A look into why sensor sizes are important, and how they can improve the quality of your images.
If you’ve been wondering why some camera models are so much more expensive than others, when even mobile phones are offering 20 and 30 MP cameras, the answer lies in the sizes of their sensors. But before we look into that, let’s take a look back to the film sizes of yesteryear. The 35mm film as we all know was pretty much a standard film size before digital took over. Apart from this, the 110 was an even smaller size, while the 120mm was a medium format film that was many times larger than the 35mm. And then the view cameras used a 4 x 5 inch sheet film (and they still do). Some view cameras even use 8 x 10 inch film!
The most obvious advantage of a larger film size was the fact that it needed less enlargement compared to a smaller film size, clearly making sharper and better quality prints when compared to a smaller film. However, when enlargement wasn’t a factor, the difference in quality was less apparent. Advertising photographers who used to shoot film for giant ad hoardings would prefer the 120 or 4 x 5 size over the 35mm…for this reason. Apart from this, there is also an apparent difference in the depth of field that a lens produces. On a larger film, there is also a larger area that is out of focus, making it appear as if the depth of field is a little shallower compared to a smaller film that renders the same angle of view. Without getting into more technicalities, it simply means that the larger film size produced an image that clearly showed more of an apparent difference between the sharp and ‘unsharp’ areas, and this is usually preferable to having more of an area ‘in focus’. It is the same with a digital camera with a larger sensor.
With digital, camera makers are today able to pack more and more pixels into a small sensor area, which allows for much larger prints to be made when compared to the digital cameras of even a few years ago. This allows for a small sensor to make large prints, something that a small film size was not so good at! However, the optical difference between a larger sensor and a smaller sensor is still comparable to let’s say a 120 film producing higher quality output than a 35mm. Today’s professional ‘standard’ sensor is the ‘full frame’ sensor and it is the same size as a frame of 35mm film. Entry level cameras use a ‘crop sensor’ which is cheaper to produce, but can still have enough mega pixels to produce very large prints. The ultra professional cameras such as the Hasselblad or Phase One have a ‘645’ sensor, which is the same size of a 645 film (which is about half the size of a 120mm frame).