I heard good things about Marumi filters but the price is not much
different from B+W. I'm not in the market for any filters but, if I
was, I'd be inclined to try something middle-of-the-road price-wise or
even lesser and test it to see how it performs.
Years ago, Gary Reese reported on numerous tests of filters conducted by
him and a friend who owned a camera store. The store owner had a (IIRC)
"star tester" (whatever that is) and they applied it to numerous filters
almost all of which failed. I've always wondered what this test device
was and whether its results were at all relevant to real photographic
images. How much error can be induced by a single piece of glass that
is not perfectly plano parallel? I dunno and I dunno if it really
matters. I don't know that I've ever seen a comparison of a high
mangnification photo taken with a B&W filter and a cheapy ebay filter.
I'd like to see one to check it out.
On a related note I have the same sort of comments on the tests of lens
adapters reported by Roger Cicala at lensrentals.com. He complained
bitterly of inexpensive lens adapters whose two mount faces were out of
parallel
<http://www.lensrentals.com/blog/2013/09/there-is-no-free-lunch-episode-763-lens-adapters>
What in the world is he actually testing? A different blog referenced
there says "The errors in question need only be 5 microns before MTF
(contrast) begins to drop, with errors of 10 microns or more displaying
as visible blur. It’s not even clear that the lens mount on DSLRs has
that kind of precision."
I think I can state quite strongly that I doubt that the original
lens/camera mount faces are machined to such high standards. To expect
adapters to exceed then is silly. I don't think microns are the normal
measurement unit. And if tilting the lens even 10 microns causes such
horrible errors what to we have to say about tilting the entire lens 7
degrees using a tilt=shift mechanism. Oh, the horror of it all. Hint:
The perfectly *flat* test image is blurred because the plane of focus
has shifted. No big deal for real world photography.
Chuck Norcutt
On 3/1/2014 11:59 PM, NSURIT@xxxxxxx wrote:
> When looking at eBay for filters there seems to be about 5 or 6 brands,
> each of which comes from someplace in Asia. Does anyone have any positive
> experience with any of this current batch of purveyors? My interest is in a
> UV, Polarizer and possibly a variable ND. They would need to be thin
> filters as the lenses I would be using them on are pretty wide. Although I
> own
> some high end filters I'm not interested to spending the big bucks on
> these.
>
> Bill Barber
>
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