Camera Labs

Hello Everybody,

I recently upgraded my camera from Sony DSC h9 to Nikon D80, 18-135mm kit lens. Please help me out abt the exposure compensation and the apperture value.

what is the trouble you are having... do you need an explanation of what these terms mean and what they can do for you?... or do you need help on how to set them on the camera?

Aperture = opening of the iris in the lens. Controls the amount of light entering the camera, and also controls depth of field.

Exposure Compensation = specifically telling the camera to automatically attempt to decrease or increase the exposure value ("brightness") of the image when shooting in any type of "auto" mode (i.e. P, S, A) The exposure compensation is basically just underexposing or overexposing an image on purpose. Ideally, 0 is the "well-exposed" setting, and then -1 would be underexposed, while +1 is overexposed.

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Hi chaithanya, welcome to the cameralabs forums - I've moved your post to the dslrtips section as it's more relevant here.

I'd also suggest taking a look at our sister site www.dslrtips.com as it has several tutorials you'll find useful as a new DSLR owner, including aperture and exposure compensation.

Gordon

I would like to know in which situation i should over expose or underexpose, and when should i go for a bigger apperture and when should i go for a smaller apperture values

Hello Chaitanya! Nice to see an Indian name on these forums! (You are indian aren't you??)

Anyway, exposure compensation is a technique you'd generally use when your cameras auto-exposure sensor gets fooled, or sometimes to add depth to a shot.
Normally your camera will do a fine job of picking the right exposure for your shot depending on the settings you've chosen, and in whatever mode you shoot. However sometimes it can get it wrong, like for example if there's a large bright area in the image, such a bright window. or even if there's a large dark/shadow area in the image. In either case the camera may tend to under or over expose respectively, leaving you with an image thats either too dark or too bright. The good thing about DSLR's is that they have a much larger dynamic range, so these problems tend to be less frequent, and also even when they do occur, you can easily correct for it.

When an image seems too dark, just push the exposure compensation to the + side. A value of +1 generally gives an image twice as bright as that taken at level 0. And similarly -1 will give you an image twice as dark. Do a little experimentation with scenes like the ones i described to get used to how your camera handles different exposure settings.

Another place you might want to change the exposure is when taking sunset shots. Deliberately under-exposing a little can bring out greater depth in the colour of the sky at dusk/dawn and give you much more vivid shots. I'd suggest checking out the "how to take great sunsets" workshop at DSLRtips.com, and indeed all the other workshops posted there. They give some great tips and techniques which will be useful!

Enjoy your new camera!

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AJ

-Olympus E-VOLT E410
Zuiko Digital 14-42mm
Zuiko Digital 45-150mm

Thank you verymuch for your valuable suggestions

Forgot you asked about apertures!

Aperture value is a setting you'll be using a lot more frequently than exposure compensation, at least initially. In fact the "A" mode is one of the most you should be using most frequently in the initial stages of getting to grips with your DSLR. And even later you'll find its a very useful mode.

As somone mentioned earlier, aperture value denotes how much light you let in. "aperture" meaning opening, of course. Its like the iris of your eye. The wider the aperture (opening), the more light gets in and falls on the sensor.
One thing to understand though is that aperture value is denoted by f-number, and without getting too technical, the smaller the f-number, the larger the aperture. Most entry level DSLR's will go from an aperture of about 3.5 upto say 22. Although this varies based on the lens you have attached.

To keep it simple, when you change the aperture you generally change how much you have in focus. So you'll mostly be changing aperture for portrait shots and for landscapes. Changing the aperture is a great way to blur the background and get a great portrait shot. Here's how....

Basic principles - when you decrease the f-number (open up the aperture) you get less of your scene in focus. This is called shallow depth of field. When you increase the f-number (close/narrow the aperture) you get more of the scene in focus. This is called a large depth of field.
Now i'll explain things using only the terms shallow or large depth of field, to avoid confusion.

When you set for a shallow depth of field, only the subject of your composition will be kept in focus, the rest of the background (or foreground) will be blurred. How much blurring of course depends on how low and f-number you choose and also how much you zoom in. The maximum blur effect can be achieved by standing away from your subject and zooming in as much as possible. Remember you can blur both background and foreground this way. Just focus on your subject, half-press the shutter to focus, and then keeping the shutter half-pressed re-adjust the composition if necessary (but don't change the zoom once you've focused).

Large depth of field will give you more in focus. So if you want everything from the foreground to the horizon in sharp focus, just set for a large depth of field (high f-number) and zoom out as far as possible.

I's suggest going out with your camera and trying different combinations of aperture and zoom to see what you like... you can even practice this at home with a small statue and keeping it somewhere with a fairly distant background and trying to adjust the depth of field for different effects.

Again i also suggest checking out the workshops at DSLRtips.com!!

Hope i've been able to shed some light (forgive the pun!) on your problem...

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AJ

-Olympus E-VOLT E410
Zuiko Digital 14-42mm
Zuiko Digital 45-150mm