Keeping it sharp
Your lens is the eye to your camera, and is used to focus light. Every surface and object reflects light and it’s the lens’s job to pass it through to your camera’s sensor to record the image. If you have a scientific mind and understanding you probably already have a good idea of how your lens is constructed and works, however most photographers may not even give it a second thought. Although you certainly don’t need a PhD in physics to take a great shot, it can help you get better results if you have some understanding about how your lens is constructed and what you need to be aware of when it comes to sharpness.
1 The basics
A lens consists of curved material, normally glass, that forms an image on your camera's sensor. But even a pinhole camera can produce a recognisable image, so what does a lens add? Essentially it can gather much more light, and focus it more sharply. However lenses inevitably include optical flaws such as distortion and chromatic aberration, which are addressed by using multiple lens elements (see tip 2), and increasingly by computational rectification. However nothing is perfect and these optical flaws are never completely eliminated, especially in cheaper lenses. As a result, we might get a result that we are not entirely happy with.
2 Lens elements
The elements inside your lens are
