This is a pretty good example of a picture that I want to be able to take at music festivals. It's not a head shot style portrait. Perhaps it's wide enough to be called an "environmental portrait." It gives some context to the subject. However, I really want to be able to separate the subject from background with shallow depth of field.
It is a matter of physics that Micro 4/3 lenses will have more depth of field at a given field of view, because of the crop factor and sensor size. That is, in the shot above, which was shot at 35mm focal length on Micro 4/3, has the same field of view as a 75mm lens on a full frame 35mm sensor. The Micro 4/3 lens has more depth of field in this shot than if I had shot it with a 75mm on full frame at the same f-stop (f3.2 in this case). All this adds up to less ability to separate your subject from the background with the Micro 4/3 format at a given field of view and aperture.
While I like this shot very much, I would prefer to have the background blurred more. Yes, I should have shot it at f2.8, which would have narrowed the field of view a little more, but that's only a half-stop wider, and would not have made much difference.
So, my preliminary conclusion is that no, this is not the perfect lens for these types of shots. I could have done better with one of my prime lenses - either getting closer with the Summilux 25mm f1.4 or using the Pana-Leica 45mm f2.8 Macro-Elmarit. Actually, the 45mm f2.8 may have been about the same, since I would have had to move away from the subject, which increases depth of field. The true best would be an Olympus lens - either the 45mm f1.8 (which would have been perfect for this shot), or the 75mm f1.8, which would have required me to be further away. I don't own either of the Olympus lenses, yet. The 75mm is on order.
I must say that I've enjoyed using the new Lumix 12-35mm f2.8 lens this weekend. However, I am close to concluding that I prefer to shoot primes. I've been very careful with this lens over the past couple of days. I have in my mind that it may go back for a refund. I haven't decided yet, and need to look at more results.
Don't get me wrong. It's a very capable lens. I just think I prefer primes.