Customer review: Sigma 24-70mm f/2.8 Art VS Sony 24-70 f/2.8 GM

The new Sigma 24-70mm 2.8 Art has my interest because for my Sony A7R II, I like a bright standard zoom. It seems like an affordable alternative to the GM lens. So quickly responded to BudgetCam's Review mail. My suggestion to review the Canon version on my MC-11 adapter ring (specifically to use Canon Art lenses from Sigma on Sony E mount) against the Sony 24-70mm 2.8 GM falls well (the MC-11 has been updated to the current version 1.10 at the time of writing). 

Meanwhile, there have been a number of tests and reviews that show that the Sigma really is a bit inferior to the Canon and Nikon alternatives this time around. But it remains interesting what differences stand out in everyday use. For those already fed up with this Review: it's not too bad.

The disclaimer: with this Sony Camera, I myself use mostly manual-focus Lenses from Olympus, Zeiss and Leica. For AF I have Olympus M43, and its 12-40mm 2.8 (24-80mm in Full frame) is a nice lens that I use a lot. That also partly determines my expectations about the reviewed Lenses. In the Sony AF system, I am just starting to become a bit at home and am orientating myself towards ‘native’ Lenses for the Sony. I've rented the Sony GM lens for a shoot before, and I was happy with the results then. Much of that was at high ISO, so it wasn't a very informed judgement.

Weight and size

These are not small or light Lenses. I hate to admit it, but after a day of taking these two Lenses out with another one and a half old Olympus lenses for reference and a Tripod, I felt all kinds of muscles I didn't know I had. By then, you have a sloppy 5 kg hanging from your shoulders.

For reference, I ran my Olympus OM Zuiko 35-80mm 2.8 with it. My Full frame ‘standard zoom’ that I am very happy with. You also see immediately what we have advanced over the past 25 years, at least in terms of zoom range. For comparison at 24mm, I used the Olympus 24mm 2.0.

Having used the Lenses in rotation, I don't think the difference is super big. The Sony is slightly lighter and you feel that when you have them both in your hands. But if you only have one of these Lenses? With Camera, the Sigma combo is about 15% heavier than the Sony, 250 grams. Now that I know, I think it's a lot of grams, but I doubt the difference is noticeable in daily use. Remains very personal, of course, so when in doubt: rent them together for a weekend ;-). To be honest, I find them both irritatingly heavy after a while around my neck. I use an ordinary neoprene strap, so maybe we should see if we can make it more convenient....

Feeling in use

Both Lenses are just a bit too thick for someone with not too large hands like me to comfortably support and zoom or focus at the same time. I would if you have small(er) hands definitely try them out before buying either of these Lenses. The biggest difference I found was the location of the zoom ring (which you use most often on an AF lens anyway). On Sony it's on the camera side, on the Sigma at the back. I prefer the Sony order. Especially because I sometimes manually adjust the focus (in this test, too, I found out that AF is not always right the first time), and then reaching forward without looking is more convenient than reaching back. You also run less risk of touching the set distance again when zooming. But there again: all based on my ‘muscle memory’. So feel it yourself.

The tilt point is quite close to each other on all three Lenses, 3-4 cm from the Lens mount. That wasn't too bad, I had expected the Sigma to be further away from that because of the Adapter (and the Olympus too). At the 70mm position, the tilt point also shifts less than I thought, about 1.5 cm on all three, I think. How the tilt point shifts is shown by a red line on the top Photo.

Autofocus

Well, a lens with an Adapter will always focus a bit slower than a ‘native’ lens anyway. That was my expectation, and it was right. Somewhere I had a plan to make a short film, but it never materialised. Two days is also a bit short for a Review, I now know.

Sony's eye-recognition Autofocus, a comfortable tool for portrait photography, does the trick with the Sigma combo. Maybe slightly slower, but not distracting. In a test at night in low light, the Sigma does fail earlier than the Sony. But by then, it is not always reliable either. Funny thing is that the eye and face recognition works down to lower light levels than the AF. You see the squares in the viewfinder, but focusing ho but.

In terms of controls, a Canon photographer friend also remarked that the zoom ring turns heavily. I have heard that from Canon users before, when they use another brand of lens. Personally, I prefer it to be a bit stiffer than that it changes at the slightest touch (or ‘sags’ around your neck). The Sigma's AF on his Canon 6D performed just as fast as his ‘native’ Canon 24-105mm, by the way.

Pixel peeping

Back to Lenses. At the Uithof, I found a nice test wall.

All lenses were focused by hand, at maximum viewfinder magnification. Camera on tripod, photographed in RAW, exported with Lightroom's default settings except where indicated. No lens corrections or lens profiles selected. Unfortunately, you can't tell much from the darkness of the Photo. It was constantly changing overcast; then full sun, then a thick cloud and everything in between. By the way, I am also taking these pictures for the first time, so don't compare them directly with those taken by experienced testers ;-).

At 24mm, the Sony is clearly sharpest at f2.8 in the centre. The Sigma is still out of focus at f4, at f5.6 almost. The Olympus is blurrier at f2.8 and f4, at f5.6 it hangs around but at f8 the Olympus still seems to improve while the zooms are past their prime by then. At the edges, the Sony is superior.

[The centre Photo is overexposed by one stop]

At 35mm, it is more equivalent in the centre than at 24mm. Still the Sony is sharpest at 2.8-5.6, but the differences are smaller. At the edge, the Sony remains superior.

[The centre Photo is overexposed by one stop]

At 50mm, the differences have narrowed a bit more. At 2.8 and 4, the Sony is still sharpest in the centre, after that it depends (actually, I think the Olympus is sharper there). At the edge, the Sony is also best at 2.8 and 4, at 5.6 and 8 I see little difference.

[The centre Photo is overexposed by one stop]

Finally, at 70mm, the Sony seems past its prime. The Sigma is now sharper, closely followed by the Olympus. Also, the Sony's edge is no longer the best, which is now the Olympus.

[The centre Photo is not overexposed]

Blur

Part of the charm of full-frame is, of course, the easier to get blur in your photos. Beautiful blurred points of light are often a good indication of the overall ‘bokeh’. Lenses with aspherical lens elements sometimes show rings in those points of light. With these Lenses this is not so bad. There is some texture, but no noticeable rings. The Sony has a blue rim around the light points, the Sigma more orange. Ticking chromatic aberration removal or enabling the lens profile in Lightroom does not help, by the way.

[Taken out of hand, so that's probably where the differences come from. Below left are the full shots in miniature.]

This is what it can look like during the day:

Conclusion

The Sony leaves the better overall impression, but the Sigma seems better in the telephoto range. I did not do any further testing to find the tipping point.

On a Sony A7R II Camera with MC-11, this Sigma does have some major problems compared to the GM lens. Heavier, slower and predominantly less sharp. My conclusion is that the Sony is well worth its substantially higher extra price (but in terms of rental it's not too bad ;-) with that. Whether you want to spend the money on it is of course an entirely different question. After all, good is often good enough. It is also questionable whether these differences are as obvious on sensors around 24Mp. And if you shoot with both Canon and Sony, this Sigma is also a logical choice.

Perhaps somewhat surprising for some people: if you can live without AF and change Lenses a bit more often, you can still get fine results with an older lens on the Sony. You will then have to make a clear sacrifice on edge quality, and to a slightly lesser extent on centre quality. As can be seen, and this applies to most older lens designs, lens flaws are somewhat less corrected, and vignetting towards the corners is also often greater with older zooms. Lightroom does have options to correct lens errors, and they help. But for this test, these were not ‘on’.

Photo gallery

Some more photos to conclude, edited to taste in Lightroom. They are, like the lens comparisons above, in full resolution in this Flickr album. Often taken with both Lenses.

Wondering how you like the Sigma 24-70 f/2.8 Art? Rent it directly from Budgetcam, it is available with a Nikon or Canon mount. Would you also like to write a Review on the latest equipment? Then sign up for the Budgetcam review pool.