In article
>In article <5e1tac$1j9@newsstand.cit.cornell.edu>, d_ruether@hotmail.com (Bob
>Neuman) wrote:
>> In article <5e0o15$d63@lastactionhero.rs.itd.umich.edu>, calvin@umich.edu
>> says...
>> >>If you are going to use a UV filter for lens protection, you should spring
>> >>for a B+W multicoated one. I have one, and it's about as harmless to the
>> >>image as you'll ever get. Reflections are extremely low in amplitude, and
>> >>the glass is clear and flat too.
>> >>If you cannot afford to buy it, then your lens is probably not worth
>> >>protecting either.
>> >I am looking for the best filter to protect the lens of my Konica
>> >Hexar. Which one would you recommend? Please specify size and
>> >make.
>> This keeps coming up, but......
>> An inexpensive Hoya multi-coated filter, for ALL *practical* purposes,
>> is as good as is required for the most critical use (NO discernable image
>> sharpness degradation...). If you feel that you must spend more money,
>> the Heliopan and B&W filters are equally good, as are the even more
>> expensive, excellent (and equally good...) Nikkor filters...
>> And BTW, UV filters are protection devices only - they do not "cut haze"
>> (since most lenses themselves do not pass enough UV to matter).
>> Hope This Helps
>Don't really know how you came up with
>> (since most lenses themselves do not pass enough UV to matter).>
'Cuz 'tis fairly well (and generally) known that there is generally some
UV absorption by each lens element - and when there are about four (or
more...) elements in a lens, the absorption level is sufficient to make
the use of UV filters redundant for UV filtering purposes under most circumstances...
>But UV filters certainly do cut haze and they cut the haze prior to any
>effect the lens may have as they are in front of the lens.
But we care about the effect of UV on film..., not where in the optical
system the UV is stopped, so long as enough of it has been filtered out
*somewhere* in the optical system before it hits the film.
>Secondly a UV filter is slightly yellowish. If the lens was as effective
>as the UV filter you would very likely end up with an overall yellow cast
>from the combination of the UV filter + the lens correction. You do not.
Well, actually, you do - but the color is sufficiently subtle for it
to be overlooked. Also, one could, with a very sharp-cutting UV filter,
theoretically filter out all UV with no visible coloration. Also, even
with non-sharp-cutting filtration, a high percentage of (invisible)
UV can be filtered out with little yellowness evident in the optics.
>In any case the standard UV is only the basic, weakest correction
>possible. Stronger UV types are used for B+W as they are too yellow for
>color.
Yes - but this may not be necessary. Try taking two photos under
identical conditions of lighting and haziness, both with the same ordinary
6-element lens, but one with, and one without, a UV filter. I dare you
to discern any difference, even if you use B & W film and the strongest
UV filtration. Heck, even add a light yellow filter under hazy conditions
(total UV absorption likely by the filter), and you MAY (or may not...) be
able to discern a VERY slight difference in the images...(assuming proper
exposure correction for the filter absorption, and lack of strong blue in
the subject).
>As for your comment:
>
><> An inexpensive Hoya multi-coated filter, for ALL *practical* purposes,
>> is as good as is required for the most critical use (NO discernable image
>> sharpness degradation...).>
>
>How did you arrive at this conclusion?
>
>You have personally tested the brands head to head at the same time or you
>believe that your statement is true without having actually compared them?
>
>Bob
>HP Marketing Corp. Gepe, Giottos, Heliopan, HP Combi-Plan-T, Kaiser, Linhof, R
>imowa, Rodenstock, Rollei, Sirostar 2000
There is no need to do that... If I establish that (relatively inexpensive) filter brand X (through testing) is (for all practical purposes), optically
perfect (and it has a good-quality rim), there is no need to compare it directly with any other (possibly MUCH more expensive) filter brand. Being a seller of fine, expensive filters, you may not want me to say this, but in
my experience, an inexpensive Hoya multi-coated filter, for ALL *practical* purposes, is as good as is required for the most critical use (since there
is NO discernable image sharpness degradation resulting from its use under
most circumstances, even very demanding ones, so there is nothing to be
gained by spending more money on another filter...).
Hope This Helps