Good, because I was starting to think you suffered a major scam.

Greg

This has been an ongoing debate for decades.  I have come down on the side
of using filters for protective qualities, rather than lens hoods, which I
also use regularly.  The other side of the argument is this:

1: Lens hoods do not prevent dust, sand, mist or some finger smudges from
being deposited on the lens surface.  Filters effectively seal off the front
lens surface from these threats.  I rarely clean my lens front elements,
because the filters bear all the brunt of the dust/dirt, etc.  I would
rather replace a filter every few years than have a compromised front lens
element.

2: Many or us are using rare or expensive lenses.  In my particular
circumstance, I have numerous lenses, all in excellent condition, that have
not been manufactured for decades, and it would be difficult and expensive
to replace any of them in as good condition from the used market.  Erwin
Puts, the renowned Leica specialist, has estimated that a GOOD filter will
have no more than a 2% effect on the image, while other factors, such as
camera shake or off-axis light would impact photos much more than that
amount.  So, I accept the small loss of image quality as the price to be
paid for the added safety factor that the filter provides.

My own informal tests have not revealed any image degradation when using
filters.  Since I use Pentax lenses, I have always purchased Pentax-branded
filters.  They can be had on eBay relatively inexpensively, and Pentax has
been fairly consistent in making lenses that use a 49mm filter size, do it
is easy to stock filters that interchange on many lenses (one of the
advantages in not going with multiple brands of lenses--if your OEM brand
tries to maintain a consistent filter size you can save a lot of money,
since you don't have to buy multiple filters in different sizes).

Others may not share my view, and that's okay.  I have elected to place a
higher priority on protecting my lenses than rather worrying about a
negligible impact of the filter upon image quality.  It works for me.

I should mention that the links to the photos I posted earlier in this
thread were taken with a mediocre UV filter.  I haven't noticed a
vignetting problem with the lens and one filter.  Maybe if they were
stacked it would be noticeable.