Upgrading from a compact digital camera with automatic everything to a digital SLR means a steep learning curve needs to be climbed — at least if you want to fully exploit the creative options that full manual camera control provides.
Of course there’s nothing to stop you taking lots of bad photos to figure out what everything on a digital SLR does — there’s no film to waste, after all.
A better option, however, is to read up on bit of theory before you start snapping, but if you’re the kind of person who prefers to learn by doing here’s a web site that can help.
Camera Sim contains some brief explanation of what such terms as ‘focal length’ and ‘aperture’ mean when it comes to still photography, but the best bit is that there’s also a simulated camera viewfinder that shows the effect of various settings on an image.
So, fiddle with the controls and you’ll see how the camera viewfinder readout changes in order to get a feel for how such things as ISO speed and aperture settings are typically reported. Press the shutter release button and you can then see what the resulting photo would look like — and then try again if it turns out badly. The ‘image’ even contains a moving element so you can see the effect of different shutter speeds, too.