On 2/25/2016 5:57 AM, John Duggan wrote:
Kowa Prominar 8.5mm f2.8 ?
Wish I could afford it!
I wasn't aware of that lens, or its siblings. I guess they aren't part of the
µ4/3 group? Not on the web site, anyway.
In any case, of no interest to me. I already have the M.Zuiko 9-18, which in only one stop slower @ 9 mm, infinitely
smaller and lighter, cost a lot less and has other FLs as a bonus.
Or, for about the same price, I could get the slightly smaller, lighter Panny 7-14/4. I just don't need the extra stop
in a super-wide and the wider end is a major benefit.
The Oly zoom @ 9 mm is not perfect wide open, but darn good stopped down a little. Photozone's test shows that the KOWA
is also soft in the corners, esp. wide open. I'm guessing little or no practical difference.
MF isn't a big deal at these FLs, but auto aperture is, to me. And getting the
lens data in EXIF is nice.
The difference between 8.5 and the 9 mm short end of the Oly zoom is tiny, and could, in fact, be reversed in any given
pair of lenses. Unfortunately, contemporary lens testers don't measure actual FL. In the occasional head to head
comparison one will see that the actual image field of two different lenses of the same spec. for FL will be quite
different, but no details, as these testers don't have test benches.
Back when Modern and Pop photo did lens testing, they checked actual FLs for their samples. Modern's criterion for
meeting spec. was ±5%. Their lab measurements for the samples of two OM Zuikos they tested were:
Spec FL Var. AOV
Zuiko 18/3.5 18.76 4.2% 98.1
Zuiko 21/2 20.15 -4.0% 94.1
Anyone with those particular two lenses would have, in effect, faster and slower versions of the same AOV. Someone else,
who hit the other ends of the range, might have 17 and 22 mm lenses.
The ±5% range for these lenses is
Spec -5% +5%
KOWA 8.5 8.075 8.925
Olympus 9 8.55 9.45
In any given pair, the Oly could be wider than the KOWA - or not.
So, Oly and Panny, where's that 7/4.0 rectilinear?
Just the Specs Moose
--
What if the Hokey Pokey *IS* what it's all about?
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