Sony FE 135mm F/1.8 GM SEL135F18GM

The Sony FE 135mm F/1.8 GM is a full frame prime for Sony E mount cameras, released in 2019. It aims at portrait, wedding and indoor event work, where a long, fast prime for single subjects makes sense.

The 135mm focal length suits portraits and candid frames from farther back. Exact framing depends on subject size and distance. Perspective follows where you stand, so check the face and its relationship to the background as you choose a position. A room needs enough space for the composition you want.

The main trade-off is flexibility. The focal length is fixed, so you frame with your feet instead of zooming. The reward is a bright f/1.8 opening. For many portrait shooters, that trade is worth making.

At 2 lb 1.5 oz (950 g), this is a heavy prime. The barrel runs about 5 in (127 mm) long and 3.52 in (89.5 mm) wide. A screw-in filter must match the 82mm front thread, and a polariser of that size can reduce glare in outdoor portrait light.

The f/1.8 maximum aperture defines this lens. It gives more room for a faster shutter speed or lower ISO than a smaller opening. This helps in reception rooms and theatres. A nearby subject can also have a soft background when there is enough space behind it.

Depth of field depends on aperture and focus distance. It can be shallow for close portraits at f/1.8, so precise focus on the eyes matters. Stop down when more of the face or several people at different distances must stay sharp. Review focus before the subject changes position.

Closest focus is 2.3 ft (70 cm), measured from the sensor. This is the minimum separation for nearby subjects. It does not establish a comfortable distance for a person. Choose a position that gives the subject space and use that distance to judge the framing.

The fixed focal length gives no zoom adjustment. Indoors, you may need room to step back for a wider portrait or group. Think about the space available before choosing this lens for an event. The optics specification score is 88 out of 100.

There is no stabilisation in the lens. Small camera movements are visible in a telephoto view. A camera with body stabilisation can help with shake, while firm support helps with slower exposures. Moving people still need enough shutter speed for their movement.

The barrel is sealed against dust and moisture. That suits outdoor portrait sessions and wedding days when the weather turns. A fluorine coating on the front element helps dust and fingerprints release during cleaning, useful for a lens handled often on location.

The optical design uses 13 elements in 10 groups, including low-dispersion and super-low-dispersion glass. Such glass helps reduce chromatic aberration, the coloured fringes that can appear along high-contrast edges such as a backlit hairline. Aspherical surfaces also help correct distortion, a fault that curves straight edges.