I use the 50-500 on a 50D. While it's not full frame, I've 30,000+ frames experience using it. The one thing I don't worry about is build quality! It's a substantial lens and built to last. While the coating on the tripod mount will lose it's paint after a while, the main body of the lens has coped with everything I've thrown at it over the last 7 years. I've had a couple of issues mechanically with it, the auto focus motor (needed replacing) and aperture blades (seized), but overall, it's the only lens on the market that covers my needs. About half the photos I have on here were taken with it. It's a great lens for the money and you rarely need to swap lenses during a session.
Equipment: 2x Canon EOS 50D; Sigma 10-20 EX DC HSM, 50-500 EX APO DG, Canon 24-105 f/4 L, Speedlite 430EX
ThierryD From Luxembourg, joined Dec 2005, 2054 posts, RR: 52 Reply 6, posted (9 months 1 day 17 hours ago) and read 3736 times:
AIRLINERS.NET CREW PHOTO SCREENER
as Tony pointed out I'm using the Sigma 50-500mm on a D700 and have been using this combination for nearly 4 years now. I've the old version of the lens though, not the OS one.
Image quality of this lens is perfectly fine over the whole zoom range, it's sharp and the autofocus works well and fast.
Don't have any issues with the quality in the corners; the only thing that you'll have to take care of is vignetting.
The only thing the lens is bad at is low light conditions; it then is very unreliable when focusing.
Never had any troubles with the build quality either; in all I've been using that lens for almost 8 years now and it still hasn't seen a repair shop.
For me the Bigma remains the best lens when it comes to price/quality relation.