Review on Sigma 50-500mm f/4.5-6.3 APO DG OS HSM SLD Lens for Canon DSLR Camera - Ultimate Ultra Telephoto Zoom Lens by Mike Fedd

Very Versatile Lens - Period! {Pros: - Huge range - Huge versatility - Very sharp for an ultra telephoto lens (I have this lens and a Canon 100-400 and this lens was just as sharp if not sharper than the 100-400) - Optical stabilization is really good - very good job - and especially appreciated with such a heavy lens - shoots good portraits straight out of camera with good colour, contrast and sharpness - although a little speed up in Photoshop really helps - but doesn't need much - great for nature photography - does quite a bit Pretty cool moon shots with pretty good detail - comes with a tripod collar which the Canon lens doesn't have. (I use a lanyard to carry my lens and camera - the UI turns the lanyard up, and I carry my camera like a briefcase with a handle - it makes it a lot easier to carry this beast with a lens. Close focus - good for close-ups {Weaknesses:- Difficult when handheld all day - the autofocus hunts more than some of my other lenses and has a bit of an issue capturing smaller subjects like birds or low-contrast subjects - especially when trying to focus on a bird in flight against a clear sky - although I'm only using spot metering, which may be one of the reasons - the telephoto lens detaches after a while, causing the lens to snap open when not locked and tilted down becomes, or slams when tilted up was a problem with the lens causing "Error 99" (can't remember error code # now), a When I had to remove the lens from my Canon 7d, and then reinstall the lens to get it working again - sent it and it took almost 3 months to get the lens back from Sigma which I thought was very excessive - also there was absolutely no message from Sigma letting me know of any problems or progress with the lens while it was in the shop - it would be ice to even know how they handle the lens as it has taken so long. However, the lens hasn't caused the error again so far, however I haven't used the lens much either as I've been concentrating on street photography and macro photography lately, but I will be using this lens again for wildlife photography this winter. Snomobile racing etc. Let's see if this problem comes up again or not - f4.5 is a pretty wide aperture for the lower end of the range - you need pretty good light to use this lens - or a good camera with good ISO -Skills - my Canon 7d I can't seem to get past 800 as there is too much noise, that's when it comes into play. Overall I'm very happy with this lens, despite the flaws, it's a very versatile lens with a tremendous range, especially on a crop camera like the Canon 7d - the long end is around 800mm - and that allows you to to really reach out and photograph these warlike beasts that were always out of reach with other subjects tivas.