Sigma70-200 f2.8 with 1.4 teleconverter - Thoughts?

[denno75uk]

I'm wanting a decent long lens for motorsport and nature photography. I understand that 200mm would not normally be considered long enough so thought that using a X1.4 converter would be a suitable solution.
I want a fast lens, but it must also be (relatively) affordable which is why I am thinking of the 70-200.

Does my solution of the 70-200/TC combo make sense based on my criteria?

I was also considering the Sigma 100-300 f4 as I've read reviews saying it's IQ is fantastic. Is it fast enough for my needs though? And if I consider f4 would I be better with the Canon 70-200 f4 L USM IS? I could buy a Canon TC at a later date.

I'm off to see the in-laws near the Pyrenees soon and am hoping to get the lens by then.

I know similar threads exist and trust me I've read most of them here and on other forums but this issue is consuming me at the moment. I'm dreaming lenses. It's also starting to really PO my wife and people at work as it's all I talk about and frankly, people are sick of hearing it so any help won't just be gratefully received, but may just stop me dying a lonely old man :cry: .

[Mr. Clean]

The 100-300 would have a tad more reach and a tad better IQ than the 70-200 plus a 1.4. The 70-200 is great wide open but images from the 100-300 look sharper wide open.

[Borderfox]

I think the 70-200 f2.8 with a TC will give you more flexibility, I have heard too that the 100-300 f4 is excellent. I was in the same pinch and ended up with the 70-200 and the 1.4xTC, I'm very happy with the pictures from it and still have a f2.8 at the end of the day..

[turbodude]

which 1.4x did you get?