If you are concerned about the quality of your photo gear and want to step up to a more professional oriented kit, spend money on glass. It’s better to own the best lens you can afford than the fanciest camera body.
And don’t be fooled into thinking that only Canon, Leica and Nikon make good glass. There are plenty of good third-party lenses.
Here’s how to spot the signs of high-quality glass. Different manufacturers have different designations for it, but virtually all of them employ some kind of high-quality glass in their top of the line, and even some of their economy lens designs. Nikon lenses use ED glass (Extra Low Dispersion), Canon lenses use UD glass in their “L” series lenses, Tamron uses LD to signify their high quality glass, Sigma uses EX DG for their top glass.
These lenses exhibit better contrast, sharpness, and color fidelity. They also tend to exhibit less chromatic aberration. They may be more expensive (some are very expensive), but if image quality is important, the price is worth it.