One of the biggest questions which is asked when buying cameras is about the sensor size. It matters, right?… right? Well – maybe yes, maybe no, maybe both. Having first shot with an APS-C sensor before moving onto full frame, then shooting with APS-C again, then full frame again, and then now Micro Four Thirds, I realised that it did not matter as much as I thought it would. Not for my use case in any event. And that is the key factor to deciding whether sensor size matters or not – the use case. Not simply the technical details about sensor sizes and pixel density.

When someone asks me what camera or lenses they should look into getting, my first response is always a question back to them – what do you intend to do with the photographs you take? For example, if all you are going to do with the photos is to post on Instagram, then my suggestion would be not to even get a camera, but to invest in a better smartphone that has a better camera. Instagram compression and with content on Instagram generally being consumed on a smaller phone screen rather than a computer’s 8K monitor means any benefits in image quality you could get out of an actual camera vs a smartphone camera would be negligible. Not to mention the extra steps in your workflow in having to get the photos from the camera to the phone to then upload – and that’s assuming you’re not shooting in RAW which means you need to do some editing too.

Traditional wisdom would suggest that you should use a full frame camera when shooting the night sky, and whilst, yet, the image quality is better, it does not mean that crop sensor images are not good enough for what you need.

Unless you are printing huge posters or wanting to enjoy the details reproduced at a pixel level, a good Micro Four Thirds or APS-C image will still look fantastic. Most people will not notice the difference, especially once it’s been compressed and shared online, or even printed up to a reasonable size. What they will notice is whether the composition is interesting, the colours are compelling, and the overall mood hits the mark. These elements matter more to the final image than the technicalities of your sensor size.

Whilst I have only mentioned image quality, a benefit of smaller systems is that, generally, the lenses are smaller – even if the OM-1 Mark II body I use is comparable to other full frame mirrorless bodies (the Micro Four Thirds Panasonic Lumix G9 II flagship used the same body shape as the full frame Panasonic Lumix S5 II). Smaller lenses mean less glass and in turn this means that they are lighter. This is something that I came to appreciate only after lugging full frame bodies and heavy lenses on trips abroad. When you are carrying several kilograms of gear around for hours, suddenly the promise of “better image quality” starts to feel a lot less appealing. Moving to Micro Four Thirds meant I could fit an entire system – camera body and multiple lenses – into a small sling bag and still have room to spare. I am of course ignoring the interchangeable full frame system which is small in footprint, with small lenses – the Leica M ecosystem. Yes, the Leica M bodies and lenses have a small footprint, but they are manual focus only and does not come with all the bells and whistles as modern mirrorless bodies.

It is easy to get swept up in the specs. Marketing departments love to throw around terms like “larger sensor” or “more megapixels” as if they’re magic bullets that will instantly level up your photography. But photography is not about specs. It is about storytelling. I have taken some of my favourite images on cameras that would now be considered outdated or entry-level. I have even used an iPhone 11 to photograph an entire assignment for a online news platform to accompany an interview which my friend was conducting.

I am not saying that there is not a place for the full frame cameras. But it all depends on the use case as to whether it is necessary to have a full frame body and all the associated heavier, bigger, and pricier lenses. If you are into portrait photography and love blurry backgrounds, then it may be a full frame body has to be your weapon of choice. Taking into account conversions for focal length and aperture, to get a similar field of view and depth of field, a 50 mm f/2 image on full frame like below would require a 25 mm f/1 on Micro Four Thirds.

Whereas if you like to take environmental portraits which has the environment and background less blurred, a full frame field of view and depth of field of around 35 mm f/8, when you only need a 17 mm f/4 lens in Micro Four Thirds.

And let us not forget that the technology of cameras has come a long way since the days when I was shooting with my Nikon D40 in the late 2000s. Sensor technology has improved so much that today’s Micro Four Thirds or APS-C sensors often outperform full frame sensors from a few generations ago. If old full frame DSLRs were good enough then, the modern crop sensor offerings should be good enough now.

So does sensor size matter? Yes. But only if it matters to your style, your subjects, your needs, and your preferences. It is one of many tools in the toolbox and not the be-all and end-all of photography. For me, having seen how the Micro Four Thirds system can be used to capture the aurora and the cosmos from my trips to Yellowknife and the Finnish Arctic, I very much value the freedom, weight savings, and versatility that my OM-1 Mark II can offer over the marginal gains in image quality at the price of carrying around a full frame rig. For someone else, that trade-off might look different. And that is totally fine. The best gear is the one that helps you create your best work, whatever that means for you. For me, it just means a focus on being able to easily bring my gear here and there, and without taking too much space in my carry-on bag for flights.

At the end of the day, the most important thing is to know your gear well, understand what it can and cannot do, and then just get out there and use it.