Gear Photography Video

Small is beautiful: 7 reasons to keep thinking beyond full frame

Using a system with an APS-C, Four Thirds, or smaller sensor can offer lots of advantages… 

There’s a lot of heat around full-frame mirrorless cameras right now – and with the likes of Canon’s new EOS R bodies, Sony’s ever-growing Alpha range and Nikon’s up-and-coming Z Series, that’s understandable. But does it mean that anything below full frame in size is a waste of time? Of course not! 

Just as was the case with smaller-sensored DSLR models battling full-frame back in the day, there are plenty of reasons to invest in ‘crop censored’ mirrorless systems. From APS-C format to Four Thirds, and even 1in sensor models, there’s no shortage of new cameras still coming to market and plenty of dedicated lenses, too. Just check out the recent launches by Olympus, Panasonic and Fujifilm. But what are the benefits of using cameras with smaller sensors? We’ll take a look at a few of them there… 

What’s a small sensor? For the purposes of this article, we’re thinking about APS-C, Four Thirds, and 1in sensors, though basically anything smaller than the traditional 35mm or full frame format. Comparing the size of these sensors and their crop factors which affect equivalent focal length, this diagram shows full frame (1x, 36x24mm) as the largest, then APS-C (1.5x, 23.6×15.7mm), APS-C Canon (1.6x, 22.2×14.8mm), Four Thirds (2x, 17.3x13mm) and 1in (2.7x, 13.2×8.8mm).

Keep it light 

One of the biggest barriers of doing photography is sometimes just picking up all your stuff and getting out there to do it. That’s why the majority of images taken today are on smartphones. If you use a body and lenses weighing several kilos, it’s no wonder that your shots will be less spur of the minute and impulsive. 

Smaller sensors take up less space, need a smaller image circle from a lens, and use less power, meaning that camera bodies, lenses and batteries can be smaller, too. Compare a typical full frame mirrorless body like a 20.1mp Canon EOS R6 at 680g, with a crop-sensored alternative like an 32.5mp EOS M6 Mark II at 408g, and you’re saving hundreds of grams. The same goes for lenses. Remember that larger sensors need lenses that can project a larger image circle, and that means more glass and more metal.

Of course you don’t need to just carry less – with a small sensor system you could just as well carry the same weight and have more lens and accessory options. 

Smaller sensors mean smaller, lighter bodies and lenses, letting you carry less, or take more gear for the same burden.

Keep it stealthy

The benefits of a smaller camera system don’t just extend to easing the strain on your shoulders. A smaller body, combined with modern features like an electronic shutter and tilting screen means you’re a more stealthy shooter, too. Make no mistake, people act differently when confronted with smaller cameras, so even if they see you shooting, they’re less likely to be disturbed than they would with a bigger body, in the same way that no-one takes notice of someone shooting on a smartphone. And just like the size comparison we made above, you’ll also most likely be carrying a much smaller camera bag, or even slipping your camera into your pocket between shots. All this is great for documentary, street or even wedding situations where you want to remain an observer and not affect your subjects’ behaviour. 

With smaller bodies, models like Fujifilm’s X100V, which uses an APS-C sized sensor, make for a less intrusive way of shooting.

Keep it affordable

Sure, there might be full-frame bodies out there that can be picked up cheaper than class-leading APS-C or MFT bodies, but generally buying into a smaller sensor system means you save money. Smaller chips are cheaper to produce, and so are the lenses that sit in front of them. Much like the principles of using smaller kit, lower cost bodies and lenses let you either spend less overall, or pick up more gear for an equivalent price. 

Even though it shares the same Z mount as its full-frame cousins, Nikon’s Z 50 is a mirrorless body with an APS-C sized sensor, making it more affordable, while enjoying many of the same advantages.

Keep it sharp

One of the big advantages that full-frame systems trumpet is that they can produce a shallower depth-of-field than smaller sensors at equivalent apertures. This is true. All other things being equal, a larger sensor will always be capable of shallower results, assuming you can afford the fastest lenses. But remember – there’s two sides to every biscuit. 

Though it’s often seen as a drawback, smaller sensors’ extended depth-of-field means focusing is easier, or at least needs to be less precise, and sharpness is greater throughout the frame. You can argue that a FF sensor produces more detail, but that means nothing if it’s out of focus. You can take advantage of this in anything from regular scenics front to back sharpness, through urban scenes and even in macro shots.  

Shot on a Canon PowerShot G5X Mark II, the smaller sensor means depth-of-field is extended for front-to-back sharpness. © Kingsley Singleton

Keep it fast 

Theoretically, smaller sensors also mean faster performance. Of course there are loads of factors that contribute to the overall speed of things like frame rate and AF acquisition, but a lot of them are linked to the sensor size, and specifically to how fast the information gathered by it can be read. Full-frame cameras sometimes use this fact to squeeze a higher fps out of their sensor by cropping its view.

So long as they have the processing power to match, smaller sensors can give faster frame rates as readouts are quicker. © Kingsley Singleton

Keep subjects filling the frame

When you’re trying to capture distant subjects, big sensors can be a disadvantage. It’s the opposite with smaller chips, and actually, the smaller you go, the easier it gets, while full-frame bodies need ever larger and heavier lenses to fill the frame at the same distance. That’s why many astronomical cameras use smaller imaging chips. 

You can see this by mounting the same focal length lens on cameras with different sized sensors. Of course to do this, the mount will need to be the same, as it would be in the case of Nikon’s Z mount or Sony’s E mount, or to use a mount converter. For instance, a 200mm lens on a full-frame Sony A7R IV will have a much wider field of view than when twinned with a Sony A6500, with the 1.5x crop factor of that camera’s sensor giving an equivalent view of 300mm. In actual fact, the lens isn’t magnifying the subject any more, it’s just that a smaller section of its image circle is being recorded. 

This translates into longer lenses being much lighter on crop-sensor bodies, and the benefit is even more pronounced when shooting with 1in sensor compacts like Sony’s RX10 IV, which gives you an equivalent of 600mm at its long end – all in a package weighing only 1095g. So, if you’re into wildlife, sports or shooting the heavens smaller sensors can be well worth a look. 

Shot with a 70-200mm f/2.8 lens, Nikon’s DX sensors give a 1.5x crop, so subjects appear enlarged. © Kingsley Singleton

Keep it moving 

Of course, smaller sensors also have advantages for video. Just look at the popularity of Panasonic’s GH series and its award winning video specs, or the smaller chips used in pro-spec camcorders and drones. Using smaller sized sensors, their chips require less cooling, and don’t overheat as readily larger sensors, all the while typically pushing out faster frame rates, like 60p in UHD and DCI footage. Being smaller and lighter, they’re also easier to use on accessories like gimbals, or when mounted on drones.  

The Panasonic GH5S has a 10.3MP multi-aspect CMOS MFT sensor specifically designed for video and gives oversampled DCI/UHD 4K footage at up to 60p – something that most full-frame cameras can’t match.