Sigma 85mm f/1.2 DG Art vs Sony FE 85mm f/1.4 GM II: Portrait Blind Test on the Sony A7 IV with Lily

Lily (@lilly.kirova) and I did a side-by-side test of two fast 85mm portrait lenses for Sony full frame: the Sigma 85mm f/1.2 DG Art and the Sony FE 85mm f/1.4 GM II. Lily wore a camel double-breasted blazer over a black satin shirt, with a grey mini skirt, lace tights and a small black bag, which looked great against the fall colors.

This time there is only one variable: the lens. Every photo was shot on the same Sony A7 IV in Standard creative style at ISO 100. For each pose I shot one lens, swapped to the other and shot again from the same spot. Both lenses are wide open in every pair: f/1.2 on the Sigma, f/1.4 on the Sony. The photos are the original, unedited camera JPEGs, and white balance matched on both lenses in 35 of the 38 pairs (5700K or 5900K).

Gear:

• Sony A7 IV
• Sigma 85mm f/1.2 DG Art
• Sony FE 85mm f/1.4 GM II

The full video is a blind test with all 38 pairs: each pair is shown without names during a 10-second countdown, then the lens and settings are revealed. Below are 14 sample pairs, a mix of half body and full length shots. Play along: guess which side is the Sigma and which is the Sony, then tap Reveal cameras.

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Autumn Canopy

We started under a big canopy of turning trees, with leaves all over the path. The busy branches and leaves in the background are a good test of how each lens renders out-of-focus detail.

Backlit Canopy

Turning her around put the sun behind her, so light came through the leaves and wrapped around her hair. Backlight like this shows off contrast, flare control and how smoothly each lens blurs the bright background.

Blue Pole Road

Next was a quiet road lined with fall trees, with orange and yellow leaves on the ground and lots of color in the background.

Ginkgo Path

The ginkgo trees were bright yellow, which made for a glowing background along the path.

Hallway

In a long covered hallway, the rows of ceiling lights turn into soft shapes behind her, and the warm brown walls match the blazer. With five poses this was our biggest set, so it gets three pairs here.

Concrete Bench

A seated pose on a concrete bench beside a lawn.

Plaza

We finished in a concrete plaza, with clean modern architecture behind her.

Want to see all 38 pairs? The full blind test on YouTube goes through every pair with a countdown before each reveal. Keep score and let me know how many you got right in the comments.

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Side by Side: What I Noticed

I measured brightness and color on her face in the original JPEGs of all 38 pairs (same camera, same Standard style, both lenses wide open):

• Exposure: I shot in manual at ISO 100, and the Sigma shots ended up with a faster shutter speed in 34 of the 38 pairs, about half a stop faster on average. That's close to the 0.44 stop of extra light that f/1.2 lets in compared to f/1.4. With that, her face came out equally bright on both lenses (within a few hundredths of a stop on average).
• Color: in the 35 pairs where white balance matched, the Sigma came out warmer in 32 and slightly more saturated in 26. The Sony GM II renders skin and the blazer a little cooler and more neutral, so the Sigma's warmth is a lens difference, not a camera setting.
• Framing: both are 85mm lenses and I shot from the same spot, so her face is about the same size in both frames. On average it was only 2 to 3 percent smaller in the Sigma shots.
• Bokeh: at f/1.2 the Sigma's aperture is about 71mm wide, versus about 61mm for the Sony at f/1.4. That makes out-of-focus highlights about 17% larger and the depth of field a little under half a stop shallower at the same distance. It's a real difference, but a small one, which is what makes a blind test like this tricky.

Which one do you like more? Let me know in the comments on the YouTube video above, and tell me how many of the blind test pairs you guessed right.

Shop the Gear

• Sony A7 IV (B&H)
• Sigma 85mm f/1.2 DG Art
• Sony FE 85mm f/1.4 GM II (B&H)