It's been a month since my last posted lens test. I only have 4 lens to post
about, although I also retested my 200mm f/4, with the same results as
previously posted. Looks like that puppy will have to go in for examination.
Maybe a little Zuiko elf put an element in wrong, or maybe it just isn't a
very good lens after all.
For a contrast, I've included 2 Vivitar Series 1 lenses. Thanks to everyone
who supplied lenses for this round of testing.
Gary Reese
Las Vegas, NV
*************
Olympus Zuiko and Vivitar Series 1 Lens Tests: Part 3
Gary Reese
December 18, 1998
Note: Set display to non-proportional font (ex. Courier) to view with columns
aligned.
* All tests photographed at 1:40 magnification ratio, on Fujichrome 64T film.
* Test subject: Grand Canyon National Park USGS topographic map (1 to 1 2/3
stop underexposure from a grey card reading).
* Subjective quality factor grades are relative with A+ = best, then B, C, D,
and F (worst); differences are significant across full letter grades only.
Corner grades are less rigorous than center grades, with A+ set to the
performance of a 50mm f/2.0 Zuiko Macro at f/8.
* Evaluations at 24X projection through a Rollei-Vario-Projar 70-120mm lens at
ca. 100 mm focal length
* Vignetting grades determined at full aperture only (expect where
pronounced): A = none apparent, tending towards D = more and more pronounced,
with D = unacceptable.
*******************************
18mm f/3.5 Zuiko (multi-coated)
Vignetting = C (f/3.5), B- (f/5.6), B+ (f/8), A- (f/11 and 16)
Distortion = None!
Aperture Center Corner
f/3.5 C C
f/5.6 B B+
f/8 B A-
f/11 A- A+
f/16 B A
Note: Vignetting characteristic of super wide angle lenses, improving with
stopping down; high contrast images; remarkable lack of distortion; lens
design emphasizes outer zones at expense of center image zone (which gives a
sharper overall impression of an image); overall optimum aperture at f/11.
50mm f/3.5 Zuiko (multi-coated)
Vignetting = B+
Distortion = None
Aperture Center Corner
f/3.5 C+ C-
f/5.6 A- B+
f/8 A A
f/11 A- A-
f/16 B+ B
f/22 B B-
Note: Good, although not high contrast image with softens beginning at f/11
and is distinctly softer at f/22, thus yielding best performace at f/8; soft
wide open; classic performance trends across apertures.
Vivitar Series 1 70-210mm f/2.8~4.0 (multi-coated)
at 70mm
Vignetting = B-
Distortion = slight barrel
Aperture Center Corner
f/2.8 B B-
f/4 B B
f/5.6 B+ B+
f/8 B A-
f/11 B- B
f/16 B- B-
f/22 B- B-
Note: High contrast images; remarkably even performance at 70mm through the
aperture range; difficult to determine effective aperture when shooting wide
open (click stops somewhat confusing); performance loss wide open at 210mm
characteristic of telephoto lens without ED type glass.
at 140mm
Vignetting = A-
Distortion = slight pincushion
Aperture Center Corner
f/2.8~4.0 B C
f/4 B+ B-
f/5.6 A- B
f/8 B+ B
f/11 B B
f/16 B B
f/22 B- B-
at 210mm
Vignetting = B+
Distortion = pincushion
Aperture Center Corner
f/4 C+ C-
f/5.6 B- C+
f/8 B- B-
f/11 B- C
f/16 B B-
f/22 B- C
28-105mm f/2.8~3.8 Vivitar Series 1 (multicoated)
at 28mm
Vignetting = D (f/2.8), B- (f/4), B (f/5.6)
Distortion = pronounced waveform
Aperture Center Corner
f/2.8 C+ B-
f/4 B B
f/5.6 B B
f/8 B- B
f/11 B- B
f/16 B- B+
f/22 B- B
Note: Waveform distortion characteristic of zooms without aspherical elements;
high contrast images; difficult to determine effective aperture when shooting
wide open (click stops very confusing).
at 50mm
Vignetting = B-
Distortion = moderate waveform with distinct tendency towards pincushion
Aperture Center Corner
f/2.8~3.8 C+ C
f/4 B- B-
f/5.6 B+ B
f/8 B B-
f/11 B B-
f/16 B B-
f/22 B B
at 105mm
Vignetting = B- (f/3.8, B+ (f/5.6)
Distortion = pronounced pincushion
Aperture Center Corner
f/3.8 B C
f/4 B B-
f/5.6 B+ B
f/8 B B
f/11 B- B-
f/16 B- B-
f/22 C B-
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