I don't know about you, but many of my best photographs are from some time ago when I was using equipment that is not near as technically good as today's equipment. It would seem as if some things that led to great photographs in the past are being lost in today's choices. Today's lenses are technically very good, yet in many cases are approaching a level of perfection that to some extent takes away from the character of photographs, especially as more and more photographers seem to be after a crispness, sharpness, and loss of distortion across the entire image. If we all could afford the technically best lenses, shoot them at the F Stop the produces the best technical image, and they were all easy to use - what would that do to the world of photography? The rule of thumb for decades has been 1-2 steps down from wide open will produce the sharpest results. This rule of thumb is starting to fade, but is it important to shoot at the F Stop that produces the crispest and sharpest image across the area of the image? Which often leads to - What is the best lens? While to some this is the way to photograph, I think it very important to get to know how each of your lenses work at various settings taking advantage of the lens characteristics. Lens characteristics of photographic lenses come from bending light rays and trying to focus the rays on the image plane recording onto a small area - hence lenses always produce distortions in the process of bending the light rays. The best a lens can do is to correct as many of these distortions as possible. The nearer to perfection, the more the cost and the larger the lens size. Image quality is largely a result of lens characteristics. Aside of the physical aspects such as size, weight, build quality, focal length, and maximum aperture lens characteristics include: astigmatism, barrel distortion, bokeh, chromatic aberration, clarity, color reproduction, coma, contrast, depth of field, field curvature, field of view, flare, ghost, light transmission (amount), micro contrast, perspective, pincushion distortion, resolution, spherical aberration, tone, vignette, and how all these play out across the image. The closer a lens gets to perfection of these characteristics, the less character the lens produces as the image becomes more pure and sterile. Some photographers try to produce outstanding images simply by procuring the best equipment - which is often the talk of many conversations based on what is the best lens. One thing a photographer can do to set their photography apart from others, is to best use lens characteristics to their benefit. Some lenses may take a considerable amount of experience with them to exact the best image possible from them, and in some cases that may mean that a lens is only great in certain circumstances. But asking what the best lens for X, is not necessarily the right question. Although this was written based on lenses, I think it generally pertains as well to the cameras we use. To produce the best images does not require the technically best equipment! The final photograph is after all based the photographers knowledge, and how that is used with the equipment they have.