No expert Graham but i am assuming no tripod as kids and other people about. trucks not too near for H & S of yourselves so 70-300 Tamron but prepare to step up ISO for shutter speed handheld. Rule of thumb no VR is focal length = shutter speed required hand held so 300mm = 1/300th i would set camera to Shutter Priority, then dial in the ISO until you get the camera settings and f stop you require. Bear in mind to freeze very quick action around 1/1250th or higher required which is why these people who do motorsport photography have £5k lenses to give performance required.

Would take the 28-105 as thats got a useful range if you get any close up chances say walking about before or after.

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