You've probably noticed it in wedding photos — the subject is sharp and the background melts into soft circles of light. That effect is called bokeh and it's created by shooting at a wide aperture on a prime lens.
I shoot almost every wedding on a 50mm and 85mm prime lens at f/2.2 to f/2.5. Here's why.
At f/2.2 the depth of field is extremely shallow. Only a thin plane of the image is in sharp focus. Everything in front of and behind that plane blurs smoothly. On a person's face that means the eyes are sharp while the ears and nose fall slightly soft. On a full length portrait it means the couple is sharp while the venue behind them becomes abstract color.
This is not a style choice for everyone. Some photographers prefer everything sharp. Some couples want to see every detail of their venue in every photo.
My clients tend to be people who want to feel something when they look at their wedding photos. The soft backgrounds remove distraction. The subject — you — becomes the entire image.
The 85mm specifically is a portrait lens. At f/2.2 on an 85mm the background compression is significant. Venue lights become large soft circles. Garden greenery becomes impressionistic. The effect is most visible in photos from the reception when there are lights everywhere.
The tradeoff is that shooting wide open requires precise focus. At f/2.2 there is very little margin for error. That's why I shoot so many frames and why I've spent 150 weddings learning exactly where to focus and when.
If you've seen my portfolio and you like what you see — that's the lens, the aperture, and ten years of practice.