A great versatile lens with superb definition.

I've had this for a few months and use it on EM1Mii. Terrific for sport, great definition and contrast. Since I changed to Olympus I've used by big Canon stuff (1Dx plus 300 f2.8, 70-200 f2.8 etc) very little.
I've used it as well with the 1.4 converter and if there's any degradation, you'd have to look very hard to see it.

The 40-150 is a formidable lens, very sharp even with the TC, but the out of focus areas that would show detail if they were in focus can look pretty ugly. This is not uncommon in zoom lenses, but it is worth mentioning so people do not think that this lens could replace f/2.8 fixed focal lenses in the 40 to 150mm range.

Paul De Bra wrote:

The 40-150 is a formidable lens, very sharp even with the TC, but the out of focus areas that would show detail if they were in focus can look pretty ugly. This is not uncommon in zoom lenses, but it is worth mentioning so people do not think that this lens could replace f/2.8 fixed focal lenses in the 40 to 150mm range.

This is true. One way you can get over it if you're specifically looking for nice bokeh is to get in closer so the background is really OOF.
I've a Canon 300mm f2.8 L IS. Fab lens but the OOF areas aren't as nice in my previous 300mm Sigma f2.8, which wasn't as sharp as the Canon, but had gorgeous bokeh.

This one which I shot yesterday, shows BG really OOF and it's fine.

This one shows what I call choppy bokeh and that isn't nice.

I have not found the bokeh to be an issue, for me at least, when using this lens - particularly for outdoor portraits.

Not perfect, but I would not say ugly either.

Even when the OOF part is the 'subject' of the photo:

or, when the background is quite close:

Of course, I am sure some folks, with more exacting standards than myself, may disagree, but for my use, I like this lens just fine!

Take your second photo. The people and building in the background are silky smooth because they are way way way out of focus. But then look (at 100%) at the foreground. The branches that are not nicely in focus show a double-edge effect. That is the weak point of this lens. It is not a big issue, but it's there.

This is getting down to the point of nitpicking. Sharpness and contrast at the fast apertures of this zoom are more important. Bokeh in these shots look fine. I can't see anyone getting too uptight about the slightly OOF parts of the image. "Oh look at the branch. Shot ruined!" This bokeh stuff is a jokeh.

Bokeh is nice when it's brilliant, but it's not everything. If it'll do, it's good enough!

Of course my comments can be considered nitpicking. Everything else about this lens is just fantastic. I like it a lot and I do consider it worth the money (not in absolute terms but relative to other lenses).

Some people just always look for perfection (I am one of them, but not so much in terms of my pictures, not at all in fact) and if there is a flaw to be found they will find it. That's what my bokeh comment was all about. It has actually never really bothered me.

Paul De Bra wrote:

Of course my comments can be considered nitpicking. Everything else about this lens is just fantastic. I like it a lot and I do consider it worth the money (not in absolute terms but relative to other lenses).

Some people just always look for perfection (I am one of them, but not so much in terms of my pictures, not at all in fact) and if there is a flaw to be found they will find it. That's what my bokeh comment was all about. It has actually never really bothered me.

I agree Paul, and, as I said, it's not perfect but it meets my standards.

I do rate this as one of the finest lenses I have used, taking its optical qualities and versatility into account.

The 75 has a special place in my system and when it finds itself in the right scenario, it is truly brilliant but, for all round use for me, the 40-150 2.8 has it.

Now, where Olympus to release an upgrade to this lens, I would be very tempted indeed!