Originally posted by swanlefitte If you are posting pictures close to infinity please say what you are doing. I expect on tripod to be good but hand held? If handheld what shutter speed? Are you posting this is as good as it gets? or just that you can get this good. Tell us about your failures as well. Was this a one off or a cherry pick out of 2000? We know this lens can take great shots, what we need to know is where that stops or when skill takes over or where it just won't work.
For my part, I'm fairly selective about the photos that I post on Flickr and link to here. In other words, unless I post something specifically to show a limitation or frustration, the only inference to draw from my images is that these are in the better class of images that I can get with this lens.
As a general observation, I'd say that I haven't yet got any really good bird images (with good feather detail, etc, like I could get with my FA*300 f4.5) at 300mm with the PLM where the bird is more than say 10 metres away. The images I'm getting have about the same resolution as my DA-L 55-300 at 300mm. At close range (say up to 5 metres) the PLM does very well (as does the DA-L, although the PLM renders better). I can't yet say for sure that the limitation lies with the lens rather than with me - I suspect that it is both. I would need to use a tripod more to make that analysis, but I just find a tripod impractical for the sort of wildlife shooting I am doing.
To illustrate, here are some images of a Black-shouldered Kite. (Both 1/640th; the first is f7.1, the second f8; both low ISO. Both shot in RAW, processed in DxO PL and cropped.) I'd guess that the bird was 10-12m away. The light was very good - a bright cloudy day. A white bird against a cloudy sky has its challenges, but the kite stayed obligingly for some minutes. I took maybe 15 -20 shots, standing, leaning on the car or leaning on the window. I focused and re-focused. I got as steady a position as I could. My usual approach with the DA-L 55-300 is to stick with f8 whenever possible, even at the cost of higher-than-ideal ISO. I tried that. I tried different shutter speeds. But I just couldn't get anything better than this. They are not terrible, but not of a standard that I would normally show. I've calibrated the AF, I've tried faster shutter speeds, but this is about all I can get so far at this distance.