In this comparison I want to show you the difference between a camera with a small 1/2 inch sensor such as the Sony EX1 and a large sensor camera such as the Sony FS100 or your typical DSLR which has what is called (in general) an APS-C sized sensor, which is close to the depth of field (in-focus range) look of a 35mm film camera you see in movies.
The idea of this comparison test was to show the depth of field with same shot on both cameras with a similar aperture of f1.8 on the FS100 and f1.9 on the Sony EX1. The lens I used on the FS100 was a 50mm.
Sony FS100 setup infront of the subject
Sony FS100, 50mm lens at f1.8
Above you can see how easy it is on the large sensor camera to drop the background out of focus with a 50mm lens at that distance at f1.8
Below is the same shot with a traditional small sensor camera
Sony EX1 matching distance and shot with the original FS100 setup
Sony EX1 shot at f1.9
As you can see the difference is quite dramatic, however this doesn’t mean you can’t put the background out of focus on a small sensor camera.
In order to put the background really out of focus on a small sensor camera you must zoom in, the further you zoom in the more the background is compressed (gets larger) and blur.
Another way is if your camera has a macro (close focus) ability, in which case you get up as close as you can to the subject and focus, the background will look small and distant but you will be able to drop the background out of focus this way also.
Sony EX1 zoomed in to a tight shot in order to put the background out of focus still at f1.9
To have a deep depth of field (in-focus range) on a large sensor camera, simply close down the aperture on the lens.
Sony FS100 50mm lens at f11
If you would like more detail or have questions about this comparison, let me know in the comments.