I carry two types of filters. A variable neutral density and a polarizer. To save a few bucks I use step down rings. I use step down rings with the largest filter size I need. Usually, that would mean one size fits all. Excellent filters, made from excellent optical glass are not cheap. These two filters are more or less specialized in controlling light. Neutral density filers cut back light so you can get to slower shutter speeds but have no effect on the color of the image. Polarizer filters also cut back light by about 2 to 2.5 stops, eliminate reflections and deepen color.
But this blog is about the most basic of filters. UV filters, Skylight filters and Clear protective filters.
Many years ago when I purchased my first lenses, the choice of basic filters was to “correct” the effects of Ultraviolet Rays on film, which are prevalent in overcast and hazy lighting conditions. Therefore they are called UV Filters. In that same time period there was and still is another filter called Skylight. This filter also corrected for some ultraviolet but also produced a very slight warming effect. Photographers usually choose one or the other and stayed with it as part of their shooting style. As time moved forward and technology in regards to lens coatings did the same, photographers felt that the UV issue was covered in the lens coatings. Overtime, the UV filter became the protective accessory that no one should be without. The UV filter now became more important as a means of protecting front elements as opposed to correcting for UV light. Then came the neutrally clear filters which did nothing but protect.
So here is where personal opinion comes in. Please remember that it is my opinion and there are others that differ. No matter what anyone believes to be true or not true or partially true is of no consequence. What is important is the quality of the filter if you decide to use one. It must be one of excellence. It must be equal to and better than the lens you are putting it on. Buying a cheap filter is like shooting through a Coke bottle. Who makes an excellent UV filter? Zeiss, Heliopan, B+W, Calumet made by B+W.
I believe that UV filters are still necessary to block UV light when shooting in hazy conditions. WITH FILM.
I believe that under certain conditions such as being on beaches with blowing sand, salt water, highly polluted areas, muddy forest trails, skydiving, and the like could require protection of the front elements.
Rainy and misty conditions.
Digital Camera sensor are no where near as sensitive to UV rays as film. So for digital cameras we are looking more at a piece of glass for protection as opposed to image enhancement.
I have used UV filters on my lenses for as long as I can remember. Having been in the photography industry for many years I grew into the philosophy that UV filters needed to be a permanent part of the lens. It was the only way to protect against UV issues and too protect front elements. Back then there was very little thought given as to the effect that the extra piece of glass might have on overall optical quality.
Today, a battle goes on about the image quality with and without the filter on the front. One school of thought says it does not effect the optical quality as long as it is an excellent filter. The other school of thought says that the optical design of the lens today is highly complex and the addition of one more surface will create quality issues. That was probably viable 50 years ago as well.
What do I do?
I carry UV filters for all of my lenses and use them if shooting conditions require if I find myself in a situation where the front element might be damaged.
I have become a part of the school of thought that putting the additional piece of glass in front of the front element could affect the image quality edge to edge.
More important to me, is the lens hood. It not only affords you a great deal of protection from stray light, but from bangs and dings you may encounter on your quest for the perfect image.
Finally. Front lens caps and rear lens caps. USE THEM PLEASE.