Gary Reese always gets me going, so after his posts on autocollimater tests
and the rejection rates on filters, I decided to test mine -- on film. I'm
leaving for Utah next Friday and I want to know if I should bother taking
any filters.
I also used the roll to compare my Zuiko 28/2.8 and 24/2.8 to my Sigma
21-35. On that score, the Sigma seems to be equally sharp in the center,
but the Zuikos win the corners. I guess I should be happy that the zoom is
sharp in the center! All three lenses seem to have good contrast. Of the
three only the 24 is not MC, though it looks identical, except for the
small difference of perspective, to the MC 28/2.8. The lighting was easy
over-the-shoulder sunlight, however.
The filters I tested with two matched setups, one with my SC 50/3.5 macro
(for the 49mm ones) and the other with 90/2 for the 55mm's. The subject
was a blood red and yellow orchid against my black Webber patio grill. The
satin black enamel of the grill had a sizable bright reflection which I was
hoping would smear or flare if one of my filters was bad. I used the OM-4T
and set the exposure in manual mode from a spot reading off the flower. I
shot one frame without any filter with each lens as a reference for that set.
(This was the first time I'd ever put the 50/3.5 and 90/2 macros head to
head. Yes, the 90/2 is superior, but I have a hard time describing exactly
why, though certainly a combination of sharpness and contrast is the basic
reason. Yet the 50 is very sharp and very fine judged on its own terms. The
90 seems to cut diamonds, so to speak. This quality is only enhanced by its
splendid contrast. I can see why trying to determine where sharpness
leaves off and contrast begins fries Gary's brain. The distinction is more
theoretical than one realizes.)
The film was Provia. I used a 50/1.8 "lupe" (roughly 5x magnification) and
an 8X Peak.
The filters were:
49mm: Olympus L39 UV, Olympus 1A, Vivitar Series 1 VMC 1A, Vivitar
polarizer (thin)
55mm: Vivitar VMC UV-Haze, Minolta 1A, Hoya Skylight 1B, Promaster
Spectrum 7 1A, Hoya Circ. Polarizer
And now (drumroll) the results. They were all GREAT! I couldn't
distinguish the "naked" slide from any of those which were filtered. On
this same roll, I could easily see the difference between the 50/3.5 and
the 90/2, and between the Sigma 21-35 and the Zuiko 24/2.8 and 28/2.8 at
those focal lengths, but not even a hint that I was even using filters in
this particular setting.
Perhaps I am very lucky. Or perhaps my test setup was not useful for
purposes of exposing bad filters. I certainly wouldn't tend to use filters
(other than perhaps a warming filter) for macro. Comments anyone?
Joel Wilcox
Iowa City, Iowa USA
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