At 09:01 AM 11/4/99 +0000, Dirk Wright wrote:
[snip]
>I've been feeling like a sucker since I browsed some filter web sites. This
>guy: http://www.2filters.com/ says that Tiffens are made with "green"
>glass, which he considers cheap compared to B+W and Hoya which use "white"
>glass. He also says that the Tiffen movie filters are made from white glass
>and are much more expensive. These are the ones they won the awards for.
>
>The issue of multicoating is still bothering me. I'm feeling foolish for
>having bought these tiffen uncoated filters when I could have bought Hoya
>multicoated ones. I thought Hoya was cheap, but the web site of the
>importer convinced me otherwise: http://www.hoyafilter.com/
Dirk:
No need to feel this way -- coating may or may not be all that important,
depending on what kind of filter you want and what you want to use it for. In
general, coatings are an attempt to introduce the absolute minimum degradation
possible in the image, but let's face it, many of Tiffen's filters are
special-effects filters which quite explicitly are designed to *introduce*
significant "degradation" (it just happens that this is a type of degradation
you actually want).
For instance, I own four of Tiffen's "SoftNet" filters (Nos. 1 & 2, in each of
black and white nets), and they "degrade" an image by softening it out --
really nice for portraits, but the contrast "suffers." (It's *supposed* to
suffer, since that's part of the effect I want.) I don't mind at all. On the
other hand, I'd *never* buy a Skylight 1A or 1B from Tiffen, since I have a
different purpose in mind for such a filter. In that case, Hoya HMC Skylight
1B is my filter of choice. I also use Hoyas for circular polarizers. They're
expensive, and worth it.
>I now think Hoya is the best deal for the money in a filter. B+W's are only
>single coated (mostly), while you can get up to a 5 layer multicoat on Hoya
>filters. Tiffen has only just started to re-introduce mc filters, since the
>early ones scratched easily.
You might be right. However, B+W has a reputation for using the finest-quality
optical glass (I don't know whether the rep is deserved or not), and they're
supposed to be dead flat, and I own a number of them in colour-correction
series as well as a few for panchromatic (full-spectrum black-and-white) films
which re-balance the B&W films' tonal range. I've always been pleased with the
results.
>What, if anything is the significance of green glass vs. white glass for a
>filter? The cheapest bottom line Hoya filters use green glass, the rest use
>white glass. I suppose that a filter manufacturer could compensate for a
>green tint in the glass when it designed the dyes, so the issue may be
>moot. Also, how significant is the fact that Tiffens are laminated, with
>the dye in the glue, vs. the solid glass of the others? Tiffen claims
>greater consistency for thier process and says that no solid glass can
>possibly equal the accuracy of thier filters.
No idea what the significance is re: green glass vs. white glass. I'd always
been under the impression that reputable filter manufacturers always used
optical-quality glass, with the best ones using rare-earth glasses with
extraordinary clarity (some of the glasses used for optical transmission lines
are so clear that you could theoretically see through a column of such glass
that was 11 kilometres deep!). As for the accuracy of the lamination process
versus tinting the actual glass and then polishing to dead-flat, who knows? I
would've thought with modern industrial processes that both techniques could
conceivably produce excellent results.
Garth
"A bad day doing photography is better
than a good day doing just about
anything else."
The Unofficial Olympus Web Photo Gallery at:
http://www.taiga.ca/~gallery/
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