I've tried many different setups over the years for track and field. While the 150-600 offers great distance, the loss of light is a significant risk in professional settings. Constant aperture is something i prioritize for reliability above all else. In my experience, the Tamron SP 70-200mm f/2.8 Di VC USD G2 has been the most consistent workhorse for sideline work. Technical performance of the focus tracking is snappy enough for high-speed action. Honestly, i prefer the build quality on the G2 series because it feels robust enough to handle the rigors of a stadium environment. That f/2.8 aperture is non-negotiable for evening games or indoor venues. You can usually find the G2 for around $1,200. If you have moved to a mirrorless system, the Tamron 70-180mm f/2.8 Di III VXD provides a similar technical advantage in a more compact form factor.

Building on the earlier suggestion, ive been shooting with this brand for a decade and honestly im super satisfied with how their glass holds up. It works well for my workflow and i really have no complaints about the optics vs the native lenses i used to lug around. But i think we might be skipping a step here. Before you pull the trigger like Hex mentioned, i have a couple questions to narrow it down:

• Are you shooting indoor stuff like basketball or outdoor field sports like soccer?
• What camera body are you using... mirrorless or a DSLR? That stuff really changes which way i would point you since the AF tech behaves differently across the generations.

100% agree

Honestly i have been looking for the same answer for months and its so frustrating that there isnt a clear winner. I'm usually very satisfied with my gear and have no complaints because the reliability is always solid, but i am just as stuck as you are right now. Still havent been able to pull the trigger on anything even tho i usually love how their stuff works well... been dealing with this for a long time and still nothing.

Yep, this is the way

Tamron 150-600