1) Neither shallow or deep DOF is better than the other they are
merely techniques at our disposal to use as we see fit.
Agree.
2) Clearly different format offer different possibilities, so for
most of us we need more than one camera and once again saying A is
better than B is pretty pointless.
You have to spell out "clearly". In what ways do different formats offer different possiblities? Many make it sound like larger formats are handicapped for deep DOF, and this is simply not so.
3) Many new photographers probably seek out the shallow DOF look to a
degree as they relate it to achieving pro-type photographic results,
to a degree this is a true reflection, however many pros shoot for
deep DOF too, it depends on the job, clearly portraits are generally
shallow DOF most of the time.
I seek it out because we see in three dimensions, yet photos are two dimensional. Shallow DOF goes a long way to giving a less 2D look.
4) It is actually very much harder to create really good compositions
with deep DOF as you have to pay far more attention to all the
elements in the photo. The shallow DOF has the effect of simplifying
the image which makes the message clearer and less distracted by
other elements which is often a really good thing.
That's also because while our eyes "see" in deep DOF, our brain "sees" in shallow DOF. That is, we usually focus on the subject in everyday sight and ignore all else, the same as we filter sound.
5) On professional shoots really shallow DOF is often a real problem
as there is very little sneeze room for focus inaccuracies and
subject movement, so often I would go for a little more DOF rather
than risk a shot that can't be sold because nothing ends up sharp.
That's why accurate focus is a must. It requires both skill and good equipment.
6) I personally would love to see more deep DOF portraits, many years
ago I produced such things professionally where the subject was part
of his environment and the two were actually important to the shot.
In the initial post in this thread, I asked if any had some to share. The only deep DOF people pics I see are studio portraits with a muslin background or UWA.
7) A lot of the really shallow DOF stuff we see is medium format,
which is great when you need that look but it was also very hard to
work with on the job compared to 35mm, no sneeze room and slow
shutter speeds if you really needed deep DOF. But the DOF look you
get with MF is to my eyes far better than that of FF digital or APS
type sensors.
Well, it's funny that you say that, because MF lenses are not as fast as 35mm FF lenses, and it enjoys no advantage in terms of DOF for the most part.
8) I feel to an extent shallow DOF approaches at present are a bit of
an over- reaction to the deep DOF characteristic of the compact
cameras and as a result some of it is probably a bit overdone, the
nicest results I feel lie somewhere in the middle ground.
I, too, feel that most people "abuse" shallow DOF and use lower f-ratios only to use a lower ISO and get less noise.
9) To a degree the look of the DOF is effected by the lens clarity,
some lenses are so bittingly sharp where the image parts are in focus
that the out of focus areas look more out of focus than they really
are because the contrast between in focus and out of focus areas is
very pronounced. (I just love these lenses)
You'll have to show me examples of both sides of that coin.
10) The shallow DOF looks success' is very much dependent on the
final print size, if you are printing large then it can easily end up
looking way too soft, yet its fine in a Postcard or 5 by 7 print for
the desktop.
Well, I've printed f/1.2 pics at 20x30inches, and, quite honestly, they rock. My favorite print size is 12x18, and they look just as they do on my computer monitor at that size.
11) Noise is far more obvious on smooth toned shallow DOF areas so it
probably a good thing that compact don't do real shallow DOF so well,
but it also means high ISOs and shallow DOF on DSLRs are not that
clever either, though in practice it shouldn't be a problem as wide
apertures usually means less need for high ISOs.
Compacts
cannot even
approach the DOFs of FF. For example, f/2.8 on a Canon G9 corresponds to f/13 on 35mm FF. Secondly, I've printed virtually noisless ISO 3200 pics at 12x18, in particular, the ice cream pic here:
http://forums.dpreview.com/forums/read.asp?forum=1032&message=25513052
12) A strange little anomaly is the the as we go larger in print size
the DSLR may actually be at a disadvantage to the compact for deep
FOF shots given reasonable viewing distances, this is because the
regardless of the aperture the actual DOF is still not as great as
the compact so when you enlarge right up the out of DOF areas become
more obviously not quite in focus and this is accentuated because the
in focus areas are proportionally sharper. Of course the compact has
more noise....but then from 3 feet or more its not actually visable
and the image has roughly the same sharpness across the whole image
depth. I know that will cause some eyebrow raising but I promise I
have lots of exhibition prints from the two formats that demonstrate
this.
The
only time larger formats are at a disadvantage for deeper DOFs is when they have to exceed their higher ISOs to maintain the DOF and shutter speed.
--
--joe
http://www.josephjamesphotography.com
http://www.pbase.com/joemama/ 
) and between 4/3 and ASP the difference is quite little judging by the photos (and the sensor size).