Sigma 120-300mm f2.8


Senior Member
Thoughts on perhaps this (already have a 2x TC i can slap on) vs 150-600? And which version are we discussing here?


Senior Member

we're talking about the newest, Sports, version in combination with the D750. Before purchasing the Sigma, I owned the first generation Tamron 150-600mm. I sold it, to help fund the Sigma...
I found that I used the Tamron mainly at the long end and that long end required quite some light...The same is true for the Sigma, but I get to use it at 300/2.8 and 420/4 as well. When it comes to comparing image's what I've found:

As the bare lens, the Sigma is sharp wide open across all focal need to stop down due to sharpness issues. This is a 100% crop at 300/2.8:

Using the 1.4X TC and the longest focal length gives you 420mm/f4. This setting is perfectly usable but I recommend stopping down to f4.5 (it gets better).

At 600mm, it starts to show a bit of weakness wide's a chart test I made (WB is off, but it shows how sharpness goes). These are 100% crops:

As you can see it needs f7.1 or f8 to sharpen up nicely...but that was the case with my Tamron as well. Here are two real world shots at 5.6 and f8 so you can gauge the difference:

At f5.6:

At f8: