[AQ]

I want a longer lens than by current 70-300 for birds and wildlife.
I am toying with the idea of getting the new sigma 150-500 zoom lens for my Canon 40D. One thing that worries me slightly is the aperture of f6.3 max at the 500 mm end. Is that going to be wide enough for the autofocus to work well. I see to remember reading somewhere that you need at least f5 to get a good af lock.

[stepheno]

Ok....give me a clue

[AQ]

Sorry you have lost me. What did I not make clear

[stepheno]

There's nothing there what colour font have you used?

[silkstone]

It looks fine using the nice blue theme.

I can't answer specifically about the Sigma 150-500, but the Tamron 18-200 is f/6.3 at 200mm and there is no problem at all with AF on the Canon 30D.

[Dabhand16]

I've seen several comments that say that the Bigma, which I think has the same aperture at the long end works OK, so if that is right, so should the 150-500.

I've also seen comments saying the Bigma is a better bet as it is lighter with no image stabilisation. You are not going to hand-hold a lens that weighs close to 2kg for long OS or not! Once you have it on a tripod/monopod, the OS is not so much of an advantage.

Try Googling Sigma xxx reviews and you will find lots of stuff out there.

[danpen]

The Bigma does a bit of tomfoolery with the aperture reported to the camera to make the autofocus work (which it does pretty well), I expect the 150-500mm does the same.

Graham, I'm no hunk but can happily hand-hold all 2.6kg of the 120-300mm f/2.8 for the duration of a football match and have done a few times. And that's when attached to a 5D with battery grip which adds a fair amount more. I think the Image Stabiliser would be useful if it's anywhere near as good as the one on my Canon 100-400mm but I don't know how good Sigma's OS system is.

I had a 50-500 for a while and find the 100-400 much more practical partly becuase the IS means you can get away without a tripod.

cheers

Dan

[Dabhand16]

Thanks for that Dan - interesting. I appreciate that a well balanced kit will be much easier to hump about, from what you say it is probably not worth worrying about.

I think that the two new Sigma long zooms will attract a lot of interest, especially if the weight is not too much of an issue.

[danpen]

The balance does help, and while I am happy to stand around with it at an event where I know it'll be useful, I'd be very unlikely to take it on a walk on the off-chance I might want it.


cheers

Dan

[AQ]

Originally Posted by stepheno

There's nothing there what colour font have you used?

Ah I see your problem. You are using the black forum colour I assume, I use the blue one. I posted the original from work. (well it occupies the time) using IE 6 with no spell checker. As I do not spell that well I typed it in Word with a black font and cut and pasted it into the forum. To me it looks OK but when i switch to the black Pixalo theme the text vanishes.

[Chris H]

Yup another dark theme user here, easier on my eyes but ye canny read black LOL

[Sonsey]

Anthraquinone - I've edited your original post to change the text colour back to normal so everyone can read it easily, hope you don't mind.