Digital Camera Resolution – Digital Photography Tip of the Week

I have been asked several times what equipment I use, and what to look for in a digital camera. We’ll start with the easy one, my equipment.

My digital equipment consists of a Canon EOS 10D which is a 6.3 MP digital SLR with a APS-C sized sensor. My lenses are a Canon 28-80 EF III USM, Canon 75-300 EF III USM, and a Sigma 180mm macro lens. I also have other various equipment that I use with the camera. The two Canon lenses are from my previous film camera, though they work fine with the digital. The Sigma lens is primarily used for close up work. I also have a 2.1 MP Fuji point and shoot digital camera that I use occasionally when I don’t want to carry around my larger camera and know I won’t be printing larger than 4″ x 6″.

Now the harder part of today’s tip, what to look for in a camera. There are several factors involved in buying a camera, features, prices, resolution. Today I will discuss resolution.

There is a very big push these days for cameras with higher resolution (more megapixels). This alone should not be a deciding factor in your purchase of a camera. For most people, camera resolution should not make much difference. I’ll explain why.

Your image is made of pixels, or dots. The number of pixels in an image determine how fine detail can be in the printed photo. The more the better, up to a point. A 4″ x 6″ print when printed at 300 DPI (dots per inch) needs a total of 1200 pixels x 1800 pixels to print, which work out to be just over 2.1 million pixels (2.1 megapixels). At that printed resolution (300 DPI) you can easily print up to a 6″ x 8″ print with a 5 MP camera. However, photos printed at a commercial lab (or even a big box or drug store lab) will look just fine printed at resolutions as low as 180 or even 150 DPI. At 180 DPI, a 5 MP camera will allow you to print an 11″ x 14″ print, and at 150 dpi, a 12″ x 18 ” print. So, how large do you really need to print? Most people I talk to rarely print larger than an 8″ x 10″ print, and even then that is only occasionally. The table below summarizes the various print size and the MP needed to print at that resolution. My recommendation is to use 180 DPI as your guide to ensure better photos.

Camera Megapixels Needed

Print Size
180 DPI
150 DPI
4 x 6
.78
.54
5 x 7
1.1
.79
6 x 8
1.6
1.08
8 x 10
2.6
1.8
11 x 14
5.0
3.5
12 x 18
7.0
4.8
16 x 20
10.4
7.2

I have checked a few of the large online photo printers, KodakGallery.com, Snapfish.com, iprintfromhome.com, walmartphotocenter.ca, and photolab.ca, and even the resolutions stated above are more than what they are recommending. For the average user, a 5 megapixel camera should supply enough resolution to meet their printing needs, and even cameras as low as 3.5 MP should be just
fine.

One drawback of larger megapixel cameras is the file size. As the sensor size grows, so does the files size. You will be able to store less images on a given size memory card of a higher megapixel camera than that of a lower one. This also means that you will fill your hard disk on your computer faster and will require more CD’s or DVD’s to back up the same number of images.

Next week, I will discuss the other features to look for when purchasing a digital camera.

 

The digital photography tip of the week is written by the PCIN Assistant Editor, Chris Empey. Chris is a long time photographer and is currently the vice-president of the Niagara Falls Camera Club. You can see more of his photography at his Photo of the Day website.
If you have a tip to send Chris, or a question about digital photography he can address in the newsletter, send it to chris@pcin.net.

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