Help on manual settings?

So I've had the nikon d3100, and I tried using it on A to contol the aperture… But my pictures turn out blue-tinted ish… Not sure what's wrong?

And also for M manual setting, for just taking pictures of people (portraits) what shutter speed is the best? I'm new to this.

The blue tint likely is a white balance problem. Is your white balance set to auto? A sample shot would be very helpful.

The shutter speed should be fast enough for a steady shot and to freeze eventual subject motion. Since you don't want to specifically blur motion, you can increase the shutter speed at will if there's enough light. Or up to the flash sync speed if you use flash.

For the most part you'll want a wide aperture when doing portraits, like f/4. You also want to keep the ISO down, so the shutter speed usually is the variable that then is increased at will to keep the exposure proper.

I usually use aperture priority in bright situations so that the camera can increase the shutter speed according to the brightness of the motive. In less bright situations i use manual mode with ISO auto on, and set the shutter speed to the minimum that i need to reliably get a steady shot. The ISO automatic then sets the third variable for me.

Blue? Set White Balance to Auto.

Manual mode? Here. Learn.

http://www.illustratedphotography.com/basic-photography

Hannah, in order to properly learn to shoot on a DSLR, you should (and have to) read a basic photography manual. Just go to your local photo store such as Ritz/Wolf Camera and they will have one for you. You need to learn how to use the camera in full manual before you can effectively choose different auto modes other than full auto, which is somewhat pointless to own/use a DSLR if you don't use modes that require some amount, if not total, manual operation.

Mode A sets the camera to what is called Aperture Priority. As you appear to know, this allows you to set the aperture manually while the camera selects the shutter speed automatically based on your choice of aperture and ISO. This has little or nothing to do with your photos coming out blue.

White Balance controls colour of your photos. It can also be set automatically or manually. There are also presets for given lighting situations such as sunny, cloudy, indoors, etc. If your white balance is set to indoors or what is also known as tungsten, and you take photos outside, they will be blue.

There's no single correct shutter speed for portraits. You choose shutter speed based on if you are handholding the camera, the length of the lens and how fast your subject is moving. The lowest shutter speed you can use to shoot an animate object that is not moving too much is about 1/60th of a second but 1/125th is safer. Anything faster is fine too. If you are handholding the camera, you have to know the length of your lens to determine what your minimal shutter speed can be. It's easier to understand what shutter speed to use if you were using a 35mm film camera or a professional full frame DSLR. For your camera, you have to multiply the length of the lens by 1.5. This is the minimal shutter speed that you can hand hold this lens at without causing blur from camera shake. So if you are using a 50mm lens, your shutter needs to be set to 1/75th or faster. If you are using a zoom lens (which is not good to learn on) you need to look at the lens and see what length it is zoomed to and do the same. If your subject is moving, you need an even faster shutter speed which will be relative to how fast they are moving.

If you simply read a basic photography manual, all of this information will be in there and you won't have to learn it bit by bit as you randomly come up with questions/issues.

As also mentioned, I always recommend people use a 50mm prime lens to learn instead of a zoom. As you can see above a zoom makes calculating shutter speed a little more difficult and it makes understanding/predicting depth of field very difficult. The zoom lenses that come with cameras like the D3100 are also not quality lenses. If you enjoy portraits a 50mm 1.8 or 1.4 if you can afford it is a great investment as these lenses are partly made to take portraits.

I agree with what the others are saying, its more than likely that the white balance is off.

it seams your very new to photography so if you want to learn about shutter speeds, iso, aperture, whitebalance and all that other camera lingo i recommend purchasing a camera book called understanding exposure by bryan petterson.

i found a good price on that book at this site below

http://www.cameracity.info/popular-digital-cameras-and-equipment-of-2010

its towards the bottom of the page.

hope that helps you