I Bought a Digital Camera but my Photos are Still Blurry
There's a common idea that digital cameras make photography easier. While this is true in some ways, at the core digital photography is still photography. The basics still matter.
In order to record a photographic image on either film or digital media, light is necessary. And it takes time for that light to do its job. While the shutter is open, light falls on the media, and where it falls, it leaves its mark. For an image to register as sharp, all of the light from it needs to fall in exactly the same place in the frame. If it doesn't — if the camera moves during the exposure or the subject does — you'll get a blurry image.
If the shutter speed is fast enough, you can get away with a lot. In a short space of time, things just can't move all that much so in bright daylight, hand holding the camera can work quite well. But many of the best nature photos are taken at the edges of light near sunrise or sunset when there is significantly less light in the sky and exposures have to be much longer in order for anything to register at all. A tripod becomes a necessity at such times. At high noon you can reasonably just fire away for most needs but a tripod can help even then both to ensure you get the sharpest results you can and also to allow you to concentrate more on your compositions.
It's also important to use the best lenses you can since they are what focus all of your images onto the camera sensor. A cheap camera with a good lens is a much better investment than an expensive camera with a cheap lens. A camera is fundamentally a light-tight box with hole in it for the shutter and an accurate timer that controls how long that hole stays open. A lens is an optical instrument that actively affects the path of light as it travels from your subject to its destination in forming an image of that subject. Using a cheap lens is somewhat like trying to look at the world through coke-bottle glasses. Things are going to look blurry no matter how steady you hold them. The same holds true for filters if you use them. Your images will come out no better than the weakest link in your optical chain. A ten dollar filter placed in front of a five hundred dollar lens is going to make all your images look cheap.
How that lens is focuses matters too of course. A lens is always focused only on a flat plane some given distance in front of your camera. Choose that distance wisely as determined by your subject. Known as depth of field, any apparent zone of focus in front of or behind that plane is a fringe benefit of your chosen lens aperture and other factors. If you want a greater depth of field, you'll likely want to use a smaller aperture (which counter-intuitively is designated by a larger f/stop number). Of course, if the opening in your lens is smaller, you'll need to leave it open longer to get enough light on the sensor to record an image, which leads us back to shutter speed and the need to keep your camera steady while taking a picture. It's all related.
When using a digital camera, you can see your results on the LCD back panel immediately after each shot. If you shoot with a long shutter speed or with flash, you can see what your eyes normally can't. With film, you had to wait until your negatives or slides were processed to know if you got the shot. Digital also lets you see what settings you used for each shot so that if something worked out you can do it again, and if things didn't turn out as you expected you can learn from your mistakes quickly. The histogram tells you a great deal about how the camera reacted to what you were photographing — whether you over or underexposed it and so on. But with all that and much more, digital photography is indeed still photography. Take the time to learn the basics and you will be much happier with the pictures you end up with.