Is there a difference between the Leica and Sigma 24-70mm zooms?

The new Leica and Sigma 24-70 zooms are suspiciously similar, apart from the obvious cosmetic differences. But what about performance and optical quality? Many readers will have been wondering about this before deciding which version to buy.

The price difference is dramatic. The Sigma f/2.8 DG DN Art, at £1,050, is well under half the price of Leica’s Vario-Elmarit-SL 24-70 f/2.8 ASPH at £2,300. And the specification is very similar, as I explained last month. Both lenses are probably made in the same factory.

Comparison

David Crewe of PetaPixel took the opportunity to try both these lenses side by side, and the results show remarkable similarity in optical performance. However, one significant difference he did notice was in autofocus speed. Used on the SL2, the Sigma was noticeably slower to focus than the Leica. As he says:

…if for example, an autofocus task were to take 0.5 to one second to lock on to an object with the Leica lens, the Sigma lens would take 1.5 to 2.5 seconds in the identical situation. This behavior was consistent regardless of the environment or lighting.

He also found that the SL2 was slower to initialise with the Sigma than with the Leica. It helps that the Leica camera applies the correct lens profile, and this is important. These aspects could make the Vario-Elmarit a more sensible choice for the Leica owner, although lens corrections can easily be applied in post-processing.

However, I believe these differences could well be eradicated by software update. Significantly, there is little to choose between the lenses in terms of optical performance and, that is the paramount consideration.

It’s early days yet, and it would be interesting to see this comparison between the lenses repeated on a Panasonic S5 or S1.

Conclusion

So which to choose? The difference in AF speed could well be the deal-breaker. If a software update cannot correct it, that does make a case for spending the extra on the Leica. But most of the differences were subjective. As David says:

While the Sigma lens may have a few additional features with the AF/MF switch and button, the lenses have basically the same performance. Optically speaking, the images are nearly identical with only very subtle differences when shot at the lens’s respective focal and aperture extremes, so you won’t be making a bad choice either way. In the end, you’ll just have to make your decisions based on personal preference, the intended use of the lens, and how much you want to spend.

Have you tried either of these two lenses and can you add more to the discussion? The Sigma is definitely a bargain, but will you be happy with it? Would you regret not spending over twice as much on the Leica design and branding?

Via PetaPixel

Postscript 21/6/21: A source in Germany has informed us that dealers have been told that the Leica 24-70 is based on the Sigma but that two lenses have been exchanged to improve the image quality.



20 COMMENTS

  1. It occurs to me that the autofocus speed difference is probably down to software and that the Leica firmware is tuned more to speed than Sigma’s default.

    It would be interesting to get one of these Sigmas on their docking station to see what can be achieved as a number of factors can be customised there by the user as well as the firmware being updated.

    • I think this is almost certainly the case. I doubt there is any physical reason for differences in autofocus speed.

  2. I’ve used my 28-70 a bit now (Sigma version). It is a fine lens of convenience. I think that’s the whole point of it – a smaller, lighter version of the (probably) better 24-70 Sigma/Lumix lenses. I’m sure the Leica version 28-70 would feel more “substantial”, but it would lower that “convenience factor” for me.
    I guess the Leica 24-90 is the gold standard, both in optical qualities and shear mass, and for Leica, their version of the 28-70 IS lighter and more “convenient” by companion.

  3. Also how would Red Dot know if Leica has better quality control than Sigma – I guess they might have a different view if they were Sigma Dot. Their viewpoint on this is not fact based so take it with a grain of salt. It comes down to the lens you personally get. Test it and then exchange it if it is a bad copy.

  4. Tests done with a single sample can be misleading. As an example, I read conflicting tests on the M43 Panasonic Leica 12 – 60 zoom. Some said is was soft in the edges and some said sharp edge to edge. On the lens, I had to keep returning the lens until the 5th one was sharp edge to edge. It is a gorgeous lens including bokeh when you get a good copy. My Leica m 18mm was sharp edge to edge but people kept saying they would get copies that were not centred and either the left or right side would be noticeable softer. I stupidly sold mine and eventually missed it. I purchased another one and it was quite soft on the right side so I got rid of it and instead purchased the absolutely amazing Panasonic S Pro 16-35 and no longer miss the 18mm.

    Hence, copy variation could be a testing factor so I need to see a number of competent reviews before I feel comfortable about a lens.

    • Red Dot Forum suggested that the Leica would be less prone to sample variation because of enhanced quality control but I’m not sure how that would work if both lenses were made in the same Sigma factory.

      • Ask Leica about their enhanced quality control on the m 18mm. I also purchased a m 50 1.4 that needed to be exchanged due to severe softness on one side. I also purchased a Leica m 240 that was so far off calibration of the rangefinder that it was rediculous. That after being on the wait list for a year….
        I think Leica less issues than most manufacturers but how some things get through their quality control baffles me. It could be that they have tighter tolerances on their parts so less issues but my experience shows some things are not being tested.

        • Sorry, I meant that you should ask Red Dot instead of Leica. All lenses, from all manufacturers have bad copies, good copies, and sensational copies. It is just like all products due to tolerances in the parts. My original 18mm was a sensational copy and I should never have sold it.
          I have a camera store that pretests my glass and I have a lot less problem.

          They told it is not uncommon to get a bad batch of glass at times….

  5. Has anyone compare these two with the Panasonic Lumix version, also f2.8? And twice the cost of the Sigma but less than the Leica?

    • I did hear from one photographer who says the Panasonic is inferior to both the Sigma and and fhe Leica. While I respect his views, I haven’t seen a formal test.

      • I saw a formal test that had me picking the Panasonic over the Sigma but both had some things better than the other. I do not recall what they are but I am not a 24-70 person. I will only buy a longer range zoom. I have owned both the Leica 24-90 and the Panasonic 24-105. I loved both: the 24-90 is sensational but heavy to carry all day. The 24-105 is far more than adequate for me and a joy to carry compared to the Leica.
        I do not know if I will buy another event zoom as I do not do events often anymore. I love carrying a fast fifty as gives me creative options and a nicer rendering than the zoom.

  6. I, too, watched the Red Dot expose. The images do in fact show a corner advantage to the Leica. Maybe the results are due to testing just one lens- luck of the draw? I would guess the weather sealing is better on the Leica- no switches. Then again, the switches are possibly magnetic, so there’s no opening into the barrel, anyway. Someone knows that. Perhaps apart from the Leica markup, economically there is the option to not use more marginal production elements?
    I have the 24-90- fabulous, heavy, and now 4 years on the lens does extend by itself while hanging off the strap. I wonder if current production 90’s do that?
    I think the manufacturer giveaway is that the zoom direction is opposite to other Leica zooms, and the same as Sigma zooms (in general). That tells me whoever did it, it’s not a truly Leica custom lens.
    That said, I think I’d do the Leica; just fear and superstition, I guess. And maybe weather sealing!

  7. I sense an interesting conundrum here – in one hand the Leica is slightly quicker, and perhaps a little optically better at the extremes. But in comparison the Sigma is a margin slower in AF, and more vague in the far extremes of the focal length.

    I look at this in two ways, if you are a hobbyist, with a tight budget and are not dependent on your results, then buy the Sigma, enjoy it, and keep the change. if your budget is no option, or you are a working pro who is paid on results, then the Leica is a no brainer.

    Thats my ten pence worth.

    • However, both these lenses are budget in comparison with, say, Leica’s 24-90, so the photographer probably wouldn’t choose them.

  8. I found the Red Dot Forum discussion very interesting. Two points in that discussion made me think I would choose the Leica version over the Sigma version. First, the metal construction of the Leica lens looks like it would enable the lens to put up with more punishment than the Sigma version. And second, the tests they did suggested that the Leica performed better than the Sigma on resolution, notably in the corners. This might be due to quality control being better for the Leica version. I would always be prepared to pay more for a lens if I thought that would ensure I didn’t buy a bad copy.

    Anyway I won’t be buying either, as I have the 24-90, a superb lens that beat both 24-70 lenses in Red Dot Forum’s tests!

    • RedDotForum are very very knowledgeable people but you have to remember that they in the first place are sales people as well. RedDotForum rated the Leica as an 8 and the Sigma as a 6.8. That in my opinion seems to go straight against the conclusions from PetaPixel: […the lenses have basically the same performance. Optically speaking, the images are nearly identical with only very subtle differences when shot at the lens’s respective focal and aperture extremes…]. In these words I do not sense a difference that is as significant as between 6.8 and 8. Hopefully more reviews will follow and hopefully they will more or less align in their conclusions.

      • I am also convinced that the test SL2 would bit have had profiles for the Sigma whereas the Leica would have done. This accounts for the comments about the Signa needing PP attention and doesn’t signify that the Signa is inferior in optical performance.

  9. I watched a discussion on Red Dot Forum which, as I recall, included a point that the Leica has one more glass element than the Sigma. On the principle of dating a body and marrying a lens I’d be inclined to buy the Leica lens new and match it to a used SL. I wonder how much difference in the real world the IBIS, improved autofocus improved video and or higher megapixel count of the SL2 or SL2-S would make in comparison to the SL. The EVF is broadly the same as is the size and weight of the body. That’s a bit of a side track but I’m looking at the lens as part of a package.

    • I don’t think there is any difference in internal elements. See my article last month where I list the spec comparison.

      • Ah OK. I recommend the Red Dot Forum video also although it can be hard work at about two hours long. I suppose my main train of thought is that the Leica lens as a stand alone purchase is hard to justify against the Sigma but as part of a package it is more appealing.

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