What is ppi pixels per inch

The term PPI is not used much. Many people confuse PPI with DPI or have never heard the term PPI. PPI is a measurement of the quality of a print and understanding this term and what the number means can help you determine the right sizes and resolutions for your next digital photo print. PPI: stands for Pixels per Inch. PPI describes the number of pixels per inch in a photo. PPI is a function of the number of pixels the camera’s sensor supports (also known as megapixels) and the size of the photo. To calculate a photo’s PPI simply multiply the page length by its width in inches. The result is the number of square inches on the page. Now divide the number of pixels the sensor supports by the number of square inches. The result is the number of pixels per square inch. All that is left to do is to find the square root of this number. Following is a table that shows the PPI for various page sizes for a 5 megapixel camera. page size 4X6 - 456 PPI page size 5X7 - 377 PPI page size 8X10 - 250 PPI page size 11X14 - 180 PPI page size 16X20 - 125 PPI page size 20X30 - 91 PPI

Get the most out of your camera. part 2

In part 1 of: Get the most out of your camera, we looked at how to use the aperture and the creative uses of depth-of-field. In this part we’ll look at how to use the shutter button on your camera and how both the shutter and the aperture control exposure. The shutter is a mechanical device that controls the length of time that light is allowed to act on the film. Most standard cameras allow us to use a range between 16 second and 1/1000 second. You might be wondering, why anyone would use a long shutter time of 16 seconds: I’ve used this and even longer shutter times when taken lowlight landscape images. I would always advise the use of a tripod with these long exposures time to avoid blur images. Using a shutter speed of 1/125 second should safely avoid overall blur due to camera movement if you hold the camera by hand. Any longer shutter time should require a tripod. Each time you open the shutter by one, we double the light, when we close down the light by one we half the light. Open the shutter at 1 second allows twice the light as that of a Ѕ second. The shutter can also be used creatively when taking landscape images or sport images. If you want to add motion to your image a slow shutter speed can give an image an extra bit of sway. No more so than taking images of streams. Using a slow shutter speed when photographing water will cause the water to blur, resulting with the image expressing motion. By contrast, a fast shutter speed of 1/250 would be used in shooting wildlife or where the subject that you’re shooting needs to be still and sharp. Most wildlife photographers would use a fast shutter speed. By using the shutter and aperture together we control exposure. Both allow light to enter the camera: the shutter by time and the aperture by the size of the hole in the lens. For example: you’re shooting a landscape scene; you get an exposure reading at f/11 at ј second. You know that by using f/11 that the entire image wont be sharp. You want to shoot at f/22, which is four times less light than f/11. You need to quadruple the light through time; each time you open the shutter by one you double the light, so open it by two stops and your exposure time will be 1 second. Your final exposure should read f/22 at 1 second. At the best of times, calculating the correct exposure can be a difficult task, but with a few simple tips our images can produce eye-catching colours that we see all around us every day.