Terry Lang Photography

BASIC Photography

BUYING A DIGITAL CAMERA
 
  To give the student valuable and viable up-to-date information to be able to make a knowledgeable decision in purchasing, and using, a digital camera.
 
What is a digital camera?
 What is a megapixel?
 What are storage devices?
 What are the different controls on a camera?
 Why do I need a digital camera?
 What resolution should I shoot at?
 
 
1. What is a digital camera?  To simplify terms, a digital camera is a recording device.  It is nothing more than a camera that uses electronics to record an image instead of silver halide film.  A camera is a light tight box with a lens to focus the light and a recording medium to save the image.  
 
   Before we get into the real specifics of a digital camera, there are some terms and definitions that we need to get out of the way.  Photography is an application of scientific principles to achieve artistic results.  The fun part is that no matter what you want your final image to be, getting there is always the same.  We need light, we need a method to control the amount of light and we need something to record the light on.
   All photographic images are reflections of light from objects.  The lens of the camera passes the reflected light from the object and it is here where we need to control the intensity of the light.  This is done by the aperture and the shutter.
   The aperture is the physical opening of the lens and is measured as a term called the f/stop.  Because the f/stop is the result of a mathematical formula, we need to remember that the smaller the number, the larger the opening.  
   In reality, the f/stops of lenses are listed as:
1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22…
   These are called the whole f/stops and as we move to the right on the scale, each number allows in exactly ? the amount of light of the number on the left.  This will become important later when we discuss depth of field.
   Right now, the important thing to remember is that amount of light becomes less as we go to higher numbers and that each step to the right is ? the light of the previous step.
   The shutter of a camera is a physical device that allows amounts of light to pass through the lens in a certain time.  The scale for shutter speeds is:
2, 1, 1/2, 1/4, 1/8, 1/15, 1/25, 1/50, 1/100, 1/250, 1/500, 1/1000
Although the numbers aren’t exact, each step to the right allows 1/2 the light of the previous step.
    How do we measure the amount of light coming from an object and better yet, how do we control it?  Well, camera manufacturers now build light exposure meters into virtually every camera made today.  And, these meters measure, at the least, the amount of light that falls on the lens.  Built in light meters measure the intensity of the light as an electronic signal and then set the camera controls to what the meter believes is an average exposure for that intensity.
   Digital cameras are exactly the same as film cameras with the substitution of an electronic recording device, called a “chip” for the film.  This recording medium is made up of a number of picture elements, called pixels.  Pixels are not sensitive to a certain light frequency; in other words, pixels are color-blind.  All cameras have something in front of the chip to ensure that certain pixels receive certain frequencies of light.  This is commonly called the Bayer Pattern and for each 4 pixels, there is a filter for red, blue and two green.
Laurel and Hardy photo courtesy of the Herman Goelitz Candy Company, Inc.
   
   Now, can we see that if we only had 3 pixels, 1 for red, 1 for blue, and 1 for green, that our final image might look pretty spotty? This is “pixilation”.  If we can make the pixels as tiny as possible and put as many as we can into a certain physical space, our photos become better and clearer and less pixilated.  The important thing to remember is that there is a point of diminishing return with the amount of pixels that we can force into a space.
   To add more pixels and get better resolution, we must crowd them together or make them smaller.  If we crowd them together, they start to interfere with each other, cause heat, and this causes “noise”.  And, the smaller the pixel size, the less information that is recorded and the harder the image processor has to work, causing more heat, causing more “noise”.  
  The number of pixels is called resolution and the more pixels, the higher the resolution.  People get confused by the terminology because most salesmen don’t know what they are talking about.  We hear, 3 megs, 4 megs, 5 megs or 3 megapixels, 4 megapixels, 5 megapixels.  Or, we see 2034x1028, 640x480.  We count the number of pixels across and multiply by the number of pixels down on the chip and that gives us the megapixel count.  For example, 2048 across, 1028 down gives us 2 megapixels or 2 megs.  The highest resolution of the camera is always the one that is listed or talked about.  Most every camera allows you to lower the resolution or increase to the max for each separate shot that you shoot.  
  If a camera in the store has a rating of 6mp, you can bet that it has approximately 3000 pixels across, and 2000 pixels down.
   There are two reasons for a person to consider buying a camera with a higher resolution: they want to make very large prints of 13”x 19”, or bigger; or, they believe what salesmen say about bigger is better.  This is the bunk that the computer industry has been telling us for years!  YOU must determine what you want for the final product and that will determine what resolution you need.  
 
LET’S TALK ABOUT THAT FOR A MINUTE BECAUSE IT’ VERY IMPORTANT.
RESOLUTION DETERMINES FINAL OUTPUT.
 
   If all you needed your camera for was to sell things on ebay and you would never, ever, make prints, then a very low resolution camera of less than 1 megapixel would be adequate.  Why?  Each image that you record becomes a file on your computer and low resolution images are small files.  People who surf ebay to buy things, want to look at photos but they don’t want to wait for the photo to load.  A large file, that is a high resolution photo, takes too long to load.  By the time it loads, the potential buyer has gone on to the next seller.
   If you plan on making 4x6 inch prints and nothing bigger, than a 1 or 2 megapixel cameras will suffice.  For 5x7 and 8x10 size prints, a 3 meg camera is okay.  A 4meg camera is good for 11x14s and larger prints require higher resolution.  As you increase resolution in a camera line, you naturally increase cost.
   What is the actual resolution difference between the various megapixel sizes?  
 
More to come... 
 
 
 
 
 

Terry Lang Photography

Retired Navy Photographer...specialize in scenery and flowers...well-versed in digital...vast experience in teaching...travel throughout the Pacific Northwest looking for scenery, flowers, and wild life...DO NOT DO weddings nor graduations...avid golfer and grandfather. Please drop me a line with questions or concerns.

Latest Blog Articles

Administrator Menu

User Login