Megapixels and Sensor Size

Trees in fall color reflect in still pool at Upper Whiteoak Falls in Shenandoah National Park, VA. © Jerry Ginsberg

Story & Photography by Jerry Ginsberg

For several years now, the most popular criterion that we use to compare digital cameras has been a simple megapixel count.

Unfortunately, that metric alone can easily be misleading. When comparing cameras solely on the quantity of pixels, we are not paying attention to the actual size of those pixels. Cramming more and more pixels into the same small space means that these pixels themselves will each become smaller and smaller.  Simple, right?

“So what’s the difference?” you might well ask.  An excellent question!  A smaller pixel has less ability to resolve contrast and minimize noise.  Conversely, a larger pixel has the ability to provide an image file with a relatively greater contrast ratio, therefore rendering a higher dynamic range and less noise, given the same circumstances.  Naturally, these improved attributes should result in a better capture file.

A warm summer sun rises slowly on a foggy morning in Jasper National Park, Alberta, Canada. © Jerry Ginsberg

It is for this reason that for the past couple of years we have seen not only a bit of a cooling of the megapixel wars among competitors, but an actual reversal in those counts. Some popular camera brands have cut back on pixel counts as a means of producing better RAW files.

Unique tufa formations (calcium carbonate) silhouetted in pre-dawn light in Mono Lake. Mono Lake, CA. © Jerry Ginsberg

So how can we get the best of both worlds; more, but larger pixels? I thought you’d never ask. The answer is not an overly complicated one. A larger sensor allows for larger pixels. Voila!

Let’s look at some math. One major camera brand offers both a prosumer DSLR model with an APS-C sized sensor and a medium format camera system. To make a side-by-side comparison, let’s take a 10×10 mm square chunk of the sensors of both models.

Massive Denali, at 20,340 feet high the tallest mountain in all of North America towers above Wonder Lake in Denali National Park, AK. © Jerry Ginsberg

The APS-C camera has about 6.4 million pixels in that space, but the much larger sensor holding more than double the total pixel count has just 3.5 million pixels, or just a drop more than half the number of pixels in the same 100 square mm area. Therefore, each pixel can be and is significantly larger. This gives such a large sensor camera the ability to produce a much better RAW capture and presumably a much better finished file.

The bottom line here is that, all other things being equal, the larger the sensor, the better likelihood we have of creating better quality prints and published photographs.

 

Jerry Ginsberg is a freelance photographer whose landscape and travel images have graced the pages and covers of hundreds of books, magazines and travel catalogs. He is the only person to have photographed each and every one of America’s National Parks with medium format cameras.
His works have been exhibited from coast to coast and have received numerous awards in competition.
Jerry’s photographic archive spans virtually all of both North and South America.
More of Ginsberg’s images are on display at www.JerryGinsberg.com
Or email him at jerry@jerryginsberg.com