mr. u. n. owen

when you use exp. comp. say +2 or -2 are you changing the f stop or changing the iso? are you adding at say +2 another stop to open up. a 3.5 lens now is a 2.8 ? anybody . thank you

Linda From Maine Loc: Yakima, Washington

If you are in aperture priority, the shutter speed changes. If you are in shutter priority, the aperture (f/stop) changes.

In other modes, I think it depends on the camera. What camera do you have and what mode/s do you use most often?

SharpShooter Loc: NorCal

Mr. @ +2 you add two full stops(exactly). At -2, again, two full -stops.
Cameras are generally set at the sdt. 1/3 stops but on some, in the menu, those values can be changed to other increments as well. But the standard is 1/3, as it's always been. ;-)
SS

tsilva Loc: Arizona

You can not open a lens more than its maximum aperture.

jethro779 Loc: Tucson, AZ

I don't think that answers the question. Which changes, iso or aperture when you set the compensation value?? That was what I thought he was asking. And I have always thought it was done by software and not iso or aperture.

Apaflo Loc: Anchorage, Alaska

That is not at all what Exposure Compensation does!

You have a light meter, which measures the light level and translates that to a "Light Value" that is given in stops of "Exposure Value" or EV. So if you read an external light meter, or look in the Exif data for your camera, you'll find the Light Value presented as something like 11.4 EV, or 13.7 EV.

At the base level, what Exposure Compensation does (and this is the only thing it does) is bias that Light Value reading by the number of EVs you set. Set it to +2, and what would have been a light meter reading of 12 EV is instead given as 14 EV. If Exposure Compensation were instead set to -1 EV that would read 11 EV.

Now, what happens as a result of taking a light meter reading depends on how the camera is configured. If you use Aperture Priority, the light meter reading sets the shutter speed as appropriate. And that will be different depending on what Exposure Compensation is set to. Shutter Priority, Program Mode, AutoISO and maybe other modes may all be controlled by the light meter reading, and if they are they will change when Exposure Compensation is set.

redhogbill Loc: antelope, calif

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Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

In the simplest terms, each unit corresponds to a full fstop. If you are shooting Aperture priority, specific ISO, it will adjust the shutter speed by the amount of the compensation you've dialed in. Many cameras have the option of using 1/3 stop increments, so you will see +.3, +.7 or +1 and vice versa. These correspond to 1/3, 2/3 or 1 full stop more light. So if your shutter speed is 1/250 and you dial in +.3 your shutter speed will be 1/200, and for +.7 it will be 1/160 and so on.

If you are in Shutter priority, with constant ISO, then the camera will adjust the aperture. Let's say you've set your aperture to F8 and you dial in +.3 - your aperture will open to 7.1; and +.7 will give you an aperture of 6.3.

If you are shooting auto ISO, and manual shutter and aperture, then the ISO will be adjusted up and down by the amount of the exposure compensation you dial in, as long as you are within the limits you set in the auto ISO range. There is a minimum shutter speed that is also figured in. Each camera is slightly different, this is how it works with a Nikon D800.

jerrypoller Loc: Huntington, NY

FWIW, I have a D7100 and shoot in Manual with AutoISO. If I adjust the compensation, my ISO changes, not my Shutter Speed or Aperture.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

:thumbup:

Correct!

camerapapi Loc: Miami, Fl.

Perhaps I do not understand your statements but I am certain NOBODY can use manual and auto exposure at the same time. You use one or the other.
It is not possible to shoot manual and use the EC bottom. If using the manual mode compensation has to be done manually also.
If I am wrong, please correct me.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Manual aperture and shutter speed settings, auto ISO. Actually 2/3s manual, if you want to be technical about it :)

camerapapi Loc: Miami, Fl.

Thank you.

jerrypoller Loc: Huntington, NY

Gene51 is correct. I select M(anual) vs A or S mode and set my ISO from the menu to AutoISO. So, I'm actually making 2/3 of the decisions, but the camera is still set to Manual.

camerapapi Loc: Miami, Fl.

I have never used Auto ISO. I made a test and set the camera to manual mode, aperture to f8 and shutter speed according to metering. It called my attention that the camera set ISO 400 for outdoor and indoor shots. Why?
Am I doing something wrong?
If there is an answer I do not want to keep this going in the forum and a PM with an explanation would be most courteous to others.