from camera shake (in other words if shooting a 50mm lens, a shutter speed of at least 1/50th of a second is recommended).
Regardless of lens length, handholding under 1/30th of a second will result in bluring of an image and some form of support from a tripod/monopod/rest is needed. (note this does not account of IS lenses or larger formats).
Here are a few examples of shutter speeds being used for creative effects:
Here an intermediate shutter speed was used, note the slower moving parts of the birds are in focus, while the faster parts have been blured:
Here a fast shutter speed was used to freeze the subject (note the drops of water in the air around matt reed):
Here a very slow speed was used to allow the moving part of the subject to blur:
So for this project, the 4 photos you are looking for are:
Two for shutter speed showing a fast and slow shutter speed, and how they each show movement (you'll need some form of moving subject for this, an athlete, car, water, etc)
Two for aperture, one showing a large depth of field, one showing a shallow depth of field.
Post to the BT forum and we'll talk about your photos as we go along.
Good luck all.
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