I've recently acquired a p35-100 and immediately fell in love with the versatility and quality of the lens. It made me reconsider looking at the p12-35 or o12-40. Initially I thought they would not be bright enough however I found in general sharper lenses seem to do much better at higher isos. For example the o17 which I own looks terrible a iso3200+ while my p25 looks decent all the way up to iso 5000 sometimes 6400 stopped down to F2.0-2.8. Bottom line is I'm ready to put the o12-40 in the line up but 'should' get rid of 3 of my lenses (fighting hard to just unload 2, need to save money for something personal). Anyhow here's my lens lineup: o12-50 o17 p20 p25 o45 Of the list above by far I use the p25 the most. However I'm beginning to learn it's too soft for my liking at 1.4 and often find it best at f2 and up which makes it 1 stop off from the o12-40. I get my favorite images from the o45 but rarely use it. It's used for formal portraits or times I need a bit of reach but constantly find myself missing shots needing to go wide. For sure I'm going to sell the o12-50. My favorite lens in regard to focal length and character is the p20 but shooting my 4 year old son and having an olympus body the focus is too slow so I rarely put it on the camera anymore =(. The o17 sees a lot more time on my camera but I very much notice the lack of sharpness in comparison to my other primes and suspect the 12-40 will out resolve it. Even so the o17 finds a lot of time on my camera because it's a 'safe' focal length for me (easy enough to walk zoom and not hit a wall as much as I do with the 25) and I find the o17 focuses the best in video with my e-m5. So far I'm thinking to keep the p25 and o45 because they're more specialized and contrast the o12-40 the most in regards to producing shallower dof and the p25 for optimizing iso / shutter for VERY low light times. But then I'd miss the versatility and usefulness of the o17 and p20 (this would be easy of the olympus focused faster with the p20). What would you guys do or have done? Of those with the 12-40 are you guys finding it fast enough indoors? I often have to push shutter to 1/125th to 1/200th to catch my son who even when I say "cheese" or "look at the camera" he's bouncing. I do use flash on occasion and generally don't like the artificial look of shots with flash and find it distracting with my style shooting (i like candids and shoot burst or many shots at a time and don't want to blind people =p) and know I need to learn more in that regard (not looking for that suggestion =).