On Fri, 28 May 1999 PCACala@xxxxxxx wrote:
|Folks:
|
|This lens is so exceptional I had to post the results right to the list. I
|couldn't believe my eyes! Let the data and summaries speak for themselves.
|And don't miss what happens when you shoot with an OM-1n instead of a OM-4.
If I recall correctly, this lens was judged superior in sharpness to
the legendary Canon 200/1.8L. It would be easier walking around with
a 180/2 though---about half as easy, in fact.
|*********
|250mm f/2 Zuiko (multi-coated)
|Vignetting = C @ f/2, A- @ f/2.8, A @ f/5.6
|Distortion = None
|
|OM-4 w/ mirror and aperture prefire via the self-timer
|Aperture Center Corner
|f/2 A B+
|f/2.8 A+ A-
|f/4 A+ A
|f/5.6 A+ A+
|f/8 A A-
|f/11 A- A-
|f/16 A- A-
|f/22 A- B+
|Note: Extremely high contrast and resolving power at all apertures with only
|a minor loss in the corners at f/2 and f/22. Strong vignetting at f/2,
|requiring exposure compensation for critical work. Clearly one of the best
|Zuikos made. Brillant images, with f/5.6 showing a corner to corner clarity
|unsurpassed by any Zuiko tested to date.
|
|OM-1n with mirror lock-up and self-timer
|Aperture Center Corner
|f/2 D C
|f/2.8 D+ C
|f/4 C C+
|f/5.6 B- B-
|f/8 B- B-
|f/11 B+ B
|f/16 C+ C
|f/22 B- B
|Note: Combination of vibrations from the auto diaphram mechanism and the
|horizontally traveling shutter of the OM-1n results in significant image
|deterioration, despite secure tripod mounting the the lens bracket. Note
|that differences between this test and the one above with the OM-4 are
|significant at the 1/3 grade level based on side by side comparisons. Test
|conditions were identical and used the same lens.
|
|250mm f/2 Zuiko with Olympus 1.4x teleconverter (both multi-coated)
|OM-4 w/ mirror and aperture prefire via the self-timer
|Vignetting = C+ @ f/2, A- @ f/2.8
|Distortion = moderate pincushion
|Aperture Center Corner
|f/2 (2.8) A- B
|f/2.8 (4) A B+
|f/4 (5.6) A A-
|f/5.6 (8) A A-
|f/8 (11) B+ B
|f/11 (16) B+ B
|f/16 (22) B+ B-
|f/22 (32) B- C+
|Note: Moderate to moderately high contrast. Exceptional wide open
|performance.
|
|250mm f/2 Zuiko with Olympus 2X teleconverter (both multi-coated)
|OM-4 w/ mirror and aperture prefire via the self-timer
|Vignetting = D? (distinct central hot spot) @ f/2, B @ f/2.8, A- @ f/4
|Distortion = slight pincushion
|Aperture Center Corner
|f/2 (4) D C
|f/2.8 (5.6) B C
|f/4 (8) B C
|f/5.6 (11) B- C
|f/8 (16) C C+
|f/11(22) B- C+
|f/16 (32) C C
|f/22 (44) C C
|Note: Not an Olympus recommended combination. Unusable at f/2 (effective f/4)
|due to low contrast, poor resolution and hot spotting; moderately low
|contrast at f/2.8 to f/4 (effective f/5.6 to f/8), moderate at f/5.6
|(effective f/11) and beyond.
|*******
|
|Gary Reese
|Las Vegas, NV
|
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