>>4136750Learn to art
Shading is a major part of illustrating depth. I will say this for the final time, a two dimensional image has no real depth. A lens, AKA a single eye, can not capture an image in 3d. You can only trick the brain into seeing in that way.
With one single eye, you rely entirely on shadows, perspective, and focus to estimate depth, like biological CDAF. With two eyes, you can perceive depth by comparing the differences between two images like a biological rangefinder.
The sigma image looks flat and confusing because the shadows on the flower tufts are pulled up and all bloomy because sugma's coatings are shite, and the wrong things are all in focus at the wrong places which doesn't look natural enough for the human eye/brain complex to think it's actually looking at the object. There's only perspective left, and it's not dramatic, so it's harder to estimate depth in the ligma photo.
In other words, sigma lenses are dogshit. Fuck your lenstip MTF charts.The pictures look like trash. Save your money. A $100 plastic nikkor from the 90s takes better photos.