Sigma 150-600 Sport

[Kayaker72]

Ok. So I have to decide if I am keeping the 150-600S. Before seeing Bryan's results of the 100-400 II + 1.4TC, I had essentially decided to keep it. But the results at f/8 for the 100-400 II @ 560 mm were better than I had expected.

My situation: I am finding I am still cropping 600 mm shots and as much reach as possible is my primary intent. So what I am looking for is the best ability to capture high quality images at as long of focal lengths as possible for around $2k (I won't know my actual budget until tax returns, but I usually can get $2k).

I've been pleased with the IQ and AF of the Sigma. I didn't post them, but it did track well in a few BIF situations.

As I see it:
Sigma 150-600S
Pros:

• Native 600 mm
• Within budget
• Good IQ
• Good AF
• Good reviews thus far (lenstip, photoblog, cameralabs, etc)
• 2/3 stop at 600 mm
• Reports of Sigma AFing with 1.4xTC giving a 840 f/9 lens.

Cons:

• Size/weight
• Long term concerns about 3rd party lenses/AF

100-400 II plus 1.4xTC
Pros

• Size/weight
• IS
• MFD
• "Canon" AF/Quality
• 77 mm thread size
• White with red ring just looks good
• Already seeing images like this.

Cons

• $~700 more expensive (lens plus extender)
• AF speed with extender???
• AF at f/8 on 5D3 limited
• Overlap in range with my existing kit (70-200 II)
• Not sure, but IQ at 560mm??

I should emphasize, I am willing to put up with size weight issues to "get the shot"

Thanks
Brant