Full frame sensor size explained: exploit its advantages for pro-quality pictures

Full frame sensor size explained: exploiting its advantages for pro-quality pictures

The rise of so-called ‘entry-level’ full frame DSLRs has brought the full frame sensor size to a whole new audience. But what can a full frame sensor offer your photography that your crop sensor can’t?

In this post we’ll explore some of the myths and pros and cons of full frame sensors and explain how it can affect the different types of pictures you may take. We’ll also look at ways to fine-tune your shooting technique you really use your full frame sensor to its full potential.

We’ve used one of the first ‘entry-level’ full frame cameras, the Nikon D600, and Nikon APS-C sensor cameras for our examples in this article for the sake of clarity. Mixing up each camera manufacturer’s unique nomenclature can get confusing and distract from the overall discussion on full frame sensors. But the same principles discussed below will apply whether you shoot with a full frame Canon DSLR, Sony, Leica or any other full frame camera.

SEE MORE: Camera sensor sizes explained – what you need to know about Four Thirds, 1/1.7, full-frame and APS-C format

Full frame sensor size explained: exploiting its advantages for pro-quality pictures

What is full frame?

 

‘Full frame’ is the term used to describe a camera with a sensor the same size as a 35mm film negative, measuring 36 x 24mm. Most DSLRs, however, use sensors measuring approximately 24 x 16mm.

This is close to the APS-C film format, which is why these are often referred to as ‘APS-C’ cameras. Nikon makes cameras in both sizes, but uses its own nomenclature. Its full frame cameras are ‘FX’ format, and its APS-C cameras as ‘DX’.

Originally almost all DSLRs used the smaller APS-C format. Sensor technology was in its infancy, and manufacturing large sensors was prohibitively expensive.

Over the past few years full frame cameras have become less costly, and while Nikon’s D3, D3s and D3x bore professional price tags, the Nikon D800 and D600 introduced in 2012 cost much less. They’re still not cheap, but they are just about affordable.

SEE MORE: DSLR vs Mirrorless – understanding the key differences

A Nikon full frame sensor

A Nikon full frame sensor

Bigger is better
In the days of film photography, bigger negatives always produced better quality than smaller ones, and the same is true of digital sensors. Nikon’s full frame FX sensors are 1.5x wider than its DX sensors, with an area roughly 2.4x greater. This has an impact on the quality of the pictures.

In general, pictures taken on full frame cameras are sharper, with better fine detail, smoother tones, a wider range of tones and a greater sense of ‘depth’.

As a result, more and more amateurs and enthusiasts will be tempted to upgrade from their DX- format Nikon cameras (or whatever brand you may shoot with) to a full frame model.

While the improvements in quality are relatively easy to demonstrate, there are disadvantages too. DX-format Nikon DSLRs aren’t just cheaper; they are in many ways easier to use and more practical.

SEE MORE: 99 common photography problems (and how to solve them)

Lens loyalties with full frame

The other issue when swapping formats is lenses. Camera bodies come and go, but lenses are a long-term investment. The Nikon D50 you bought years ago may be obsolete but the lens that came will be just as good today as it was then.

Nikon started off making DX-format DSLRs and a whole range of DX-format lenses to go with them. If you do decide to upgrade to the full frame FX format you’ll almost certainly have to invest heavily in new lenses too.

You can use DX-format lenses on FX-format Nikons, but only in ‘crop’ mode. The camera restricts the sensor area to a DX-sized rectangle in the middle, and you don’t get the benefit of the sensor’s full resolution.

For example, in crop mode, the 36-megapixel D800 produces images of 15.3 megapixels, while the 16-megapixel D600 drops to 6.8 megapixels. So, using your DX lenses is not a long-term solution.

Of course, you may have some FX lenses already, like Nikon’s 70-300mm f/4.5-5.6 telephoto zoom, which is a popular choice for DX-format SLR owners but is actually an FX-format zoom.

If you are considering moving to an FX camera in the future, start investing in FX-format lenses now because they’ll work on any DX-format Nikon DSLR in the meantime. Our photography cheat sheet below illustrates the effect you’ll see when you mix and match full frame and crop-sensor lenses. Click on the infographic to expand the file.

SEE MORE: What camera should I buy: pros and cons of each type (and what they’re best at)

Full frame cameras: which lenses can you use?

Focal factors
The other big difference between the DX and FX formats is what they mean for angle of view of your lens. The DX sensor captures a smaller image area, which makes it look as if you’re using a lens with a longer focal length.

If you fit a 50mm lens to a DX camera, the pictures look as if they were taken with a 75mm lens. This is the so-called ‘focal factor’. Photographers also talk about ‘equivalent focal lengths’, but really it’s the same thing.

The focal factor of Nikon’s DX sensors is 1.5, which means you multiply the lens’s actual focal length by 1.5 to get its equivalent focal length.

This can work in your favour with DX cameras. If you have a Nikon 300mm f/2.8 lens fitted to a D7000, for example, it effectively becomes a 450mm f/2.8!

If you then invest in a full frame camera like the D800, your 300mm f/2.8 lens will still work fine (it’s an FX-format lens, after all), but it goes back to functioning as an ordinary 300mm.

There are many things to consider when choosing between the DX and FX formats, then, including practical and technical considerations.

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