viewfinder
 US /ˈvjuːˌfaɪn.dɚ/
 UK /ˈvjuːˌfaɪn.dɚ/

1. 
visor
a device on a camera showing the field of view of the lens, used in framing and focusing the picture.
:
• 
She looked through the viewfinder to compose her shot.
Ella miró a través del visor para componer su toma.
• 
The old camera had a bright, clear viewfinder.
La cámara antigua tenía un visor brillante y claro.