Sigma 90mm F2.8 DG DN Review
The Sigma 90mm F2.8 DG DN is a fast, short-telephoto prime lens for Sony Alpha full-frame and APS-C E-mount mirrorless cameras, where it provides a 135mm equivalent focal length. It's also available for Leica / Panasonic / Sigma L-mount cameras.
This new lens is part of the Sigma I series of compact, high-performance, impeccably constructed primes for mirrorless camera systems, which boast a premium all-metal weather-sealed construction, a magnetic metal lens cap and a metal lens hood.
The Sigma 90mm F2.8 for Sony was launched in September 2021, joining the Sigma 24mm F3.5 DG DN, 35mm F2.8 DG DN, 65mm F2.8 DG DN and 45mm F2.8 DG DN lenses as well as the new 24mm F2 DG DN that we've recently reviewed.
It features 11 elements in 10 groups, with one aspherical element and five special low dispersion elements to reduce chromatic aberrations and color fringing.
There's a Super Multi-Layer Coating to minimize internal reflections so that flare and ghosting do not occur.
This lens boasts a dust- and splash-proof structure and has a minimum focusing distance of 50cm / 19.7in. with a maximum magnification of 0.2x.
It has a rounded 9-blade diaphragm which creates an attractive blur to out-of-focus areas of the image and an internal focusing mechanism which means the lens barrel doesn't move.
There is a stepping motor for fast, quiet and precise auto-focusing, while the focusing ring provides fine manual focus control.
A traditional aperture ring runs from f/2.8 to f/22 in third-stop increments with an Auto setting also available for camera-based aperture selection.
The Sigma 90mm F2.8 DG DN lens is available now priced at £549 / $639 in the UK and USA, respectively.
Ease of Use
Weighing in at 295g and measuring 64mm × 61.7mm, the all-metal bodied Sigma 24mm F2 DG DN is both incredibly light and incredibly small for a 90mm full-frame lens.
Its overall size is very well-suited to a camera like the Sony A7 III that we tested it with, as shown in the product photos.
Even with the supplied hood attached, it is still amazingly discrete for a 90mm lens.
Most 90mm optics are usually specialist macro lenses, such as the Sony FE 90mm F2.8 Macro G OSS, which is over twice the weight and length than this Sigma 90mm.
Whilst you don't get the same macro capabilities with the Sigma 90mm F2.8 DG DN, having such a long focal length in such a small package makes it pretty unique, no mean feat in what is now a very mature camera system with lots of avaulable lenses.
Build quality is simply superb, far exceeding what you might expect from a mid-range, f/2.8 prime.
Sigma have really gone to town on the new I series, so much so that they've explained in great detail just how much thought has gone into it.
It incorporates a brass bayonet mount that's supposedly more durable than a normal metal mount.
A rubber seal is incorporated into the lens mount's design to make it dust- and splash-resistant.
The Sigma 90mm F2.8 DG DN lens has a metal lens mount and it accepts common 55mm filters via metal threads on the front of the lens.
The lens doesn't feature built-in optical image stabilisation, relying instead on the camera body's stabilisation system.
The Sigma 90mm F2.8 DG DN lens has a generously wide, ridged motor-assisted focus ring that is very nicely damped. Manual focusing is possible by using the focus mode switch to toggle between AF and MF.
There are no hard stops at either end of the range, making it a little more difficult to set focus at infinity. Polariser users should be pleased that the 55mm filter thread doesn't rotate on focus.
The Sigma 90mm F2.8 DG DN lens utilises a stepping motor which produces quiet, but not silent, smooth focusing, making it fairly well-suited to shooting both stills and video, with the overall lens length remaining constant during focusing.
When it comes to auto-focusing, it proved to be a quick performer on the Sony A7R III camera that we tested it with.
We didn't experience very much "hunting", either in good or bad light, with the lens accurately focusing almost all of the time.
Sony's near flawless Eye AF works perfectly with this lens, quickly locking onto and tracking the subject's eye despite the wide-angle view, and it fully supports Sony's DMF and AF+MF shooting modes.
The Sigma 90mm F2.8 DG DN lens features an aperture ring that has 1/3EV stops ranging from f/2.8 to f/22 and an Auto setting if you prefer to set the aperture via the camera body.
Sadly there's no Click switch on the lens barrel that lets you de-click it for silent operation during movie recording.
The Sigma 90mm F2.8 DG DN lens isn't supplied with a lens case, but it does come with a very good quality, hybrid plastic and metal, circular lens hood (LH576-02) that continues the ribbed texture of the lens barrel, and also an innovative magnetic metal lens cap (LCF62-01M), in addition to a normal plastic cap.
This dedicated metal cap clips to the front surface of the lens magnetically, and there's even an optional magnetic metal lens cap holder (CH-11) that can be clipped to a bag or a belt.
Note that the magnetic lens cap can't be used with filters and is quite awkward to use when the lens hood is fitted.
The 90mm focal length provides an angle of view of 27.0 degrees on a 35mm full-frame camera.
Chromatic aberrations, typically seen as blue or purple fringes along contrasty edges, were not very apparent in our test shots, only appearing in very high contrast areas. The example below show the worst-case scenario.
With the lens set to its maximum aperture of f/2.8, there is some light fall-off in the corners, requiring you to stop down by at least 3 f-stops to completely prevent it.
There's very little distortion evident in the JPG files - the Sony Alpha A7 III automatically and successfully applies corrections to them - but the Raw file suffers from lots of pincushion distortion that you'll need to correct in post-processing.
The Sigma 90mm F2.8 DG DN is capable of producing quite nice sunstars when stopped-down to f/16 or f/22, as shown below.
The lens is a little susceptible to flare when shooting directly into the sun, though, even with the supplied lens hood fitted.
The Sigma 90mm F2.8 DG DN isn't claimed to be a macro lens, but it does offer a minimum focusing distance of 50cm / 19.7in. with a maximum magnification of 0.2x. The following examples demonstrate how close you can get to your subject.
Bokeh is a word used for the out-of-focus areas of a photograph, and is usually described in qualitative terms, such as smooth / creamy / harsh etc.
In the 90mm F2.8 DG DN lens, Sigma have employed an iris diaphragm with 9 rounded blades, which has resulted in very appealing bokeh for a short telephoto lens.
We do realise, however, that bokeh evaluation is subjective, so we've included several examples below for your perusal.
In order to show you how sharp this lens is, we are providing 100% crops on the following page.