@Vetteran wrote:No, the lens does not need the filter - it's for the benefit, or otherwise, of what is behind it.
Just as a point of conversation, there are a couple of Canon lenses that require a filter to complete the weather sealing. The 50mm 1.2 L and 16-35L are two. So it could be argued that the lens does in fact need the filter.
You can argue that there is a perceivable impact to image quality, but trying to argue that a filter doesn't offer any protection to the lens is just asinine.
These two side-by-side photographs are examples of how nobody can positively tell which is which.
I frequently us this in my DSLR 101 class when people ask questions about the quality of filters or posting on the web or printing photos.
Both of these were printed at the same time on the same sheet of highest quality photo paper on the same printer. But here on a web site even more proves my point. “Most people” can not and will not be able to see a difference in filtered or non-filtered pictures. And even more differences, if not told so in advance. I guarantee there exist many differences between the two.
Most people are not pixel-peepers and they need not be. If you want to use a filter, use it. No one will know. If you don't want to use one, don't, no one will know. If you use one and feel it may cause a problem, take it off. It is easy.
