ISO 100, f1.8, 1/6400 (late on a very sunny afternoon) Now that you have let go of the fear surrounding the M mode on your camera, it's time to explain the three main settings that ultimately work together to create a photo. Whilst this is a technical post I honestly believe that the best way to learn is to pick up your camera, play with the settings and take hundreds of photos. Don't rely solely on instructions; the best photos are taken by a photographer who has, in his or her own way, developed an intuitive approach to taking photos; essentially, the camera is an extension of the photo taker.
When you first take the leap onto manual mode, set aside a good hour to take photos. Ideally, you want to shoot in the early morning or late afternoon (for those of us with daylight savings, early evening is good, too) as the light is more forgiving at this time. Remember that one good photo out of 100 shots is commendable; don't set your expectations to high.
When I'm setting up a shot on my camera, I adjust the settings in the following order:
ISO basically measures your camera's sensitivity to light. Essentially, the lower the ISO (ISO100) the less sensitive your camera is, the higher the ISO (ISO8000) the more sensitive. So, during the day when you're shooting outside, you would generally set your ISO to 100 (the lowest setting). Indoor photography on a sunny day usually requires ISO400 and if you're shooting in low-light conditions, you would need to go even higher. However, the higher the ISO, the more grain you'll get in your photo (unless you're shooting on a top-of-the-range camera). Indeed, low light capabilities are one of the most alluring aspects of expensive cameras (and it's one of the main reasons I upgraded from the GF1).
if you're shooting outside set your ISO to 100, if you're shooting inside in natural light, set your ISO to 400. If you find that you still don't have enough light, take your ISO even higher.
Aperture has nothing to do with your camera and everything to do with your lens. Consider your lens your eye and the aperture as your pupil; it gets bigger and smaller as you adjust your settings, letting in more or less light respectively.
a large aperture setting is a large pupil, a small aperture setting is a small pupil
Perhaps what is most confusing about aperture is that the numbers work in the opposite direction:
a large aperture setting has a small number - f1.4 lets in a lot of light
a small aperture setting has a large number - f8 lets in much less light
Because most of you are reading this in the hope of taking more/better photos of your children, I would encourage you to set your aperture to either f2.8 or f4 so it's easier to get your subject in focus.
Aperture also controls the depth of field which is essentially the degree of blur behind your subject. As you can see below, I shot two photos of Che at the beach using two different aperture settings. A larger aperture setting - f1.4 on the left- will isolate the subject in the foreground and blur the background whereas a smaller aperture setting - f7.1 on the right - will bring the foreground and background into focus.
Shutter speed is essentially the exposure time; the length of time the camera's shutter is open to light. I wouldn't recommend shooting under 1/125 (of a second) unless you're using a tripod (or have very steady hands). This is particularly applicable if you're photographing people, especially wriggly children. Generally, a slow shutter speed will capture movement as a blurred motion but a fast shutter speed will freeze action with the upmost clarity.
As you can see below, a slow shutter speed of 1/640 has captured Poet on her scooter as "motion blur" where as a fast shutter speed of 1/2000 has frozen the water droplets from the garden hose.
There's a little bar in your viewfinder or on your screen that measures shutter speed - it's called your light metre. Ideal exposure is measured at "0" - an under exposed shot will be measured at "-1" or "-2" whereas an overexposed shot will be measured at "+1" or "+2"
But light exposure is a highly subjective matter. Ultimately, you control the look of your images by under exposing or over exposing, depending on whether you prefer a light-filled capture or a darker, moodier vibe.
ISO + Aperture + Shutter Speed
Notice that I've mention light a lot? Essentially, ISO, aperture and shutter speed work together to create your ideal lighting conditions.
When I'm setting up a shot, I'll do the following:
Set my ISO depending on the light conditions. If I'm outside I'll usually set it to 100, unless it's early evening, in which case I may shoot at 200 or 400.
Next, I select my preferred aperture. I love shooting at f1.4 but if I'm taking photos of the children and want to play it safe (ie. I want to make sure all or most of the subject is in focus) I'll shoot at f2.8.
And finally, I look at my shutter speed.
The slower your shutter speed, the lighter your shot will be. If you select a fast shutter speed, your photo will be darker. The best way to choose your ideal shutter speed is to take a photo and look at the results. If it's overexposed (there's too much light and everything is blown out) you will need to increase your shutter speed - make it faster - and vice versa if your shot is too dark.
If you find that you can't get your exposure right, you need to go back to your aperture or ISO. Granted, it can get a little confusing or overwhelming here but don't be put off. A few common scenarios:
If my photo is too dark, my aperture is at its largest (f1.4) and my shutter speed is 1/125 (and I don't want to go any slower than that), I'll increase my ISO.
If there is too much light, everything is blown out and my ISO is already at 100 (it's lowest setting), I'll usually increase my shutter speed. If it's still too overexposed I'll make my aperture smaller and move from f2.8 to f4.
ISO 100, f1.4, 1/640 (outside in early afternoon sun)
ISO 100, f2.0, 1/4000 (outside in midday sun)
ISO 500, f1.8, 1/250 (inside in the early morning)
I am in no way an expert at technical photography. Instead, I've explained these settings as I understand them - I hope it's been helpful! If you have any questions please ask them in the comments section.