Sirui Enters the $149 Autofocus Prime Market With Swift 20mm and 40mm

Sirui has priced its first autofocus prime lenses at $149 each, entering the crowded budget-autofocus segment against Viltrox's comparable Air-series glass. The new Swift lineup launches with two full-frame focal lengths, a 20mm F2.4 and a 40mm F2.2, and both are available to pre-order now in Sony E, Fujifilm X and Leica L mounts.

The move matters for working photographers because it extends the sub-$150 autofocus prime category — until recently dominated by Viltrox's 20mm F2.8 and 40mm F2.5 Air lenses — to a second manufacturer. For shooters who build lightweight travel or documentary kits, that means more choice at a price point roughly one-fifth of a typical first-party fast prime.

What do the Swift lenses add over Viltrox's Air series?

Unlike the similarly affordable Viltrox 20mm F2.8 and 40mm F2.5 Air, both Swift primes include on-lens controls that many working photographers expect:

• a clicked aperture ring
• a manual focus ring
• a customizable Fn button
• an AF/MF switch on the barrel

That control set is unusual at this price. It allows aperture changes and focus-mode switching without entering camera menus, which matters during fast-moving client work such as events or run-and-gun video.

What are the optical specifications?

Each lens uses a stepper motor (a motor type that moves the focus group in fixed increments, favoring quiet, quick autofocus for video) and Sirui promises minimal focus breathing (the slight change in framing that occurs while focusing). Both carry nine-bladed diaphragms, accept 58mm filters, and carry Sirui's claim of weather resistance against dust and splashes — a manufacturer claim that buyers should weigh against the modest price until independently tested.

The 20mm F2.4 uses an 11-element, 9-group design containing 2 aspherical, 2 ED (extra-low dispersion, reducing chromatic aberration) and 2 HRI (high refractive index) elements. Minimum focus distance is 0.2m (0.65 feet). Sirui does not publish weight or dimensions for the X-mount version, but the L-mount model weighs 212g (7.5oz) at 60.3mm (2.4 inches) long, and the E-mount version 207g (7.3oz) at 62.3mm (2.5 inches).

The 40mm F2.2 uses a slightly different formula: 11 elements in 8 groups, with one aspherical and two ED elements. Its minimum focus distance is 0.4m (1.3 feet). Sizes mirror the wide model. The E-mount version weighs 210g (7.4oz) and measures 62.3mm (2.5 inches); the L-mount version weighs 215g (7.6oz) and measures 60mm (2.36 inches).

Should budget-conscious buyers pre-order?

At $149 each, both lenses position Sirui directly against Viltrox in a segment where optical compromises — slower F2.2–F2.4 maximum apertures and unverified durability claims — trade against aggressive pricing and full external controls. Independent testing will determine whether the Swift primes match the optical performance their specification sheets imply; until then, the pre-order window is open at Sirui's store, and the arrival of a second player suggests further price pressure on budget autofocus primes through 2026.