Photography Information

Why 1.5 Megapixels is Enough


Dots Per Inch is a useful measure of relative resolution. But if you don't know the image size in inches or some other measure of size, then the amount of dots per inch doesn't mean much. That's why DPI is used in conjunction with scanner Specifications, because you know that the size is going to be 3.8 by 1.7 inches!

Different resolutions are used for different purposes. 72 or 75 DPI for screen viewing; 250 for digital photography and 300 dpi for printing. See how this is a nice comparison, yes, you can get away with 50 less pixels per inch in your photographs than would be required for A4 printing, this is because of the physical size of the photo!

Dots Per Inch specifies how much information is resolved in a picture, whereas the number of megapixels is usually used to describe the total output size (in pixels) of an image.

Example: I want to reproduce the standard photograph size. This would be 6 by 4 inches. Digital photography requires a minimum of only about 250dpi, So: 6 * 250 = 1500 and 4 * 250 = 1000, so you need an image sized about 1500 * 1000 pixels (about 1.5 megapixels). Thus you can get a perfectly good standard print from a 1.5 megapixel camera!

If you take a photo twice, one at 5 and the other at 1.5 megapixels, than ask your self which one looks "better"? They will both look reasonable because your computer generates colours such that the image looks better than it really is; if you were to print both as a 6 by 4 image, they will look identical, because your printer can't generate more than 300 dpi so the "better" image is effectively reduced in quality anyway. This example demonstrates how it is possible to literally waste memory, ie for everyday use the additional memory required for the other 4 megapixcels gives you no real benefit!

This is quite good because a 36 Megabyte media card can store 50 to 65 images at 1.3 megapixcels but only 8 to 10 at 5 megapixcels, so unless you are planning on getting your images printed larger than 6 by 4 there's no real advantage to the full 5 megapixcels.

Now we have established that a 1.5 megapixel camera will produce a 6 by 4 inch standard photograph, that is, it will generate a resolution such that each pixel is simply reproduced "as is", we come to the more interesting issue of enlargement.

If you wanted to print your 6 by 4 inch image as a 10 by 8 photo (which would normally need the full 5 megapixels), there would not be a sufficient number of pixels for the additional surface area, so we now need to scale up the existing pixels by "resampling" the existing pixels, a process which estimates how the "missing" pixels should appear, and fills them with the appropriate "colour". A 25% resample

I am the website administrator of the Wandle industrial museum (http://www.wandle.org). Established in 1983 by local people to ensure that the history of the valley was no longer neglected but enhanced awareness its heritage for the use and benefits of the community.


MORE RESOURCES:

News, analysis, color and photography from Cox Newspapers ...
Atlanta Journal Constitution,  USA - 19 hours ago
The entry titled "Invesco Field: Too big for Barack?," and any of the comments about it. DEMOCRATIC CONVENTION COVERAGE: Watch this space for frequent ...


Queen Anne peeper charged for upskirt photography
Seattle Post Intelligencer - 37 minutes ago
By LEVI PULKKINEN A 44-year-old Seattle man has been charged with using a hidden camera to peep up women's skirts at a Queen Anne neighborhood supermarket. ...


Microsoft's Photosynth Deepens Digital Photography
Washington Post, United States - 3 hours ago
Three times yesterday, I had co-workers ask me to show them one of the "synths" I'd created at Microsoft's Photosynth site, the subject of today's column. ...


Malaysia Star

Photography exhibition an eye-opening experience for many
Malaysia Star, Malaysia - 19 hours ago
“I also like the fact that these photos are natural and not posed like in magazines,” added Sharifah who is quite keen on photography. ...


Photography win no set-up
Taranaki Daily News, New Zealand - 2 hours ago
... has won a New Plymouth photographer a rare gold at the New Zealand Institute of Professional Photography awards in Tauranga earlier this week. ...


Photographer opens gallery in Middletown
WTOP, DC - 6 hours ago
Hough, 27, took courses through high school and went on to major in studio arts with a focus in photography at Mary Washington College in Fredericksburg, ...


Amateur Photographer

» Photography history prized open on Flickr
Amateur Photographer, UK - 5 hours ago
Initially, three collections from the National Photography Collection will be available online. 'The site allows the public to contribute information and ...


Digital Photography News
Shuttertalk, Australia - 4 hours ago
I'm about to start a project to create a photo book, and have almost decided to use Blurb to handle the publishing. I know a couple of people (not to name ...


Telegraph.co.uk

Dazzling smile helps win environment photography competition
Telegraph.co.uk, United Kingdom - Aug 27, 2008
By Paul Eccleston An uplifting picture of a poor farmer's wife in India carrying an infant on her back after a hard day's work in the fields has scooped top ...


"Exhibitions Connect Photography, Collage, Textiles to Explore ...
Absolutearts.com - 15 hours ago
Three concurrent exhibitions at the Southwest School of Art and Craft embed photography in other media to ask viewers to consider – what is the truth? ...

Photography - Google News

home | site map
© 2006