Assignment #4

For this weeks assignment we experimented with our f-stop and ISO of our cameras.  This required taking a series of pictures, holding the same frame, and adjusting our f-stop or ISO with each picture.  For the f-stop test, we were trying to determine when our camera put everything into focus.  For ISO, we needed to find at what number the "noise" was too loud.  I'll only post a few of my pictures.....since they are all pretty much the same scene.

1. Series of pictures with a variety of apertures - with Camera mode set to Aperture-Priority and lens at 35mm.
     a. At 3' from camera
Here my f-stop is set at 5.6.  I went all the way up to 32.  I found that at f-stop 11, everything was pretty much in focus and I probably don't need to go all the way to 32 to have complete focus.

     b. At 15' from camera
Again - I'm at f-stop 5.6.  You'll notice that since I stepped away from my main object in the picture, everything is pretty much in focus.

     c. Picture w/ Min Depth of Field

     d. Picture with Max Depth of field

2.  Series of pictures with a variety of ISO settings - with Camera mode set to Programmed Auto.
- Its hard to see in these pictures, but in class the pictures were blown up.  As my ISO increased - you could see "noise" in my pictures.  They were more grainy and edges lost their sharpness.  When we zoomed in, I started to experience a lot of "noise" around ISO 800.  He suggested we make a few prints and see how the pictures develop to determine when the "noise" causes issues with the picture.  Apparently the application Light Room is able to eliminate a lot of the "noise".  Still not sure if I want to buy the application.....we'll see.

     a. First we took pictures outside.....

     b. Then we took pictures inside.....

Class #4

Lenses.....Part Two!- For this class we covered Depth of Field with the lens.  Depth of Field is the amount of an image that is in focus in front of and behind the main subject.  This is important in creating image composition.....the viewer's eyes will only want to stay in areas that are sharply focused.  We can alter depth of field three ways.....

1. F-stop - The larger the f-stop (smaller the number) the shallower the depth of field, while the smaller f-stop (bigger the number) creates a greater depth of field.  So with a smaller f-stop, objects behind the main subject will appear more out of focus.

2. Lens Focal Length - The longer the lens the shallower the depth of field, the wider the lens the greater the depth of field. 

3. Camera to Subject Distance - The closer you are to the subject the shallower the depth of field, the further away you are the greater the depth of field. 

ISO
We covered ISO briefly in our last class.  The ISO is a measure of light sensitivity to your chip.  One down fall of adjusting your ISO is noise.  The higher the ISO, or increase in electricity running through your chip, the increase in noise.  Noise is the chip adding randomly colored pixels in areas that should be black or very dark.  Noise is caused by the low level electrical charge of the chip actually creating ghost information.  Better cameras have less noise, but all cameras will show some noise at certain setting.  Part of this weeks assignment is to determine at what ISO setting we start to experience too much noise with our camera.

Class #3

Today we learned about lenses and how to operate our camera in Manual mode (adjusting f-stop, ISO and shutter speed).  We scratched the surface with both.....so more to come.

Focal Length and Angle of View
- Your lens is the single most important tool of as photographer.  The camera is just a dark box, while the lens manipulates the light and projects the image to the chip.
- When adjusting your focal length - you are expanding and contrasting the field of view and manipulating the spacial relationship.
- Lenses are measured by their focal length.  This is the theoretical measurement from the center of the lens (nodal Point) to chip when focused at infinity.  The smaller the focal length,  the wider the angle of view.  Longer lenses have smaller angles of view, resulting in a greater image magnification.
   * 20mm lens is a wide-angle lens with an angle of view about 90 degrees
   * 50mm lens is considered a normal lens because the angle of view is roughly that of our vision - 45 degrees
   * 300mm lens has an 8 degree angle of view

- Wide Angle - Show more of a scene than a normal lens.  They exaggerate and expand perspective by making foreground objects large and distant objects small.  Wide lenses can distort lines close to the edges further adding to the illusion of perspective.

- Normal Lens - You are pretty much showing the viewer what they would see through their eyes.  A Normal focal length is around 35mm.

- Long lenses (telephoto) - Pull subjects closer to the camera.  Long lenses tend to compress the scene making objects appear closer to one another than they are.  They have have less ability to maintain focus in front of and behind the main subject.  This sharpness fall-off can help to restore the illusion of depth.

Manual Exposure Fundamentals
To find the correct exposure for your picture, you need to find a balance in the amount of light in your scene to the amount of light your chips needs to capture the tones and colors accurately.

- f-Stop or Aperture - This is the diaphragm of your lens just before you release the shutter button.  The "f" in f-stop stands for factor, as the number is the result of dividing the focal length of the lens by the actual size of the opening.  All you really need to know is - the bigger the number, the smaller the hole.

- Shutter Speed - This is the amount of time the shutter stays open.  It is expressed as fractions of a second.  So 125 is 1/125th of a second.  The important thing is - a slower shutter speed can cause blur.

 - ISO - This is the numerical expression of your chip's light requirement....or adjusts the sensitivity of your chip.  This is the amount of light that the chip needs to accurately represent tones and colors.  The higher the ISO - the more electricity and more robust charge.  This can also create noise in your picture (more next week).  For low light scenes you'll want a higher ISO, starting around 1600.  For sunny days, start with an ISO around 200.

- Meter - To make sure you're reaching the correct balance of light - you need to read your light meter.  The light meter reads the amount of light in your scene and guides your selection of the shutter speed and f-stop selection - after you've set your ISO.