Pphotonstophotos.net measured the Sigma FP-L dynamic range and as you can see it clearly outperforms the Sony A7rIV. That’s a big surprise!
Dpreview published the full Sigma 35mm F1.4 DG DN Art field review and concluded:
Both E-mount and L-mount versions of the Sigma 35mm F1.4 are very sharp lenses, and in most respects can deliver great image quality even when shooting wide-open. Although there are issues with ghosting and cat’s eye, in many situations you’ll be able to work around these.
And while it’s perhaps a tad front-heavy on smaller bodies, handling is otherwise excellent. We’re fans of the lockable aperture ring, silky-smooth focus ring and rubberized, lockable lens hood in particular.
If you’re an L-mount shooter, the Sigma 35mm F1.4 represents a very nice option for achieving a shallow depth-of-field and overall good image quality while staying on a reasonable budget. The Sigma 35mm F1.2 DG DN is also worthy of consideration, but you’ll have to spend a lot more and work out your biceps for the benefits it can bring.