3 clicks of ss (in one direction) from any SS value is a stop of light
3 clicks of aperture (in one direction) from any aperture value is a stop of light
3 clicks of ISO (in one direction) from ANY ISO value is a stop of light.
What is confusing?
Okay, let me get my Minolta SR-1 35mm SLR camera with the Vivitar 28-50mm zoom lens out of my camera bag...
I'm going to test your theory...
I've turned the shutter speed dial to say 1/60, ok, so I'm going to turn the dial 3 clicks up, okay so what have I got? It says 1/500, well would you believe it? That's actually 3 stops of a light!
Okay, I'm setting the aperture to say f16, I'm going to carefully turn the aperture ring slowly so I could feel 3 clicks... there, I felt three clicks, okay so what do it say, actually it's there's nothing marked there, well it's between f8 and f11, er, that's gotta be what? one and a half stop of a light right?
And please don't make me test your theory of 3 clicks = 1 stop with my Nikon D200, because I know mine is set to full stop setting so for me 1 click = 1 stop.
Your 3 clicks is 1 stop of a light for you and your camera, and also for anyone else using digital cameras set to use 1/3 settings,
but...
For other people who use manual cameras or digital cameras which had been set to either full stop or 1/2 stops, it is a different numbers of clicks for different numbers of stops.
3 clicks = 1 stop is confusing because like I said, when I tried 3 clicks, mine turns out to be either 3 stops or one and half stop.
The correct thing is to state that "
depending on your camera's settings or model, sometimes 3 clicks = 1 stop" not "3 clicks
is 1 stop"