Sigma 28-45 F1.8 ultra-wide-aperture zoom (Patreon)

Sigma has recently announced a 28-45 DG DN F1.8 ultra-wide-aperture zoom lens. I won't be reviewing this lens, but I thought you might like to hear my opinion about the relative merits of this lens. There are of course other ultra-wide aperture zooms such as the Tamron and Samyang 35-150 F2-2.8 lenses and I suspect there will be a trend for manufacturers to release more of the 'heavyweight' lenses.

I should start by saying that I like many of the Sigma lenses, and I own three of them (two APS-C lenses and one full-frame lens), and I have reviewed the 90mm F2.8 DG DN lens. I have no commercial affiliation with Sigma so had to purchase these lenses at full price. As I get many of my Sony lenses as part of my Ambassador contract, you can see I would have to have liked these three Sigma lenses a lot in order to purchase them at retail price.

 

By all accounts this new Sigma lens offers very good optical and good AF performance. So what's not to like?
Well ...it's large, heavy and its zoom range is quite narrow. A 28 to 45mm focal range gives it a 1.6x Zoom. I own the FE 35mm F1.4 GM, FE 35mm F1.8 and FE 35mm F2.8 ZA. The largest and most expensive of these 3 prime lenses is the FE 35mm F1.4 G Master lens and it weighs in nearly 1 lb (425 g) lighter than the Sigma zoom. My Sony FE 24-50 F2.8 G compact zoom is much lighter, smaller, and cheaper than the Sigma lens and I own a 20mm G and 55mm ZA F1.8 primes, for the times I need a wider F1.8 aperture.

Not only is the FE 35 F1.4 GM smaller than the Sigma, but it also has a wider maximum aperture and is cheaper than the Sigma. The corner performance of the Sony will, by all accounts, outshine the Sigma at maximum aperture. This is only to be expected when comparing a premium prime with a zoom.

The Sigma lens appears to suffer from focus breathing, as does the 35 GM, but the late model Sony Alpha cameras support 'focus breathing compensation' - but only for Sony lenses.

The Sony 35mm F1.8 is less than 1/2 the price and less than one third of the weight of the Sigma zoom and does not suffer from focus breathing, and has therefore become a popular lens for videographers using older model alpha cameras (those that pre-date focus breathing compensation).

ZOOM vs PRIME

The big attraction of this wide aperture Sigma zoom lens, for many photographers, will be the fact that this is a zoom lens with an aperture as wide as those found on prime lenses (but not as wide as those found on G Master primes).

If you have watched my Lens Choice 2 Patreon seminar, you may remember me showcasing the fact that when working with a prime lens you can 'zoom with your feet', in most instances where your subject is in the foreground. The distance you have to walk to create the same framing, when using 35mm or 85mm primes, is just 1.5 steps forwards or backwards to create the same head-and-shoulders framing. Zooms are of most value when you can't move, or your subject is not in the foreground (rare in most of the events I cover). I usually don't miss a zoom at all if I am working with two camera bodies and two different focal length primes, e.g., a 35 and 85mm primes. I then just zoom with my feet to cover the compositions between these two focal lengths. In landscape shoots I might switch to using 20 and 85 primes. At events where I am prevented from approaching some of my subjects, I might switch to using 35 and 135mm primes. I cover this topic in my 'Two from Four' section in my Lens Choice 2 seminar.

The distance you have to walk forward, when using a 35mm prime lens rather than using a lens you can zoom to 45mm (the maximum zoom of the Sigma 28-45), is just half a step.

If something is preventing you from walking forward you can, as an alternative option, crop tighter in post-production editing, to achieve the '45mm equivalent 'composition . If you were using a camera with 60 megapixel sensor the resolution would drop to a very respectable 36 megapixels. You would also have to apply the 1.285x crop factor to the aperture to determine the equivalent depth of field, but this drops from F1.4 to just F1.8 (same as the maximum aperture of the Sigma 28-45mm F1.8 lens).

If you are using a camera with a 33 Megapixel sensor the resolution would drop to 20 Megapixels (more than enough to fill a 4K screen with a resolution of 8.3 megapixels). In many respects our high-resolution sensors give us a zoom capability like never before. We even have 'Clear image zoom' for JPEG shooters, and when shooting movies, which sort of negates the usefulness of a zoom lens with a 1.6x zoom range (such as the Sigma 28-45).

If you are looking to achieve the same framing of the 28mm focal length, when using a 35mm prime, you are going to have to take 1/2 step backwards when using the prime lens instead of the zoom.

CONCLUSION

The 28-45mm lens is a bold move by Sigma, and it might just find some very happy customers who are not put off by the size and weight, but I would personally prefer to work with one of my lightweight 35mm primes or a 'compact' zoom such as the Sony FE 24-50mm F2.8 G - a lens that I can carry attached to a camera using a wrist strap, and work all day without the weight becoming a burden.

For more on the subject of 'Lens Choice', check out the Lens Choice seminar, the Lens Recommendations section in your camera-specific eBook and the Travel 2023 Seminar, New Era Dawns and Mighty Mekong seminars (all available on the Premium and Premium Plus Tiers)

Go to https://www.patreon.com/collection/34689?view=expanded

If you would like to discuss this topic in greater detail, join me on the June Q&A forum (available for Premium Plus members). Remember you can switch to a higher Tier for just one month if you need to access support that is not available on your current Patreon tier.

Mark Galer