On 11/12/2012 12:08 AM, List, OM wrote:
> Some of the tests I saw for the 75-150 M.Zuiko showed pretty severe shake.
> I suspect the optics in the relatively loose, long telescoping AF zooms can
> move.
Hmmm ... I hadn't thought that my 75-300 M.Zuiko felt loose in use. I just
pulled my lenses out. The 40-150, although
light, has no play at full zoom. The 75-300 does have a small amount, when
worked with my hands, but no more than a
couple of longish, heavy, all metal zooms from the old, MF days, that I grabbed
off the shelf.
I certainly can't see where it would have anything to do with motion blur.
My personal experience so far suggests that it is in no small part an issue of
technique. In the old, 35 mm film days,
my 150-500 mm zoom was a huge, heavy thing I only ever used on a tripod. The
Sigma 600/8 is much smaller and lighter,
but still, I'm not sure I ever hand held it. Even on digital FF and APS-C, I
only used it on a tripod.
Now, the 75-300 is slimmer, only a small amount longer and noticeably lighter
than the 28-300 I'm used to using hand
held most of the time on Canon bodies. So I started to use it much the same
way. And you know, 600 eq. just isn't the same.
You'd think I'd have learned by now, 'cause when I started using the Tammy lens
on the 60D (480 mm eq.) I started to
question whether something had started to go wrong with it. A little testing
showed that it was at least as sharp as the
non IS 28-300 that I first used on much lower resolution APS-C. The difference
was that it has IS, so I wasn't as
careful, counting on the IS to cover me. Sure, 16 MPs is tougher than 6, but
looking back at some shots on the 300D,
they were all it could resolve, and without motion blur, 'cause I really paid
attention to shutter speed.
There are factors that are just more troublesome at really long focal lengths.
DOF is really shallow, so placing focal
plane accurately is important. Subject movement one might not think of becomes
significant. Small details, like leaves,
become big enough that blurring from wind may show up.
Years ago, I was shooting Red Tail hawks in a nest across the street. With the
1000/11 Meade 'scope, I could get
visually close. But the nest was up quite high in a tree, and even a modest
breeze moved it noticeably through the
viewfinder. With modest (compared to contemporary digital) film speed and slow
lens, getting a shot that didn't have
obvious motion blur was a matter of timing, waiting for minimal movement, or
shooting at one end of the movement.
And maybe IS just doesn't give quite the edge at really long focal lengths.
Hard to tell, what with all the other
factors, but I'm starting to think it really only offers 1-2 stops of
improvement, not the 3-4 with shorter focal lengths.
That's only with Canon and the Tammy VC version of IS and the E-M5 IBIS. Can't
speak to other systems.
Moose In Motion
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What if the Hokey Pokey *IS* what it's all about?
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