There is almost certainly a positive relationship between brand/price
and the odds of getting a good filter, but brand and price aren't
guarantees.. Take a look in Gary's tests
<http://members.aol.com/olympusom/lenstests/default.htm> at the paired
tests of a "50mm f/1.4 Zuiko (multi-coated) OM-2000 with mirror and
diaphram prefire; lens with >1,100,000 serial number" with and without a
bad filter. and note his comments:
"Contrast was slightly lower with the filter, but lower resolution was
the most important factor in image deterioriation. Please note that this
particular filter is not indicative of Vivitar or Vivitar VMC filters,
in general. It just tested as a poor sample. Other filter makers, even
the most highly regarded, have been found to have poor samples in
selections taken from used and new stocks of filters. The use of the
term "poor" means star test images, viewed on a vertical auto
collimeter, which show images that are: multiple and overlapping, fuzzy,
off center, and images which rotate when the lens is rotated. More often
than not, only one of these faults are found in an examined filter.
These filters (including the test filter) often look perfectly good when
examined without the aid of instrumentation!"
I think a good strategy is to buy name brand MC filters and do a couple
of with/without tests, including one with a bright point light source
and one with fine detail, before relying on it for important shots. My
general rule is not to use filters except in hostile environments or
where the filter is part of the photographic process, rather than just
lens protections. Otherwise, I use hood and lens cap to protect the lens.
The top brands also offer some non-optical features like thinner
filters, brass filter holders, which are less likely to bind, etc for
the premium prices.
Moose
Danrich wrote:
Has anyone done any testing or know of a report of the quality
differences between a B&W down through the cheapest filter in UV
category?
The Price of a 67mm UV Filter goes from $60. to $5.
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