Different formats have different strengths and weaknesses, generally offering a different balance of size, price and image quality. But they can only live up to their full potential if they have lenses that let them deliver the size or price benefits they should be capable of.

For various reasons that have very little to do with the merits, or otherwise, of APS-C, most of the biggest camera makers have heavily focused their lens development on full-frame. This has left us in the odd situation where Canon, Nikon and Sony all make some quite nice APS-C bodies, but with lenses for them being distinctly few and far between.

But, as was the case in the DSLR era, third-party makers such as Sigma and Tamron have helped fill the gap. And, refreshingly, for the most part, the big camera makers have let them.

Finally, with the arrival of Sigma’s new 75-180mm equiv zoom, APS-C users across multiple systems can put together some pretty flexible kits that take full advantage of the size, price, image quality balance that the format should be able to provide.

Richard Butler

Incrementally, the choice of compact primes for APS-C has expanded, with autofocus options from the likes of Sigma, Tokina and Viltrox spanning a wide range of focal lengths. In terms of zooms there are a choice of wide-angles, and both Tamron and Sigma offer some interesting fast standard zooms

Even the camera makers themselves seem to recognize this need, with Nikon, Sony and Fujifilm all offering 16-50-ish F2.8 options. And, collectively, these options will cover a wide range of photography situations.

The addition of a modern approximation of a 70-200mm equiv for APS-C rounds out this lineup. It means you can keep your kit small and relatively affordable across an even wider range of photography. And it’s hard to convey just how small the Sigma 50-120mm is, until you see it in person.

Obviously, a 50-120mm F2.8 is not fully equivalent to an F2.8 75-180mm lens on full-frame (120/2.8 ≠ 180/2.8), but it lets you do the things that make a 70-200mm lens on full-frame so popular, while maintaining the size and price benefits you get in return for the image quality trade-off.

I loved the original APO Sigma 50-150mm F2.8 EX II HSM in the DSLR era because it was two-thirds the size of a 70-200 and two-thirds the price. It was a much easier to handle and less potentially intimidating lens than a 70-200, helping give me the confidence to shoot some of my first public portraits. And it was much easier to carry than the second-hand 70-200mm F2.8 I’d previously bought and that sat at home unless I was absolutely sure I’d need it.

Richard Butler

The new Sigma not only repeats that trick but improves on it. It’s so much smaller and lighter than an actual 70-200mm lens (even compared with Canon’s RF 70-200mm F4 with which it’s approximately equivalent) that it means I can keep it with me, even if I’m not anticipating needing it.

So, APS-C users, you have a choice: you can believe the bottom-line-benefitting talk of ‘upgrade paths,’ and saddle yourself with a heavy, expensive 105-300mm equiv lens (which can have their uses, but that aren’t necessarily the same as those of a 70-200mm), or you opt for the Sigma, and gain approximately 70-200 utility in a lens you can fit in a coat pocket. As an APS-C shooter, I know which makes sense to me.