Sigma 50mm f/1.4 EX DG HSM (Nikon F)

Shoot this lens at f/1.4 and the background goes completely to mush, soft and edgeless behind a sharp-enough subject. That is the whole reason people bought the EX DG and the whole reason some people sold it. Released in 2008, it was Sigma's first 50mm f/1.4 autofocus lens, and it arrived as a premium alternative to the Nikon and Canon 50mm f/1.4s, costing more but pushing harder on subject separation and build. The big 77mm front element and the heavy barrel told you Sigma was throwing glass at the problem rather than chasing a price point.

Wide open it is soft in a specific way. Center sharpness is decent by f/1.4 but contrast drops, there is visible spherical aberration glow on highlights, and the corners are gone. Photographers either read that as dreamy or as broken. Stop down to f/2.8 and it cleans up fast; by f/4 it is genuinely sharp across most of the frame. The bokeh is the selling point: rounded, smooth, with the kind of falloff that lifts a head-and-shoulders portrait off a busy street. Color is slightly warm and saturation is moderate, less clinical than the later Art version that replaced it in 2014.

The honest weakness is focus. The HSM motor is quick but the lens is known for inconsistent autofocus calibration, front-focusing or back-focusing depending on the copy. On a Nikon F body shooting film you are likely manual-focusing anyway, which sidesteps the issue, but it is the reason this lens has a mixed reputation. There is also some longitudinal chromatic aberration wide open, about average for a fast fifty, green and magenta fringing on out-of-focus edges in high-contrast scenes. Flare resistance is mediocre against bright sources.

Who reaches for it: portrait shooters working on a budget, available-light people who want the f/1.4 dreaminess for environmental work, and film photographers who like the older Sigma rendering signature over the surgical Art look. It is a documentary and street lens in the hands of someone who wants atmosphere more than resolution charts. On a film SLR it pairs naturally with fast black-and-white stock pushed in low light, where the soft-glow wide-open character does its best work.

Metering wide open is where you actually use this thing, so feed Zone Light Meter your real shooting aperture of f/1.4 rather than rounding to f/2. At that speed the difference between an indoor reading at f/1.4 and f/2 is a full stop, which is the gap between a usable frame and an underexposed one when you are working by window light at dusk. The 77mm filter thread is generous, easy to find ND and polarizers for, though it makes the lens front-heavy.

Today the EX DG sells cheap on the used market, often half what the Art version commands, and that is its argument. People cross-shop it against the original camera-brand 50mm f/1.4 lenses and the Sigma Art. If you want clinical sharpness, buy the Art. If you want a fast fifty that turns backgrounds to soft wash and you do not mind babysitting focus, this is a lot of glass for the money.