If you use Flash as the main light source of course, all the vibration is
eliminated. It would
have been nice to see Gary's tests done with flash too.
Tim Hughes
--- Chuck Norcutt <chucknorcutt@xxxxxxxxxxx> wrote:
> But it's not so random as you make it sound. The major distinction is
> whether the test was conducted on a body that allows mirror and aperture
> pre-fire with self-timer. The mirror flipping up is one source of
> vibration but just as troublesome or more so is the kick of the aperture
> lever closing down the lens. Unless both of these vibration sources are
> under control you're not getting a real test of the optical performance
> of the lens. Not included in any of Gary's testing was something to
> control shutter vibration. We don't know how the results might have
> differed if he draped one of Walt's bean bags full of lead shot over
> camera and lens.
>
> Sometimes there are significant differences between very early and very
> late models of a lens and ususally minor differences between two
> different samples of the same lens. The grading is very strict. I
> don't think most people would notice sample variations... unless they're
> testing lenses. :-)
>
> Chuck Norcutt
>
> keith_w wrote:
> > Chuck Norcutt wrote:
> >
> >>I think the distinction we're talking about is not multicoating but the
> >>optical performance of the lens which changed through the years as
> >>Olympus made various engineering modifications.
> >>
> >>Multicoating is just one of the modifications and doesn't mean the same
> >>thing for all lenses or all versions of the same lens. Two different
> >>versions of the same lens known to be multicoated may have different
> >>types of multicoating and may have different numbers of their elements
> >>multicoated. Some elements may be single coated even on a lens marked
> >>as multicoated.
> >>
> >>Most of this stems from Gary Reese's extensive testing of Zuiko (and
> >>other) lenses. Gary often tested multiple samples and versions of the
> >>same lens. When interpreting these test results you also need to be
> >>aware of the body used and any other supplemental support on long teles.
> >> The Zuiko 200/4 is especially prone to vibration but is an excellent
> >>performer if suitably restrained. Vibration is a signficant factor in
> >>all of these tests and best results are typically reported using a body
> >>that allows mirror and aperture pre-fire with the self-timer. Gary
> >>clearly proved that just locking up the mirror ala OM-1 isn't good
> >>enough for critical testing of lens quality.
> >>
> >><http://members.aol.com/olympusom/lenstests/default.htm>
> >>
> >>Chuck Norcutt
> >
> >
> > Interesting comments, Chuck...
> >
> > After I spent a good bit of time looking over Gary's site, trying to absorb
> > as
> > much of it as possible, all i was left with was shaking my head, and
> > realizing
> > that "lens tests" are only as good as the paper they're written on, and at
> > that time of day! :-(
> >
> > I'd find a lens that performed exceptionally well on, say, an OM-2. Then I
> > checked the performance on an OM-1. Deteriorated in an instant! Awful
> > performance, just by changing lens serial numbers, or camera bodies, or
> > locking up a mirror ~ or NOT locking up the mirror!
> >
> > In other words, the results of any given test are good under those specific
> > conditions ONLY. Put the same lens on YOUR camera, and all bets are off.
> > Might be just fine for you, or bear no resemblance to anyone else's testing
> > results.
> >
> > Finding the "truth" about lens performance is a study in frustration...
> > <wry
> > smile>
> >
> > keith whaley
> >
> > ==============================================
> > List usage info: http://www.zuikoholic.com
> > List nannies: olympusadmin@xxxxxxxxxx
> > ==============================================
> >
> >
>
>
> ==============================================
> List usage info: http://www.zuikoholic.com
> List nannies: olympusadmin@xxxxxxxxxx
> ==============================================
>
==============================================
List usage info: http://www.zuikoholic.com
List nannies: olympusadmin@xxxxxxxxxx
==============================================
|