[stoppingdown]

An insane number of elements seem to be the trend. I don't like it really. Less so because of the weight but because of the required centering accuracy.

And also flare...

https://www.lenstip.com/159.3-article-Si...rties.html

When it comes to the performance against bright light, we feel the bar couldn't have been raised higher - in the case of the new Sigma you get as many as 27 elements positioned in 19 groups and it means as many as 38 air-to-glass surfaces where you can catch unwanted reflections. What's more, you also deal with a big front element that is not hidden inside the barrel very deep. The high zoom factor, autofocus, and image stabilization units mean it's rather cramped inside the casing; you don't get many places where apertures or ribs, helping to fight off reflections, can be installed.

It would be difficult to expect excellent performance so we are not especially surprised that we managed to catch quite a lot of light artifacts. As a kind of consolation you might add that these are present only when the sun is situated close to the frame corner and these aren't frequent situations while taking photos with this kind of equipment.