To take pictures using manual on my digi cam. What and what for are important settings? How and when to use?

Answer 1

Shooting manual allows you to control your picture instead of the camera deciding, so kudos to you for taking that step.

The shutter priority mode, marked by TV on Canon or s on Nikon, allows you to select the shutter speed and the camera will select the aperture for a "proper" exposure. The aperture priority mode av on Canon and a on Nikon, lets you select the aperture (to decide how much depth of field) and the camera selects the shutter speed. Manual, you select both the shutter speed and the aperture.

Let's imagine that your picture is like a bucket you want to fill with water.. The hose pipe is the aperture, a bigger pipe lets in more water (or light) The faucet is the shutter, how long you leave it on (shutter open) You can get the same amount of water (your exposure) by adjusting the diameter of the hose or by adjusting how long you leave the faucet on. Either way will fill your bucket.

Your camera is numbered in f-stops to indicate aperture (the diameter of the opening in the lens.) A large aperture is a small f-stop number (like 1.4, or 2.8 etc) A small aperture is a bigger number (f11, 18, 22) Big aperture = less depth of field, and more light striking the film or sensor. Small aperture = less light and more depth of field. Consumer zoom lenses usually have smaller maximum aperture at the long end, the aperture varies with the focal length.. So they need longer shutter speeds to get proper exposures. Professional zooms are often 2.8 throughout their focal length, but they are large and heavy.

As your aperture gets smaller your shutter speed needs to get slower in order to get the same exposure.

Check your local library or bookstore for the book "Understanding Exposure" by Bryan Peterson.

Good luck!

Answer 2

Manual (M) on your digital camera is for when you want to select your own 'aperture' AND 'shutter speed'.
I mainly use M for when I want to shoot fireworks or a nightime scene because they require longer exposures and I want control of the aperture used etc.

You would select P (Program AE) when you want to adjust settings such as ISO speed, exposure compensation etc...but the camera selects the aperture and shutter speed to obtain a correct exposure from the adjustments you have made.
TV (Shutter Speed Priority) You select the shutter speed and the camera selects the correct aperture.
AV (Aperture Priority AE) You select the aperture and the camera selects the correct shutter speed.