Last modified on 15 December 2008, at 01:54

OC Photography Program/Digital Photography

Camera TypeEdit

Camera type if important depending on what you are looking to get out of your camera. Before buying a camera really think about what you want to accomplish with your camera as well as where you think you want to take your photography interest in the months to come.

MegaPixelEdit

How do the megapixels affect your image?

A megapixel represents one million independent points of color/brightness/hue/luminosity ect. The more pixels that are used to represent an image, the sharper and more distinct that image will become when printed. A digital camera usually captures 72 pixels per inch (which can be altered later to suit the requirements of the print) and in turn, its 'image size' is a factor of the 'megapixels' that camera is capable of recording.

What size prints can I get from the many different range in megapixels?

Term:ppi=points/pixels per inch

My camera just made me an image whose dimensions are 3488x2616 or 9 124 608 pixels. Its a 9.1 megapixel camera, and 48.444 inches by 36.333 inches are the dimensions of the 72 ppi capture. What a photographer needs to know about digital images, is that while 72 ppi are fine for display on the computer screen, its absolute garbage for a print. A minimum of 200 ppi are required for any acceptability of quality, and 300 ppi the minimum required for photographic quality.

You could print any image up to six feet across... but it wont be pretty. One must always consider how close the viewer will be to the final print when its on display... The farther the image, the less aparent points/pixels will become.

To figure out how big a quality print your camera can make, you need only convert the PPI to at least above 200, and higher if possible.

Image FormatsEdit

  • Jpeg (Joint Picture Experts Group) Format is the major format that is used buy Point & Shoot(or Compact Digital) cameras and is an option on most [Digital SLR] Cameras. It is a compressed form of bitmap image.
  • Tiff (Tagged Image File Format) is available on some high end Point & Shoot cameras as a replacement for Raw format.
  • Raw (.RAW, .CRW(Canon), .CR2(Canon), .NEF(Nikon), .PEF(Pentax) .DNG(Adobe)) This format is the digital equivalent of a film negative, and is designed for high end cameras like Prosumer Point & Shoot and Digital SLR Cameras, Raw format enables adjusts in more ways than conventional Tiff or Jpeg images and consists of data direct from the cameras sensor with little to no in-camera processing applied, available adjustments include Exposure, Color Temperature, Sharpness, Brightness, Contrast, Gamma and others.

Digital NoiseEdit

Image on the left has exposure time of >10 seconds in low light. The image on the right has adequate lighting and 0.1 second exposure.

What is digital noise?

Digital noise is created from heat generated by the cameras CCD(sensor). Digital noise or Image Noise (often shortened to just 'noise') can also be caused by a buildup of charge on the CCD. It usually occurs when using long exposure times or high ISO settings. The amount of noise varies greatly with different models of camera but is not usually a problem at ISO 400 or lower, or when using shutter speeds of under 2.5 seconds.

How to avoid it?

There are a few ways to avoid buildup of noise:

  • Use as low an ISO setting as practical
  • Use as short an exposure time (shutter speed) as conditions permit
  • Try not to underexpose dark areas of the image

How to fix it

The simplest way to fix noise is by avoiding it all together. If your camera has a 'noise reduction' option in the menu, turn it on for long exposures. Image manipulation software such as Adobe Photoshop and Jasc Paintshop Pro have noise reduction filters available, but these tend to introduce a degree of blurriness into the image.

Digital Darkroom ApplicationsEdit

Photoshop

PaintShop Pro

ULead PhotoImpact (low cost, intuitive)

The Gimp (absolutly free, highly recommended)

Photoshop Elements (cheaper version of photoshop)