Review: Sigma 16-300mm F3.5-6.7 DC OS

This review of the Sigma 16-300mm F3.5-6.7 DC OS was performed in mostly real life conditions with the addition of some studio work to measure the lens sharpness at various focal lengths and apertures.

Video

Gear Acquisition Syndrome

There is a pattern called the Gartner Hype Cycle that I first encountered in the IT industry describing the stages of an IT project moving from inception to maturity. The pattern applies equally well to Photography, specifically to the purchasing of new photography gear and especially to Gear Acquisition Syndrome!

The Gear in question acts as a Technology Trigger, piquing the curiosity and leading inexorably toward a Peak of Inflated Expectations. This is often quickly followed by the Trough of Disillusion, in severe cases a Slough of Despond, which leads in turn to a Slope of Enlightenment and eventually to a Plateau of Productivity or in some cases to E-Bay or the Shelf of Doom.

Let me explain. When we first hear about a new lens that seems like as though it could plug a gap or extend our capability we get excited and start reading reviews. This is the Technology Trigger. Initial reviews are often written by affiliates or client journalists and tend to be uncritical. Our expectations soar towards the Peak of Inflated Expectations and when we get our hands on the said lens, we generally, at least at first, test the capabilities we’ve already seen demonstrated. Hurrah! It works brilliantly and off we go in a giddy whirl of excitement. Several days later we start to notice the shortcomings of the lens. We are entering the Trough of Disillusion.

Sometimes this leads to the selling of the lens or the Shelf of Doom, but if the lens is actually any good, more often we start to work out its strengths and enter the Slope of Enlightenment. Eventually we reach a Plateau of Productivity where the lens is making a positive contribution to our business or simply to our photography in general.

Every lens has shortcomings, but in some lenses the gap between expectation and actuality is dauntingly large. In my career, I’ve only ever known four lenses that performed to my expectations consistently.

• Canon EF 11-24mm f/4L
• Canon EF 16-35mm f/2.8L III
• Canon EF 70-200mm f/4L IS II
• Canon EF 50mm f/1.2L

Every other lens I own or have owned has to some degree disappointed. This is not necessarily the fault of the lens, usually it’s because my expectations have been unrealistic from the beginning.

So we notice the failings and enter the Slough of Despond. The lens goes on a shelf and in extreme cases never gets used again. More usually, we start to use the lens, rediscover its strengths and enter the fourth stage: The Slope of Enlightenment and eventually the Plateau of Practicality where we have made peace with our expectations and can use the new lens to its strengths.

Normally I don’t review lenses, because the logical time to review them is when the lens is new and that coincides with the period that my judgement is most skewed! By the time I’m in the Plateau of Practicality, the lens has ceased to be a talking point. I make an exception for this one though because it has quickly proved to be genuinely useful for me.

The Sigma 16-300mm F3.5-6.7 in the Canon RF fit has been available since May 2025 and although I acquired mine recently my expectations were tempered by the fact that I was comparing it to Canon “L” glass. In my experience, very little survives that comparison!

Sigma 16-300mm F3.5-6.7 DC OS

So what is the unique selling point of this lens? If you hadn’t already guessed, it’s the astounding focal range – from 16mm to 300mm is incredible in a single lens, and given that it’s designed for APS-C lenses and therefore comes with a zoom factor of approx 24-450mm it is easily capable of grabbing a range of shots that would normally take two or even three lenses to capture.

Price

At a price of €700 or £600 this lens is less than half the price of a Canon 70-300mm and has a considerably wider field of view at the wide end.

Weight

The Canon RF mount weighs 625g. Compare that with the Canon 70-300mm L that I have been hauling around the countryside, a massive 1060g, So the Sigma is thirty percent lighter. And does the job of three lenses. I’m half way up the Peak of Inflated Expectations already!

In real life there is another reason to love this lens – Ryan Air and their lunatic cabin baggage policy! If I could put a value on the stress saved by travelling comfortably within the Ryan Air baggage policy, it would pay for this lens several times over.

Widest Aperture

The Canon 70-300mm L f/4-5.6 is a half stop “brighter”. The Canon delivers F/4 at 70mm reducing to f/5.6 at 300mm.

The Sigma gives us f/3.5 at 16mm and f/6.7 at 300mm, so slightly darker at the far end of the zoom than the Canon. At 70mm the Sigma reports f/5.6 as the widest available aperture. Here is the complete table showing how the widest aperture is reduced by increasing the focal length.

16-17mm = f/3.5
18-27mm = f/4.0
27-38mm = f/4.5
39-46mm = f/5.0
47-89mm = f/5.6
90-299mm = f/6.3
300mm = f/6.7

When you digest the implications of this table, you realise this is the first chink in the armour – the Sigma is darker than the Canon across the board. This translates as potentially poor performance in low light, so indoors, dark days, blue hour etc.

Focus

Exceptionally fast paired with my Canon R7 in good light, comparable with the Canon although I didn’t test birds in flight. I experienced significant difficulties in blue hour, which the Canon effortlessly rises above.

Sharpness

At the far end of the zoom and wide, in good light, the sharpness is excellent. Falls off at 180mm in my testing but recovers well.

I ran a semi scientific test to discover the optimum aperture for sharpness across the focal range. I placed a USAF Lens Testing Target on the wall of my studio and shot from the other side of the studio at 16mm, 24mm, 50mm, 100mm, 180mm and 300mm. At each focal length I tested Aperture at the widest available value (it’s a variable aperture lens meaning the widest available value decreases (gets smaller) as the focal length increases). So tests were done at each focal length for f/3.5 (where available), f/7.1, f/11, f/18 and f/22.

I say semi scientific because although the tests showed f/11 to be the sweet spot, I suspect it is actually a one stop range between f/8 and f/11. I should have tested for f/8 as well. The ideal test sequence would have been f/3.5, f/4, f/5.6, f/8, f/11, f/16, f/22. Hindsight is a wonderful thing!

Even with this obvious flaw, it was easy to see that this lens needs a lot of light!

Colour

The colours in the RAW file are a little flat compared to the Canon lens. This is something that can easily be corrected in post processing, so I’m not bothered by that, Canon are well known for their color science.

Here is a Before/After demonstration showing the unprocessed RAW file (after demosaicing) and a copy with basic color adjustment applied.

Verdict

If your requirement is to photograph for social media, then this lens is absolutely right for you. It does the job of three lenses and on a scale of iPhone 16 to Canon L lenses, I’d say this lens is way better than the iPhone 16 and probably about 60% of the way towards the Canon 70-300mm L that I’ve been rather unfairly comparing it with. The Canon lens cost €1500, the Sigma slightly less than half. It would be a strange thing if the Sigma was competitive on all counts!

Weight, focal range, suitability for video, APS-C mount and travel convenience are very strong arguments in favour of this lens, the zoom is perfectly calibrated for video – which is the primary use that I’ll be putting it to.

So for travel photographers, social media managers, influencers, and video makers this lens represents outstanding value for money. It’s robust, weather resistant (not the same as sealed) and a pleasure to shoot with. As a professional landscape photographer this lens doesn’t quite do it for me because lowlight performance is something I need to be exceptional. The Sigma borders on poor in this respect, however it definitely avoids the Shelf of Doom, it’s just too convenient to ignore and has a place in my video bag permanently where it will be paired with the Canon R50v.

If you’re interested in buying this lens, please use the following link – I get a small reward and you pay not a penny more for the lens!

https://sigmauk.com/product/16-300mm-f3-5-6-7-dc-os?ref=chriswright