The basics of manual control

So, you just got a dSLR or and advanced point and shoot, now what?  Well, unless you already shoot in manual mode (The "M"), you really aren't gaining much over your previous camera because the camera is making almost every decision about the picture.  Before you can go and shoot in manual mode, you have to understand what the controls and settings do and how that effects your picture.  There are 3 major things that you have to set in order to make a good picture.

1 - ISO
This was formerly to "film speed", but now it relates to how sensitive you are setting your camera's sensor.  Common ISOs are 100, 200, 400, 800, 1600, and with very sophisticated dSLRs 3200, 6400, etc. (my camera doesn't have anything past 1600).  The higher the ISO the better you will be able to shoot in low-light situations.  The problem with using high ISOs (I consider that 800 and above) is that the higher the ISO the more noisy (or grainy) the image is going to be.  On sunny days I would use ISO 100-400 because I have a lot of light and therefore a low ISO will be better so I don't get much noise.  Cloudy days I would normally use ISO 400, still pretty noise free, while still allowing me to use fast shutter speeds (explained below).  Night photography I always use ISO 1600, because there is just not a lot of light.

2 - Shutter speed
For me to explain this, let me tell you what happens when you take a picture.  First the mirror that diverts the image from the lens to your Viewfinder goes up, the viewfinder goes black, and then the shutter that shields the sensor from light opens and then closes after the image is taken.  The shutter speed is how long the shutter is open for and thus decides how long the light is exposed to the sensor which records the image.  On a sunny day you'll be able to choose a very fast shutter speed such as one two thousandth of a second (just for scale, that's about 150 times faster than you can blink your eye).  On a cloudy day probably 1/400-1/800 of a second, and in your house maybe 1/4 of a second, at night you'll want to take a picture at several seconds.

Now here's an exercise for you, set your camera to "shutter priority mode" or "Tv" as it is on my Canon camera.  First set the shutter speed to 1/400 second and take a picture, now take that same picture at 1/4 second and review both on your camera's LCD.  You'll notice that the second image is A LOT blurrier, why is that?  Well it turns out that the longer the shutter speed is, the blurrier the image is going to be.  A rule of thumb is that if you are using a 50mm lens, you'll want to use a shutter speed of 1/50 second or faster, the same goes for different focal lengths.  For an 125mm lens, use a shutter speed of 1/125 second or faster, etc.

3 - Aperture
You see that number next to your lens focal length?  It will be something like ƒ/2.8 or ƒ/4, that's your lens' aperture.  That tells how much light your lens can admit at a time, there's a funny thing about it though, the SMALLER the aperture the MORE light your lens can gather at a time.  Think of it this way, your sensor is like a bucket and to take the picture the bucket needs to be full, the aperture of your lens decides how big of a measuring cup you get to use.  If your lens has an ƒ/4 next to it, you get a 1/4 of a cup measuring cup, if your lens has a ƒ/2 next to it you get a 1/2 cup measuring cup.  Which is going to fill the bucket faster?  The ƒ/2 with the 1/2 cup measuring cup of coarse, it'll finish twice as fast.  Now, fast lenses we will say have an aperture of ƒ/4 or faster, they are much more desirable because they allow you to use faster shutter speeds.  And now, as we know, faster shutter speeds are better because it makes the image less blurry.


Another important thing - The light metre
Now you're probably asking "ok, now how do I know what to set those at to make a good picture?", there is no absolute answer to that because of different lighting conditions and many other variables.  But one thing that you'll look at for every picture is the light metre, on my camera the Canon EOS 400D it is located on the viewfinder as well as the LCD, on en.wikipedia.org/wiki/Image:Ca… the light metre is the number line that shows:

-2_ _ _ _1_ _ _ _0_ _ _ _1_ _ _ _+2

the -2 side of the 0 means the image is too dark, the +2 means the image is too light.  You'll usually want images to be on the 0 so you have a perfect picture, that is unless you want a darker or lighter picture.


And now we've reached how far I'm going on the basics of manual control, if you have any questions or find anything confusing don't hesitate to ask!  I'm always looking to make my journals more informative and useful