Thanks for your comment firstly. The basic skills to use an SLR is indeed the aperture, shutter speed and ISO. It is an area that can be explored in a full article. I’ll try to be brief and practical.

Using the z20 you should be able to practice your manual exposure control quite well, I used to use the A1 myself as my first digital camera.

Regarding the ISO, generally you’ll want to use a lower ISO like 100 or 200 to minimize the amount of noise in the image. The lower the noise, the better quality your prints will be if you enlarge it. The ISO controls the sensitivity of the camera sensor, how receptible is it to light. The higher the number, the more sensitive the sensor will be.

The aperture is how large your lens aperture blade opens up when shooting, the larger it opens up the more light it allows in (to the camera sensor), the brighter your picture will be. Generally the smaller the numbers (f / 1.4 or f / 2.8) the larger aperture.

The shutter speed is the length of time in 1/X s your camera opens up allowing the light to hit the camera sensor. The longer the shutter opens, the more light your sensor “absorbs” the light, the brighter your image will be.

So there is no set settings for one fine day, it all depends on the light condition on the day. Play with the aperture and shutter to allow the amount of light that can enters the sensor for a lower ISO. As a generic rule, the smallest speed that you can use to avoid blurring by movement is 1/lens length. So if you zoom in to 60mm then the lowest speed you can use is 1/60s.

If you can’t get a good image with the current ISO that you are using, then you have to increase the ISO.

gabriel