Both Canon 170 IS and Canon ELPH 180 have 20.0 MP resolution sensors but Canon 170 IS's sensor is 1/2.3' (6.17 x 4.55 mm ) and Canon ELPH 180's sensor is 1/2.3 (6.17 x 4.55 mm ).
Since Canon ELPH 180's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Canon 170 IS.
Below you can see the 170 IS and ELPH 180 sensor size comparison.
Sensor Size and Resolution Comparison image of Canon 170 IS and Canon ELPH 180 Cameras
Canon 170 IS and Canon ELPH 180 have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture.
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Canon 170 IS
or the
Canon ELPH 180 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(1/2.3' versus 1/2.3),
so compare them at the same framing rather than the same focal length.
Put the same focal length on the smaller sensor and it will show less depth of
field, not more, because it also crops tighter. The calculator shows the
full frame equivalent focal length for each body so you can match the framing.
