Sigma 50mm f/1.4 EX DG HSM lens for Sony A-Mount [77]

Sigma's proven 50mm f/1.4 prime for Sony A-Mount shooters.

The Sigma 50mm f/1.4 EX DG HSM is a full-frame prime with a well-established reputation built on its wide f/1.4 maximum aperture and 9 rounded diaphragm blades. Those blades matter: they produce smooth out-of-focus rendering that a straight-bladed aperture simply cannot match at the same price point. The single aspherical element in the 8-element, 6-group optical formula keeps spherical aberration in check at wide apertures, where lesser 50mm lenses tend to fall apart.

The HSM ring-type ultrasonic motor drives autofocus quietly and quickly, and full-time manual focus override means you can fine-tune focus without switching modes. The non-rotating 77mm filter thread holds polarizers and graduated NDs in place during focus pulls. Internal focus keeps the barrel at a fixed 68mm length, so the lens balances consistently on the camera. At 505g with a metal mount and plastic barrel, the EX build designation reflects Sigma's tighter tolerances for this line. The minimum focus distance of 0.45m gives you enough working room for environmental portraits without straining.

Who It's For

Portrait photographers working with Sony A-Mount bodies get direct access to f/1.4 separation with the kind of out-of-focus quality that 9 rounded blades support. Street and documentary shooters benefit from the HSM motor's quiet operation and the fast aperture's low-light capability in available-light situations. Sony A-Mount APS-C users who want a prime for everyday focal lengths will find the DG optical formula delivers full-frame-quality corrections even on crop sensors. Event photographers who rely on consistent manual focus override during fast-moving coverage will appreciate the full-time manual focus capability without mode switching.

Key Features

• 50mm f/1.4 prime with nine rounded diaphragm blades
• Single aspherical element reduces spherical aberration at wide apertures
• HSM ring-type ultrasonic autofocus with full-time manual override
• Internal focus maintains fixed 68mm barrel length
• 77mm non-rotating filter thread for stable polarizer use
• Metal mount with 505g weight and 0.45m minimum focus distance

FAQ

What autofocus motor does the Sigma 50mm f/1.4 EX DG HSM use?

A ring-type ultrasonic (HSM) motor that drives focus quietly and quickly, with full-time manual focus override so you can fine-tune focus without switching modes.

How many diaphragm blades does this lens have, and why does it matter?

Nine rounded blades. Straight blades produce harder bokeh transitions; rounded blades render out-of-focus areas more smoothly at the same price point.

Does the filter thread rotate during focus?

No. The 77mm filter thread stays fixed during focusing, so polarizers and graduated NDs stay in place during focus pulls.

What happens to the barrel length when you focus?

Nothing. Internal focus keeps the barrel at a fixed 68mm length, so the lens balances consistently on the camera without extension or contraction.

Can you use this lens on Sony APS-C cameras?

Yes. The DG designation means it's optimized for full-frame 35mm sensors but works on APS-C bodies with Sony/Minolta A-Mount.

What's the closest you can focus with this lens?

0.45 meters (17.72 inches), with 0.14× maximum magnification. That's enough working room for environmental portraits without straining.

How is the EX build different from Sigma's standard line?

EX reflects tighter tolerances and a metal mount paired with a plastic barrel and hood, giving you better mechanical consistency at this price tier.