Image Sensors and Megapixels
When it comes to choosing the right equipment for the job, ensuring you can take the right image quality of image is important. An area where some have a basic understanding, but never take it further, is with a camera’s image sensor.
Many photographers understand that a higher megapixel rating will result in a better quality image when making large prints, but what does that sensor’s rating really mean?
Having a clear understanding of image sensors and megapixels is important to choose the right photography equipment for any given job.
Image Sensors and Megapixels
As you likely already know, the image sensor is the part of your camera that actually captures the digital image. The sensor is capable of taking light and converting it to an electric signal. Using these signals your camera converts the information into a digital image.
Each sensor is capable of converting only so many pixels with one shot. With that, image sensors are rated in megapixels (1,000,000 pixels).
A camera that uses a 6 megapixel sensor is capable of producing images that are 6,000,000 pixels in size. When set for a normal shot a 6MP camera would capture an image that was 3000pixels x 2000 pixels.
So what does that mean to your printed work? Let’s take a look.
When you print a picture, it is the number of pixels per inch (ppi) that determine the quality of the print. An excellent photograph can be had with a 300ppi print (or close to it).
150 ppi = Fair Printed Quality
200 ppi = Good to Very Good Prints
300 ppi = Excellent Printed Quality
Given that, with our 6MP image, we could print an excellent quality image of (3000/300 x 2000/300) approximately 10 x 7. In other words it would make a decent quality 8 x 10 print. If you wanted a larger than 8×10 print you could expect a drop in quality, or you would need a better image sensor.
Choosing Your Photography Equipment based on Imaging Needs
With an understanding of how your image sensor affects the quality of your prints let’s talk about cameras.
When you’re choosing the right camera for any given job you now have a basic guideline for which camera to use. For portrait work your 6MP camera is likely enough. You will be able to print excellent quality 8 x 10s and even good quality 10 x 13s (with a resolution of about 230ppi).
If you required larger prints, or more detail in your images, you will need a bigger sensor.
As an example Kodak’s new 50MP sensor could take an aerial photo of 1 ½ miles in width. With the 50MP quality you could clearly see something as small as a notebook computer (about 1 foot square). You could also maintain excellent quality with your prints up to about 27” x 20” prints.
With a better understanding of how megapixels translate into printed work, you should now be able to choose the right camera for the job, everytime!
