ISO Versus EV Compensation

[ericgraig]

My new (to me) X-T1 will be arriving this afternoon and afer reading and aborbing Rico Pfirstinger's book on the camera I started to wonder what exactly is the difference between changing the ISO for a picture versus changing the EV compensation. The senor doesn't get anymore sensitive to light when you change the ISO. It's not like switching out a film back loaded with FP4 and loading one instead with  HP5. The camera simply amplifies the energy the sensor captures when you move from its native ISO (200 according to Pfirstinger) to something higher. I get that. But then what does the EV compensation dial do?

 

Suppose you're in manual mode and you need to use a specific shutter speed and aperture combination but at the same time you need another stop of exposure. Does it make any difference whether you move the ISO dial from 200 to 400 or instead add one stop of exposure via the EV dial.

 

I just don't get it.

 

Eric

 

eric-graig.squarespace.com

[d750guy]

The exposure compensation dial does nothing in manual mode except change the metering.   Your exposure is set by you with ISO/aperture/shutter speed and that's it.

 

In program, aperture priority and shutter priority modes, when the camera chooses exposure, exposure compensation is used when the camera underexposes or overexposes an image in difficult lighting situations. 

[ericgraig]

Makes sense, I guess if you use one the automatic modes.

 

Thanks