40D vs 30D?

The 40D is better but not by much and most won't notice unless they 'peep. It is just nicer to use and it does seem to be a tad cleaner at 800 and over ISO, but I hardly ever use that so not a big deal. Build is up a notch on the 30D too, even the buttons I own both. The 5D is better than either by a good margin IMO. I owned one.

Helrain wrote in post #4171803
I also don't like the way they implemented AF on the 40D Live View - but I guessed it was due to technical constraints?

With the mirror (and submirror) lifted so the sensor can see the lens, the usual autofocus sensor gets no light.

-js

lol yes but this " contrast based " autofocus seems to me, i'd like some tests on this to find out if it's really ment to be trusted... honestly the mirror down / up seems trusty n cool, but i'd love to have both.

but again if nikon has reaaallly made good stuff here, then .

From a Nikon Press Release:

"What makes Nikon's Live View mode so uniquely effective are the two options it provides for autofocus operation.

The first mode is the one used by everyone else.
Because the traditional AF sensors are blocked when you flip up the mirror for Live View mode, you have to drop the mirror to focus, then flip it back for Live View.
Canon, Nikon, and Olympus all have this mode.

The real trick comes in Nikon's second Live View (Tripod Mode) autofocus option.

In this mode, the camera performs contrast-detect autofocus, just like any point & shoot digicam.

That is, it reads data off the CMOS image sensor and evaluates how abruptly light to dark (or dark to light) transitions happen on the image plane.

Contrast-detect AF isn't nearly as fast as phase-detect, which is why the shutter response of most digicams is so much slower than that of most DSLRs, but the camera can focus without interrupting the Live View display.

As an added benefit, because it's working with data coming from the main image sensor, you can move the AF point anywhere you want within the frame area, right out to the extreme edges."

The discussion about AF with live view is interesting. As I mostly / only use live view for manual focus (macro, stills and landscape), I wonder under what circumstances people use it with AF. Yes, I know it's built in that you CAN use live view with AF, but I'm unclear as to when you'd want to use it this way in normal shots?

I'm not trying to imply that one shouldn't use AF and live view, either - just curious...

I can't see myself using live view for fast paced stuff like sports. But i do understand for Macro and maybe portrait work to give you a good look at the focus. but then again the LCD brightness doesn't giveu the best preview of the true color and look of an image

I used live view for some outdoor baby portraits this weekend. Since I had to get the camera down to ground level, and the ground was soft, I just used it to get the composition, stopped down a bit, and used the AF. There is no real way I could have gotten what I was going for otherwise without laying flat on the ground.

Just to be clear about the 40D...

30D: good.

40D: better.

Everywhere - handling, AF, noise, "added value" functions...

And so on.

never have any complain with the 30D 's Image quality, and 40D just better and less touch up require.