Sigma 35 1.4 vs. Nikon 28 1.8G - DOF and perspective

I'm still working on the review of the Sigma 35 1.4 (previewed here).  Meanwhile, I wanted to show the differences (and similarities) between the Sigma 35 1.4 and the Nikon 28 1.8G (reviewed here) in terms of their depth of field wide open and their perspective and field of view.

Testing protocol: I put a subject in front of a wall and without moving the subject, I took shots with the 28 and the 35 wide open, at various distances, keeping the subject size in the frame approximately equal (requiring me to move a little closer to the subject when shooting with the 28mm).

Close-up headshot:

35 1.4

28 1.8

Both of them have a shallow depth of field, although the 35 is significantly more shallow.  In terms of perspective, the subject's face with the 28mm at this distance looks a little narrow.  The subject's face with the 35mm at this distance looks like it has normal proportions.

Headshot

35 @ f/1.4

28 @ 1.8

Once more the 35 at f/1.4 looks like it has much shallower DOF compared to the 28 at f/1.8 at this distance.  In both shots, the subject's face looks more proportional compared to the previous set, though the 35 still looks more normal.

Bust

35 @ f/1.4

28 @ f/1.8

At this distance, the difference in DOF looks less apparent and the subject's proportions look about the same.

Upper body:

There is very little difference in the DOF of the shots, and both have normal proportions.

In the following pair of shots, the composition is different, but the size of the subject is about the same:

There is even less of a difference in DOF and the subject's proportions.

Full length:

35 @ f/1.4

28 @ f/1.8

Almost identical in DOF and proportions.

I hope this comparison helps you choose between these two primes.