On Mon, 22 Feb 1999 18:22:35 -0800, Sam Ruby wrote:

>Any opinions on which manufacturers (Tiffen, Heliopan, or other) make
>the highest optical-quality filters for Canon lenses? At least, filters
>that can be used with Canon lens hoods and lens caps?
>
>I've used a cheap polarizer called a "Promaster Spectrum 7" for years
>with seemingly decent results, but I'm wondering if I'll need to
>"upgrade" when (and if) I buy a Canon "L" lens, such as the 17-35mm,
>28-70mm, or 70-200mm.
>
>Seems I ought to be concerned about putting anything other than a top
>filter on one of these expensive lenses.

There has been a lot of mythology about filter quality
built up recently (mostly by filter-mfgr. ads implying
that making a good, flat piece of glass is hard to
do...;-). The truth is that any reputable maker (the
common names...) makes flat enough filters for real-world
optical systems - the differences are in the coatings and
rims. Personally, I find metal-rimmed Hoya single-coated
filters fine for all but very particular uses (and some
"high-end" filters sometimes have disadvantages compared
with Hoya). I tend to avoid Tiffen, if possible, due to
the too-thick rim design and "spontaneous" fogging...
If you feel you must pay a lot of money for filters,
the Nikkors are hard to beat...;-) (As I recall, Canon
filters are actually made by Tiffen...;-)