After reading your response it occurred to me that the ranges might have
been chosen for optimal resolution to suit the smaller than 35mm 4/3
sensor. However, I've just convinced myself that it only has to do with
metering. I haven't done all of them (only up through all the primes or
zooms starting at 50mm or less) but Oly's recommended aperture ranges
for the lenses I checked have a very poor correspondence with optimal
performance as shown in Gary's lens tests. Optimal resolution and
contrast on Gary's tests are very often achieved at apertures smaller
than Oly's recommendations and, on rarer occasion, larger. There are a
few which do correspond fairly well but, for the most part, no. For
best optical performance I think you need to pay attention to Gary and
ignore Oly's advice.
Later note: Aware that telecentricity might be rearing its head in the
shorter focal lengths I decided to check the longer ones as well. I'd
say the correspondence is a bit better but not convincing for an optical
quality hypothesis.
For Matt and any other new comers the reference is to an extensive
series of tests of Zuiko and non-Zuiko OM mount lenses conducted by
former list member Gary Reese of Las Vegas. All OM users should be
aware of them <http://members.aol.com/olympusom/lenstests/default.htm>
Chuck Norcutt
Andrew Fildes wrote:
> Except for the big whites of course so it may be a quality issue.
> Andrew Fildes
> afildes@xxxxxxxxxxxxx
>
>
>
> On 11/11/2007, at 10:46 PM, Chuck Norcutt wrote:
>
>> Unfortunately, Olympus has never said why their recommended aperture
>> ranges are so narrow. Is it exposure metering?
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