Conclusion

The Sigma 90mm F2.8 DG DN is a super-sharp, very well built, short-telephoto prime lens that is surprisingly small and surprisingly affordable.

Its main selling points are undoubtedly its combination of small size with telephoto focal length, superlative build quality, vintage feel and its uniqueness within the Sony system - we can't think of any other 85mm or 90mm prime lenses that are quite as compact as this one.

Following in the footsteps of the other I-series lenses, the Sigma 90mm F2.8 DG DN is an incredibly well-built lens considering its mid-range price-tag,

From the weather-proof all-metal construction to the incredible attention to detail, such as the beautifully damped aperture and focus rings, ribbed lens hood, and the clever, and free, magnetic lens cap, it's clear that Sigma have lavished a huge amount of time and love on this lens.

A traditional aperture ring is a feature that we love on any lens, and Sigma's implementation of it on the 90mm F2.8 DG DN is nigh on perfect.

It has a lovely action, positive enough movements between the 1/3rd aperture stops, and a pronounced gap between f/22 and the Auto setting so that you can't inadvertently select it.

The only thing that we would have liked to see is a way of de-clicking it for video use, but then this is true of all the I-series lenses that Sigma have released so far.

The stepping motor auto-focus system is virtually silent, satisfyingly, quick, and almost 100% reliable.

This lens is a great performer optically, being pin-sharp throughout virtually all of the frame, even when shooting wide-open at f/2.8.

Vignetting is a little heavy wide-open, but chromatic aberrations and pincushion distortion are well-controlled in the JPEGs (although Raw files are another matter entirely) and the bokeh is quite appealing considering that the maximum aperture is only f/2.8.

The Sigma 90mm F2.8 DG DN doesn't really have any obvious rivals, no mean feat in such a crowded camera system as Sony full-frame.

There's the Sony FE 90mm f/2.8 Macro G OSS, but that's a specialist macro lens that is much bigger and heavier than the comparatively tiny Sigma 90mm.

The excellent Samyang AF 75mm f/1.8 FE is also worth considering, but it doesn't quite have the same reach.

Finally, the Sony FE 85mm f/1.8 is similarly priced and slightly faster, but it's also bigger, heavier, not as sharp, and doesn't focus as closely as the Sigma 90mm.

Overall, the new Sigma 90mm F2.8 DG DN is a great addition to both Sigma's I-series of lovely prime lenses and more generally to the Sony E-Mount system as a whole. It offers something unique without also forgetting to be a great lens in its own right.

Ratings (out of 5)
Design	5
Features	4.5
Ease-of-use	5
Image quality	4.5
Value for money	5