Expose Yourself!

Ever wanted to get that little bit more oomph out of your shots, to get rid of those bleached highlights or murky shadows? Chances are its the exposure letting you down. So grab your camera, read on and be prepared to expose yourself!

Expsoure is the coming together of two wonderful things: shutter speed and appeture. Oh and a  third, minor hanger-on'er: ISO. What are these mysterious terms I hear you ask? Well, here it is broken down really quick...

The shutter is the click we here when we hit the shutter button; it is essentially how long the camera "sees" for. The faster the shutter speed the less light that enters the camera, the longer the more light. Why is this important? Well if you want to capture something like the movement of the ocean or the blinding strike of lightning then you need a loooong shutter speed. If you want to capture something that might happen in the blink of an eye or is moving really fast like a droplet of milk frozen mid air (it's far more beautiful than it sounds!) or the plume of a smoke stream then you need a really fast shutter speed to freeze the action. The shutter speed is measured in whole or fractions of a second eg 30s, 1/30s, 1/4000s, etc.

The appeture essentially mirrors the role that your iris (the coloured bit of your eye) plays in controlling the size of your pupil. The larger the appeture the more light is allowed through and logically the smaller, the less light. The appeture must be balanced with the shutter to allow for the correct exposure and there's a number of combinations that will result in a good exposure. Just as with the shutter, the appeture has an effect on the image: the larger the appeture the shallower the depth of field (ie less of the image is in focus), the smaller the appeture the deeper the depth of field (ie more of the image is in focus). Appeture is measured or referred to by the "f stop" number and just to confuse you a bit more, the smaller the number the bigger the appeture: f/1.8 (big hole), f/32 (small hole).

And a quick mention of ISO: this is the sensitivity of the sensor in your digital camera (or film in your coal fired, steam powered film camera!). The lower the number the less sensitive the sensor or film and the finer the quality of the image. The higher the number the more sensitive and the noisier or grainier the image.

Really that is it in a nutshell. There's probably just a couple more tips that might come in handy:

• A slow shutter speed will capture movement in a scene, but it will also capture movement of the camera itself. If you want to slow it down, make sure you have a steady rest like a tripod.
• If you read or hear about "stops" that is referring to, I guess what you could call a unit of exposure. One stop is the doubling (or halving) of either the shutter speed or appeture. If you have an exposure of 1/60s @ f/8 and you increase the exposure by a stop you end up with either 1/30s @ f/8 (careful of camer-shake!) or 1/60s @ f/4
• If you want to play around with trying to capture lightning or star trails (both of which usually requiring exposure in excess of 30s) then you're going to need a camera with a "bulb" function. This allows you to hold open the shutter indefinitely (well as long as your batteries will last) and unless you want to test out the stamina of your index finger, you'll also need some sort of remote.
• If you can't adjust the appeture and shutter speed on your camera (and with many point and shoot style cameras you can't) you can still control the overall exposure by utilising exposure compensation. This allows you to increase or decrease the exposure in set increments. The classic example of where this can be very useful is where you're taking a photo of someone against a really dark background and your first image comes out with the person really, really light; washed out and without detail. The exposure compensation allows you to force the camera to reduce the exposure, thereby getting a nicely exposed image of your BFF!

From here my suggestion is to play around and experiment with whatever settings you have available. After all that is one of the great benefits of digital; the results are always immediate!

Lightning over Junee. Two critical aspects to this exposure:
the shutter speed was in excess of 30s to give me the
best opportunity to capture the intermittent lightning, and an
appeture value large enough (small number remember!) to allow
the light from the lightning through.