Someone in another place mentioned that there isn't a huge amount written about this interesting lens. There are a couple of well-written reviews, and scattered posts on various forums about it, but in the spirit of "more information is better", I'll lay down some of my thoughts about it.
It's compact for it's focal length - a key criteria for me when I purchased it. I already have a 70-200L/4, but it's too long to carry with me everywhere. The 70-300 goes with me literally everwhere.
It's not L-quality, but neither does it bear the hallmarks of a cheap 'n' nasty lens (and it shouldn't, given its price!). A tad soft, a tad lower in contrast, and, occasionally, some odd bokeh (depending on the background). I can live with these, and felt I was paying the premium for the benefit of a compact long lens.
It's a bit expensive for a non-L lens.
Image Stabilization is great, and it's fast-focusing.
It works with 3rd-party TC's - I bought a Kenko 1.5x TC especially to use with this lens, kind of as an experiment. It does work, and I've actually managed to grab some
reasonable shots with that combo.
For me, this lens was a no-brainer, because I travel a lot. In fact, even when I don't travel, I still appreciate having it, because now I can carry a long lens with me everywhere, as it fits in the bag so nicely.
I have many sample shots available for viewing on my website, starting with the
"Borneo/Sarawak" (2005) gallery, a few at the
"Sauris (2005) gallery", and with scattered examples in the
"Weekly Photograph (2005)" section, commencing from May 2005 when I bought the lens. My personal verdict is that this is a fine lens for casual use, especially in urban and/or travelling situations. I'm no wildlife photographer, but I'm pretty sure that it would
not deliver what a wildlife photographer needs (reach + speed).
