lower iso=slower shutter. But what happens to the aperature in this configuration?

[nikonusersince2007]

If a lower iso like 400 is used vrs. iso of 800 then the shutter speed slows down, but what happens to the aperature during this exposure; higher F stop# like 2.4 or a lower F stop # like 11?

And what happens if this is reversed? If using a higher iso like 800 instead of iso 400 is used then the shutter speeds UP? But then what happens to the aperature during this exposure; higher F stop# like 2.4 or a lower F stop # like 11?

Thanks

 

[480sparky]

The aperture may not change at all.

Jumping from ISO 400 to 800 is only one 'stop', so you either increase the shutter speed by one 'stop' (i.e., 1/15 to 1/30) or close the aperture one 'stop' (f/8 to f/11).

 

[unpopular]

^^ yep. ISO is a measure of sensitivity, so if you double the sensitivity you need half the light in order to get the same exposure. If you half the sensitivity you need double the light. "double" or "half" is equal to one "stop" or "exposure value".

It does not matter how you compensate. If going from ISO 1600 to ISO 200, you'll need six times which is equal to 3 stops. You could increase exposure time, or aperture by three full stops, or you could accomplish this through a combination of both shutter speed and aperture - provided that your total compensation is equal to the change in sensitivity.

(oh, and I hate to be "that guy" but I think that most would agree that this really is a pretty basic topic)

 

[Garbz]

It's a balance of 3 things.

If you half the ISO you have to EITHER double the length of the exposure, or double the amount of light coming into the lens (increase aperture). You can do a mix of both i.e. drop the ISO by 1 stop [half], lengthen the shutter speed by 2/3rds of a stop, and open your aperture up 1/3rd of a stop to make up the additional light.

If your camera is in Auto mode it's anyone's guess as to what happens when you change your ISO. If you're in Aperture priority mode then the camera will change only the shutter speed unless you manually change the aperture, and if you're in shutter priority it follows that only the aperture is changed unless you manually change the shutterspeed.

 

[tirediron]

Search the term "Exposure triangle".

 

[SCraig]

Search the term "Exposure triangle".

What he said. If you are going to learn anything at all about photography this is the very first thing that should be on the list.

 

[Patrice]

^^

If going from ISO 1600 to ISO 200, you'll need six times which is equal to 3 stops.

I also hate to be 'that guy' but your math is just a wee bit off here. From ISO 200 to ISO 1600 is indeed 3 stops but that equals eight times the light.

200 to 400 is twice then to 800 is twice more and then to 1600 is again twice. 2 times 2 times 2 is equal to 8

 

[unpopular]

200 to 400 is twice then to 800 is twice more and then to 1600 is again twice. 2 times 2 times 2 is equal to 8

Nope. You're wrong. 2^3=6, not 8.

(Now, everyone agree. Lets see if that social psychology thing works online!)

 

[djacobox372]

Nope. You're wrong. 2^3=6, not 8.

(Now, everyone agree. Lets see if that social psychology thing works online!)

Nope, he's right

2*3 = 6
2^3 = 2*2*2 = 8

 

[unpopular]

YOU RUINED THE EXPERIMENT!

 

[brush]

200 to 400 is twice then to 800 is twice more and then to 1600 is again twice. 2 times 2 times 2 is equal to 8

Nope. You're wrong. 2^3=6, not 8.

(Now, everyone agree. Lets see if that social psychology thing works online!)

Yes yes, 2^3 = 6, absolutely.

 

[nickzou]

Did you just post this in Beyond the Basics??

 

[unpopular]

^^ see what AE does to people?

 

[480sparky]

2^3 = 2³ = 2 * 2 * 2 = 8.

^ and * are not the same.


2^3 ≠ 2*3

 

[unpopular]

No. But 2^n is the right formula, I was multiplying in my reply - hence the error.