Sigma 300mm Zoom v Prime

[Elevate29]

Hi there,
Although new to the forum, I've been shooting wildlife for a year or so now and want to upgrade to a faster lens. I already have the Canon 100-400 which is great but think I need something faster for the dull days! I'm only using a Canon 400D but plan to upgrade to a 40 or 50D soon.
I was thinking the Sigma 300mm 2.8 with a 1.4TC to be the answer but have heard and read that the 120-300 zoom may be sharper. Has anyone had experience with this? Obviously the zoom would be more versatile but as 300mm is too short I'd need to use a TC and wondered about its performance when used this way compared to the prime.
Any suggestions would be very welcome.

[tameblackbirds]

hello welcome I can't help you as I only use a bridge camera I enjoy it but it is very limiting for certain shots. Surprised no one as answered your query yet don't give up though some one will answer I'm sure Even if it's the next day

[glsammy]

With Sigma lenses and this one in particular you get a large variation in quality. I had one for a week, it was hopeless.Couldn't focus correctly 75% of the time and when it did I wish it hadn't bothered!
Here's an example shot if you can stand to look at it..

Obviously faulty so I returned it.
According to the supplier, this lens wasn't faulty.
One on line lens hire site has published it's failure rate figures and the 120-300 is the worst performing lens they have with an 84% failure rate!
Having said all that, IF you get a good one and are gentle with it, no doubt it's capable of performing well, although two on line reviews I've read both said it struggled to focus accurately, especially with moving subjects.
There's little in it between the Sigma 300mm F2.8 and the zoom.

[JB9302]

I was looking for a Sigma 120-300 f2.8 in Jan canon fit , few on the ground s/h and about £1000 plus , saw a 300 f2.8 and after seeing some shots of its use with a TC went and bought it privately , got a bargain I thought for £700 .
Not had much time to use it though , its mounted on my 40D on the tripod at the back window hoping to catch something decent , as the weather improves I hope to get out with it .

Julian

[Elevate29]

thanks for the replies...
I was leaning toward the prime as I'm not sure the zoom can handle a TC. From what you say glsammy, sounds like quality control may be an issue with the zoom. I'll have to think on... although £700 for the 300 prime sounds like a bargain JB! Be interested to hear what you think of it.

[lost in the woods]

Hi
I've got the sigma 300mm 2.8 ex prime with 1.4 & 2X convertors i have had no problems with mine. being a semi pro photographer they have had plenty of abuse over the last few years the only bit on lens i think is suspect is the auto focus to manual switch if that got a bit of a Knock. photo quality is high at 2.8 even with 1.4 fitted giving you a f4 420mm. You need to step the lens down to f8 if using 2x to get the best out of it. i very rarely use 2x as i have canon 600mm f4 i.s lens.
If buying try to test lens before parting with your cash i always do.Sigma , Canon & Nikon to name but a few have all produced lenses that vary and some need recalibrating to get the best out of them
Regards
LOST IN THE WOODS