Exposure compensation

[lblongs]

When photographing my daughter outside yesterday I ran into the following problem using natural light at 6 pm on an overcasy day. Using my 50mm 1.8 prime I was shooting at about 1/200 and 2.8 with my ISO somewhere in the 600 range. The images were dark and required me to bump the ISO to about 1000. I am not all too familiar with using my exposure compensation, but would this have been a time where I should have gone to maybe +1 instead of introducing noise from such a high ISO? I am still confused as to why perfectly natural light (it was not anywhere near sunset, but was overcast) and such a wide open aperture did not provide me the exposure I thought looked technically and visually correct. I did slow my shutter to 1/100 and got some better shots. I guess this is the point in which I realize I don't know as much as I thought I did.

[zona5101]

Changing your iso only shifts your values of aperture and shutter but the actual exposure is exactly the same as it was before you changed the iso. In this case you want to use exposure compensation in one of the auto modes or shoot in manual and overexpose the image.

[lblongs]

I shoot in full manual, and have never shot in auto. I'm pretty sure when I increase my ISO my shutter and aperture stay where I set them. I think.......right?

[dakwegmo]

If you're shooting in full manual mode, the exposure compensation dial doesn't actually do anything unless you have Auto ISO turned on, then setting your EV will change your ISO accordingly.

This article explains Exposure Compensation: http://digital-photography-school.co...tion-explained

[zona5101]

Originally Posted by lblongs

I shoot in full manual, and have never shot in auto. I'm pretty sure when I increase my ISO my shutter and aperture stay where I set them. I think.......right?

yes, they would. moving your iso would then increase or decrease the total exposure (same as exp comp). What I wrote in my originaly reply would not apply when you are in manual as your shutter and/or aperture would not corresponding change to the iso change.

So from your orginal post it appears you had to move your exposure 1 2/3 stops to get it right. Was the scene high contrast with a pretty bright area and the shadows you describe?

[Elmo]

ISO determines the sensors sensitivity to light, Increasing it increases the sensitivity. Depending on the sensitivity ther is only one EV that will give proper exposure. Different ISO (sensitivity) requires different EV for proper exposure. The combination of f-stop and Shutter speed determine the actual EV value arriving at the sensor. The arriving EV value must match the EV value expected by the sensor (determined by ISO choice).

Your meter will give you general EV value you need for your selected ISO. The catch is the neter will give you a value that will render the metered are a mid gray. Sometimes one will need to "compensate" for this. Suppose you have a landscape with a lot of dark areas and a little bright sky, The meter will make its reading and try to make the dark areas lighter (mid-gray) then the bright sky will be over exposed (blown out). in this case one needs to compensate by underexposing from what the meter says.

And yes I know you can use spot metering but bringing that up has only the effect of confusing the concept being discussed.

[PhotogChic]

Ok, this is only my opinion and just suggestions...I don't use Nikon so I hope these are similar. I usually shoot in manual (this is one of the few times I don't) as well and this is what I do when I need "natural light" shots in not so great light. It's pretty common to use a shutter speed no slower than 1/125 when taking photos of kids (not sure of the age...sorry). Anything slower will cause motion blur or camera shake if hand held, so 1/125 is the slowest I will go. I also switch to Tv mode so that I have a constant shutter speed and increase my exposure compensation to somewhere between 2 and 3...sometimes 4 or 5 (the highest my camera will go). ISO...I usually don't set it much higher than 800.

If none of these work...I use my speedlite on a low setting and off camera to get some "ambient' light but not make it obvious I used a flash.

I really hope this helps...