In manual mode you have to set the aperture setting yourself and you have to set the shutter speed setting yourself. If the resulting exposure is wrong, then you are to blame, if it’s right then that’s a feather in your cap and you deserve a pat on the back.

So how do you know what are the right settings? That’s when experience comes in, and it is not something that can be learnt quickly. Experienced photographers will know that on a sunny day, with the camera set to an aperture of f8, that a certain shutter speed will generally give them a decent result but as there are so many variables to think about, it is a tricky thing to do. Luckily with digital you can experiment as much as you want without worrying about wasting film and money on learning and making mistakes.

As manual mode involves setting two parameters, it takes that bit longer to set the shot up, so if a quick shot is what’s required then a mode like aperture priority or shutter priority might be the better option so you can concentrate more on getting the picture rather than worrying about settings.

On the other hand, if you have the time to set the shot up then using manual mode will teach you the most. Set the aperture and shutter speed, take a picture, review it and see if it looks ok. If it’s under exposed (too dark) then you might need to slow the shutter speed down a bit or maybe use a wider (smaller) aperture setting. If it’s over exposed (too light) then you will need to do the opposite, speed up the shutter speed or reduce the size of the aperture by choosing a larger aperture value.

I don’t want to dwell on manual mode too much at the moment, it’s a bit like running before you can walk, but I thought it needed to be mentioned. Don’t be scared of it, just remember that it needs a lot more thought and experience to get right.

While aperture priority allows you to control the depth of field of your image, shutter priority allows you to control how motion of anything in the image is recorded. For example, for sports photograph, when you want to capture fast moving objects, using a fast shutter speed will help capture the action as sharply as possible. For landscape photography, on the other hand, you might want to use a longer shutter speed to create smooth looking water effects.  Fading light can also require a longer shutter speed when you want to continue using the same aperture.

This means the camera will select an ISO setting, Shutter Speed and Aperture for what it thinks is the best exposure for the conditions it can detect. Most cameras will allow you to override certain settings in P mode if you think it’s needed.

The P mode can be useful for people who are new to photography and don’t want to use any of the manual settings, and it can be good for getting that spur of the moment shot so you don’t have to worry about any camera settings and you just want to record the moment.

Using the P mode is fine, but exploring the other modes, giving you more control over the image, will help you produce better quality work and understand photography a lot more.

This mode allows you to control the aperture setting manually, but the camera will work out the suitable shutter speed to achieve, what the camera thinks, is a good exposure.

So what does controlling the aperture allow you to do, and why would you want to do it?

Aperture controls something known as Depth Of Field which is the area of the image that is in focus. The rule is that as the aperture number gets smaller, which means the hole is getting larger, there will be a smaller amount of the image in focus.

The following diagram is a fairly crude diagram which explains depth of field a little more.

The red line is the point where you are focussing the camera.

The grey area is the area of the scene in front of you that will appear to be in focus for a given aperture.

It should be noted that this is not an accurate diagram, it just demonstrates what happens when you change the aperture settings. It should also be noted that the change from in focus to out of focus is a gradual one.

So really, depth of field is the distance of that graduation from the point of focus.

Why is this useful?

Using a small depth of field is a great way to isolate the main object in the picture. Sports or wildlife photographers use this technique to blur out distracting backgrounds keeping the main focul point sharp. Using a wide aperture also allows a faster shutter speed to be used which again helps keep moving objects sharp.

Using a larger depth of field is good for landscape pictures, when you want the area close to you and the area far off in the distance to be in focus. Using a large depth of field means that you usually need to use longer shutter speeds which means that some form of support for the camera is required to keep the camera still which the shutter is open. You will rarely see a landscape photographer without a tripod.