«

On Thursday, March 31, 2011 7:11:29 PM UTC-5, Bruce wrote:
> David Dyer-Bennet <illeg...@gmail.com> wrote:
> >On Thursday, March 31, 2011 12:07:42 PM UTC-5, Rich wrote:
> >> On Mar 31, 6:00�am, Bruce <docn...@gmail.com> wrote:
> >> > As you have just bought a D7000 instead of your first choice GH2, I
> >> > feel sure that these replies are exactly what you wanted to hear! �
> >
> >> Not really. If the GH2 wins (or maybe anyway) I'd just sell the D7000
> >> and get the GH2, like I originally planned. I have no brand loyalties..

> >You will have! After you've bought your first few thousands of
> >dollars of lenses . Well, perhaps not actual loyalties; but at
> >least strong reasons to want to stay within a lens family.

> > I do agree with the general analysis of the advantages and
> > disadvantages of those two types of cameras. For action, a good
> > DSLR is a big win over anything using contrast-detect auto-focus
> > off the main sensor.

> When it comes to single shot AF, the GH2 is as fast and accurate as
> any consumer-grade DSLR, and a lot faster than some. The Panasonic
> GH2 camera is a game changer, because it gives similar AF performance
> to some of the best DSLRs.
>
> That's a first for contrast-detect AF, but over the next couple of
> years the new technology will become much more widely available, and
> not just in the Panasonic range.

Improvements in that technology are always appreciated .

I don't know how much less good something like a D5000 is compared to
my D700, or how much better the GH2 is than a Panasonic LX3 or an
Olympus EPL2. But there's sure as heck a huge difference between the
D700 and the LX3. Like, the D700 focuses quickly and reliably by
bonfire light, whereas the LX3...doesn't.

I saw an article that somebody had integrated phase-detect sensors (or
at least one of them) onto a sensor chip, so they could offer
phase-detect AF at least at the center point of a mirrorless camera.
Not sure it has reached market anywhere yet, but that's another
interesting idea

> I am not prepared to make similar claims for the GH2's AF performance
> with moving subjects because tests tend to be more subjective and
> therefore less reliable. However, my subjective opinion is that it is
> no slouch.
>
> Also, don't forget that contrast-detect AF tends to be much more
> accurate than phase-detect AF because inaccuracies with front and back
> focus are eliminated.

Also any "alignment" issues; the data comes from the main sensor, so
whatever the software controlling focus sees there really IS what will
be recorded in the end. Whereas the extra mini-mirrors on the back of the
big mirror that direct the light to the phase-detect cells in a DSLR can
all be slightly not-quite-right which can result in focus errors.