Live view lets you take photos without using the viewfinder which makes you less obstrusive and this works very well during street photography where you don't want to get people's attention. Face-Detection Focusing
Face detection focusing mode is very helpful in the street scenes where you focus on a face, since you can concentrate on framing and other adjustments while the camera handles the focus for you. Large Full frame (35.9 x 23.9 mm) sensor
Large sensor in Sigma fp ensures a good low light image quality compared to smaller sensor, and it also provide shallow depth of field and a nice blurry background when needed.
Medium sized Body
Mirrorlessbody of Sigma fp is a good combination of relatively small size and good handling camera, without giving the impression of a professional camera.
No Built-in Viewfinder
In the lack of a a viewfinder, holding the camera away from the body while using live view is not very stable, especially with heavy camera bodies and lenses. Besides, LCD screens are very hard to read under bright sunlight. No Image Stabilization
An articulated screen gives you the flexibility to shoot in non traditional positions such as waist level, which helps you to be more creative and unobtrusive in the streets.