I used the late model 135 f/3.4 on my M8 last weekend with a 49mm B+W 486 UV/IR cut filter, indoors under tungsten light, mixed tungsten and daylight through a window, and also a few shots with a tiny flash, and the results in all cases were spectacular. These were all handheld head shot portraits from across a room of my wife (she declined to let me post some images...sorry). All of the shots were wide open except with the flash. I also tried he 90 f/2 ASPH APO, which performed beautifully as well, but the added distance I was able to shoot at with the 135 caused me to use it more than the 90. I mostly shot at 1250 but some at 640 in both cases with exp comp at about -1.5 as the M8's 1250 is really 1600. I used the 1.25x ocular in about half of the shots and I can't really say that the results were that much better, but I was taking my time to focus, was seated and stable and my wife stayed fairly still, so the focus wasn't going in and out as it can do with a long lens in that situation. Framing was a breeze. I just estimated that the shot would be about twice the width and height of the focus patch, figuring that this would give me some leeway. I checked the LCD to make sure I was getting what I wanted and then reframed if necessary, and then shot away. The bottom line is that this is a terrific lens on the M8 if you can take your time, but that should always be the case anyway, IMO, when shooting wide open with a lens that has an effective 180mm frame. I don't know if the 135 f/2.8 with eyes would have been better, but I frankly doubt it. I wanted to see if the 135 f/3.4 would work for me before looking for a clean 135 f/2.8, but that is not something I intend to do now. Of course, the lens is a little long, but it is not that thick and, for me, was as easy to use as the 90 f/2 but produced much tighter portraits. By the way, be careful with this lens photographing someone who is in denial about his/her age as it is super sharp corner to corner and shows everything. Fortunately, my lovely wife, at 64, is quite comfortable with her age and occasionally indulges my need to make head shots to test my lenses. She is just a little shy about me posting shots of her, so I mostly don't.