Sony introduced the FE 28–70mm f/2.0 G Master (SEL2870GM) on November 19, 2024 – its first full-frame E-mount zoom with a constant f/2.0 aperture. Sony’s press release notes that this is the “first… Sony zoom lens with a constant F2 aperture and 77th lens in the Sony E-Mount lineup”. Despite the unusually fast aperture, the lens remains surprisingly compact for what it is – Sony quotes dimensions of 92.9×139.8 mm and weight ≈918 g (32.3 oz). It carries an 86 mm filter thread and an 11‑blade circular diaphragm, and is sold at a premium price (≈$2,898 USD at launch). (In practice it became available in December 2024.) In short, this lens is officially a Sony G Master zoom with specs that include 28–70 mm range, constant f/2.0–22 aperture, 0.38 m minimum focus, 11 rounded blades, and dust/moisture-resistant construction.
Unusual Brightness for a Zoom
The defining feature of the SEL2870GM is the constant f/2.0 aperture – a full stop faster than the ubiquitous f/2.8 standard zooms. In practical terms, that one-stop advantage means the lens gathers about twice as much light as an f/2.8 zoom at the same ISO and shutter speed. Reviewers note that this lets photographers shoot in darker conditions without raising ISO or slowing shutter speeds. For example, CineD observes that with f/2 “there isn’t as much of a need to boost ISO or slow the shutter, resulting in less noise and blur”. In other words, you can use roughly one stop lower ISO (or one stop faster shutter) and still get the same exposure as a typical f/2.8 zoom – helpful for low-light and fast action. The bright aperture also produces much shallower depth-of-field, yielding very pronounced background blur (“bokeh”) even at 28 mm. Sony emphasizes that the 28–70mm f/2.0 delivers “prime-like” bokeh and “extraordinary” shallow-DOF effects. Petapixel’s reviewer summed it up by calling the lens “like a pocket full of f/2 primes in one”.
Contrast this to most standard zooms (e.g. Sony’s own FE 24–70mm f/2.8 GM II): those are smaller, lighter, and cheaper, but require higher ISO or slower shutter in dim light. The SEL2870GM deliberately trades the extra bulk and cost for that one-stop speed. (For scale, the 24–70 mm f/2.8 GM II weighs 695 g, vs 918 g here; and uses an 82 mm filter instead of 86 mm.) In practice, the new lens is most directly comparable to the Canon RF 28–70mm f/2.0 L, which it effectively undercuts in size and price. As one review notes, Sony “managed to reduce the weight and have better corner sharpness” relative to that Canon counterpart.
Advanced Optical Design and Construction
Packing f/2.0 into a zoom required a high-end optical layout. Sony used 20 elements in 14 groups in the FE 28–70mm f/2 GM. Notably, it includes three “XA” (extreme aspherical) elements and three aspherical elements to flatten the field and minimize aberrations. Sony’s press materials emphasize these large, precision elements: they enable “extremely sharp corner-to-corner results” even at f/2. To combat chromatic aberration, the lens also has three “Super ED” and one ED (extra-low dispersion) glass elements. The overall effect is very high resolving power: in tests with a 61 MP camera, reviewers found very consistent sharpness from center to edges even wide-open. Like other GM lenses, this one uses a floating focus group (a secondary focusing element) to keep image quality high at close distances – allowing the min focus distance of 0.38 m across the zoom range.
Sony also applied its latest lens coatings. A new Nano AR Coating II is used on the elements to suppress flare and ghosting. Reviewers report that flare control is excellent: even with strong light at f/2, there are “no distracting ghosts or washed-out areas” and stopping down doesn’t introduce flare issues. Lensbreathing (the change in angle-of-view while focusing) is also minimized compared to typical zooms. Petapixel notes there is some field shift at 28mm (common for fast wide lenses), but it’s modest and can be corrected via Sony’s in-camera breathing compensation; at longer focal lengths breathing is “very well controlled”.
Mechanically, the lens is built to professional standards. It has a robust metal/plastic hybrid barrel with a fluorine coating on the front element to repel dust and moisture. All controls (buttons, switches, mount ring) use silicone gaskets for weather resistance (Sony calls it dust- and moisture-resistant, though not 100% waterproof). The focus ring uses Sony’s Linear Response design for precise manual focus. There is a zoom ring with an adjustable “smooth/tight” torque switch (rare on Sony zooms), and an aperture ring with a click ON/OFF switch and lock. Additional programmable focus-hold buttons and an AF/MF switch give video users more control. Finally, Sony opted for a very short zoom throw: the barrel only extends about 0.68–0.7 inches from 28→70 mm. This “short-throw” design means zooming doesn’t significantly unbalance a gimbal or tripod setup, an important feature for video professionals.
Autofocus and Video Performance
The SEL2870GM uses four XD (extreme dynamic) linear motors to drive autofocus. In practice this yields very fast and accurate AF despite the large glass elements – reviewers report it can track high-speed action easily. Lensrentals notes that even on bodies shooting 120 fps burst (like the α9 III), the autofocus can keep up. The lens maintains AF even while zooming, and there’s very little motor noise or aperture noise (thanks to a newly developed silent aperture unit) – making it well-suited for video. Sony highlights its video-focused features: minimal focus breathing, support for “breathing compensation” on cameras, and full compatibility with 4K 120p and FHD 240p recording without focus failures. In short, this zoom is engineered to serve as a pro cine lens as much as a stills lens.
Image Quality and Bokeh
Pixel-peeping: Tests show that the 28–70 F2 GM is extremely sharp. Dustin Abbott’s lab charts (61 MP camera) showed razor-sharp detail from center to corner at f/2. Corner softness is minimal wide-open; stopping down to f/2.8–f/4 yields only slight improvements in corner contrast. This performance is “in line with prime lens quality,” per Sony’s claim. Chromatic aberration (both axial and lateral) is also very well controlled thanks to the ED glass – reviewers found almost no visible color fringing in real-world images.
Bokeh: A large part of this lens’s appeal is its out-of-focus rendering. Official Sony sample images demonstrate this dramatically. For example, one in-house portrait taken at 70 mm and f/2 (below) keeps the subject’s face tack-sharp while backgrounds blur into creamy smoothness. Specular highlights turn into soft discs, even slightly elliptical (“cat’s eye”) at the edges. As one tester observes, “everything stays nice and round when the aperture is stopped down,” and backgrounds “blur into a palette of silky tones”. Another Sony sample (50 mm, f/2) of a small figurine shows the foreground figure in crisp focus with a busy background rendered into pleasing bokeh. Petapixel praises the bokeh as “delightful,” noting no onion-ring artifacts and very smooth focus transitions.
Sony’s own sample portrait (70 mm, f/2) showcases the SEL2870GM’s rendering: the subject’s face is pin-sharp against a very gentle, creamy blur. Reviewers attribute this to the 11-blade circular aperture and careful aberration control. Even at close focus, the lens performs well: it achieves about 0.23× magnification at 70 mm (roughly 1:4 life-size), and images remain sharp even at the minimum distance.
Close-up shots from Sony’s gallery (here at 50 mm, f/2) further illustrate the shallow depth-of-field. The ballerina figure is sharply rendered, while the foreground lamp and the background objects blur into smooth, rounded highlights. As Sony notes, the bright f/2 aperture produces “extraordinary bokeh” and the three XA elements ensure sharpness even wide open. In short, image quality – especially in the in-focus region – is stellar for a zoom. Reviewers uniformly remark on the prime-like look of the 28–70 F2 GM, both in sharpness and in how it renders out-of-focus areas.
Comparison to f/2.8 Alternatives
Several other popular full-frame zooms occupy roughly the same focal range, but all have f/2.8 maximum aperture (or slower). Key points of comparison include:
- Sony FE 24–70mm f/2.8 GM II: Sony’s own standard zoom (released 2022) is smaller (87.8×119.9 mm) and lighter (695 g). It has an f/2.8–22 range and 11‑blade diaphragm like the f/2.0 lens, but the narrower aperture means about one stop less light and less background blur. The GM II’s resolution is also excellent (it too is nearly corner-sharp), but the 28–70 f/2.0 can deliver images equally sharp at f/2.8 with even shallower depth of field. The f/2.8 lens uses an 82 mm filter and costs roughly $2,200; by contrast, the f/2.0 GM uses 86 mm filters and costs roughly $2,900 at launch. Put simply: the FE 28–70 F2 GM trades extra bulk and higher price for one stop of speed. (The FE 24–70 f/2.8 GM II still has one advantage: it reaches a true 24 mm wide angle, which the 28–70 F2 does not.)
- Tamron 28–75mm f/2.8 Di III G2: A third-party zoom with a similar range, the Tamron 28–75 mm f/2.8 G2 is much more compact (75.8 × 117.6 mm) and light (540 g). Its single advantage is affordability (around $899), and it uses a 67 mm filter. Optically, the Tamron is very good – quite sharp and with reasonably smooth bokeh – but it still can’t match the Sony GM lenses in resolving power and corner-to-corner consistency. The Tamron also lacks the extra-custom controls (aperture ring click switch, focus buttons, zoom torque adjust) and weather sealing of the Sony. In short, Tamron’s 28–75 mm is a great value, but it gives up two-thirds of a stop of light (f/2.8 vs f/2.0) and some build and autofocus refinements.
- Other f/2.8 standards: (For completeness, lenses like the Sony FE 24–105 mm f/4 G OSS or cheaper kit zooms can’t match the f/2 fast aperture.)
Trade-offs and Considerations
The FE 28–70 mm f/2.0 GM is a remarkable lens, but users should be aware of its compromises:
- Size & Weight: At 918 g and nearly 14 cm long, it’s large (and uses 86 mm filters). This makes it heavier and more expensive to accessorize (e.g. 86 mm NDs/polars are costly) than 24–70 f/2.8 zooms. It’s about 28–30% heavier and larger than Sony’s 24–70 f/2.8 GM II.
- Price: The ~$2,900 launch price is “a big ask” even by professional standards. You’re essentially paying for a set of fast primes in one lens.
- Limited Wide-end: The range starts at 28 mm. Photographers who need true 24 mm fields (wider perspective) will find this lens doesn’t go as wide as the classic 24–70 zoom. Sony presumably chose 28 mm to keep the optics manageable (Dustin Abbott points out that going wider to 24 mm at f/2 would make the lens even larger and more complex).
- Vignetting: Wide-open, there is some corner shading. However, tests show it is actually quite low for such a fast lens – roughly +0.5 stop of light falloff at 28 mm (correctable with +15 bias in Raw). Vignetting drops off as you stop down (e.g. only about –0.6 stop at f/4).
- Distortion: At 28 mm there is moderate barrel distortion (
–3% uncorrected), and at 70 mm slight pincushion (+1–2%). In-camera or in-software corrections can handle this easily, but it’s a level to be aware of (more pronounced than some slower zooms). - Soft Corners at f/2: The corners are not quite as sharp wide-open as the center. Reviewers note a “touch of softness” in the extreme corners at f/2. Stopping down to f/2.8 or f/4 improves corner contrast.
- Focus Breathing: As mentioned, focusing at 28 mm does pull in the framing slightly. Video shooters should note this (though it can be compensated). The breathing is better controlled than many zooms, but it is not zero.
- Weather Resistance: The lens is dust- and moisture-resistant (gaskets on controls, fluorine coating, etc.). However, Lensrentals notes it is not fully weather-sealed like some pro telephotos.
- No Built-in IS: Like most Sony GM lenses, this one relies on in-body stabilization. It has no optical OSS of its own.
- Cost of Accessories: The large front element (86 mm) means polarizers and NDs cost more and are physically heavier.
In sum, the trade-offs boil down to size/weight, price, and the narrower zoom range (28–70 mm vs 24–70 mm). If those are acceptable for your shooting, you gain the one-stop aperture. As one reviewer puts it, this lens “may not be for everyone” (especially if you want 24 mm or prefer f/2.8 size) – but for its intended user (portrait/event/video pros who want maximum speed), it fills a unique niche.
Conclusion
The Sony FE 28–70 mm f/2.0 G Master (SEL2870GM) is an unprecedented lens in the full-frame E-mount lineup. It is officially a Sony G Master zoom lens (released late 2024) with constant f/2.0 aperture. Its optical formula (20 elements with three XA asphericals, ED glass, Nano AR II coating, etc.) and four XD motors deliver image quality and AF performance on par with primes. The result is outstanding corner-to-corner sharpness even at f/2. Where most standard zooms cap out at f/2.8, this lens stands out by letting in that extra stop of light, translating into better low-light capability and shallower depth of field.
However, this advancement comes at a cost: the lens is significantly larger, heavier, and more expensive than typical zooms. Its main alternatives (the f/2.8 GM zoom and Tamron’s 28–75 mm) are smaller and cheaper but slower. Users must weigh the one-stop advantage against the bulk and price. Many reviewers conclude that for the right application – especially event, wedding, portrait, or run-and-gun video work – the SEL2870GM is a game-changing tool. As Sony’s engineers put it, it was built to be “a high-performing zoom lens that could be a strong single lens alternative to multiple primes”. For enthusiasts and professionals who need that f/2 speed and premium optics in a zoom form, the Sony 28–70 mm f/2.0 GM is truly unique.
Sources: Official Sony announcements and specs; hands-on and review reports from PhotoRumors/CineD, B&H, Lensrentals, Dustin Abbott, PetaPixel, and others. All data and quotes are from reliable photography sources and Sony’s own materials.