Aperature and Shutter Speed

AV is Aperture - The points of light intersect the sensor as a cross section of a cone.

Size of the sensor matters.

Effective use of shutter speed can provide fantastic images.

To achieve DOF.. 

• Use shorter focal lengths e.1.18mm.
• Use a tripod. Where is is possible to set slower shutter speeds over longer times. 
• Use "faster" filmes/ The ISO increases the depth of field by one stop while iso 400 increases it by two. 

Less DOF... 

Using a smaller lense, Moving from 100 to fo ISO. 

Digital ISO.

Digital ISO speed settings are meant to be used in the same faship as film ISO settings after which they are named...

Digital cameras have adjustable ISO values, allowing to vary the light sensitivity as you go. 

Noise

The ISO depends on the size of the sensor. 

Photoshop has the ability to reduce noise, but best to snap the photo right.

Fast ISO allows for fast shutter speeds in low light conditions. 

....night, concert, fashion show, overcast...

Bigger sensors have beter signal-to noise ratio.