ISOs outside the optimal range for a camera reduce dynamic range just like ISOs that are too high.
Ah right. This was more of a wishlist type thing. I'm not actually sure of the engineering required to accomplish a digital ND filter. A physical one(s) would be fine too.
Small lens don't correspond to a lack of DoF.
Correct. Small aperture does.
DoF can be squeezed out of many compact cameras. If I can do it with a 1/2.5' sensor with a f/2.8 max aperture, then it's absolutely possible with a 1/1.7' sensor with a f/1.8 max aperture. The only string attached is that the DoF is most obvious in macro shots.
As for portraits, there isn't much DoF at all. Better off adding a Gaussian blur to the background than trying to get some.
Sorry, I wasn't clear in my wording. To clarify, there is little control over shallow DoF effect at non-macro focussing distances. This has to do with the physical size of the aperture compared to the subject, the distance to the background/foreground, and the relative size of circles of confusion that causes the blur compared to the size of the features of the subject. I stand by my original assessment that like all compact small lens/sensor cameras, there is no usable shallow DoF for "normal" subjects. Macro is a whole other thing, it worked fine in your sample shots and the dragonfly image I posted. It is not sufficient for portraiture, which I think is something a lot of people would like to do, and they think that it can magically be done because the EX1 has an f1.8 lens vs. the typical f2.8-3.5 lens of most P&S cameras. This is not the case. The difference between f1.8 and f2.8-3.5 in real size on a P&S camera is just not enough to achieve good out-of-focus blur for portrait work.
You can think of it like this: when focussing on something in the foreground, the maximum size of an out-of-focus point light source in the background is directly proportional to the aperture size. If your subject is small (aka macro photography) relative to the size of your lens/aperture, then a small circle of confusion in the background is relatively large and you get good subject/ground separation. If your subject is large (aka portraiture) relative to the size of your lens/aperture, then a small circle of confusion in the background/foreground is relatively small, and seems not blurry enough to generate good subject/ground separation. For this you need a lens/aperture that is scaled up to better match the size of the subject and distance between subject and foreground/background.
Hope that makes sense.
Also gaussian blur is insufficient for any number of reasons including it not actually being an optical effect resulting in pleasing bokeh (a point light source optically blurred due to out-of-focus will render as a large well-defined disk, a point light source gaussian blurred will end up as a smudge), and most importantly not being able to generate subject/ground separation in which the subject has a crisp in-focus edge directly bounding on an out-of-focus foreground/background element. There is a reason why we don't do
everything in software yet, and people still are after this in their lens system. The reason why your leaf photo works is that the edge of the leaf is sharp directly against the blurry background. If you have the ability and patience to photoshop cut elements of your photos out and blur different depths at different amounts, go for it =) I would rather get the lens to do that for me.
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