The Long Lenses (300/400/600) all require firm control when shooting at distance, any movement is going to throw off the focus, an earlier mention of shooting in AI Servo is good advice that I have learnt through many OOF shots when shooting in Single Shot, an error I used to make (Compliments of the centre spot focus point on the 5DMK2), has been with the advent of the 5DMK3 & 1Dx, getting out of the habit of using the Centre Focus Point & recomposing (sure fire method for OOF shots), getting used to the diversity of 61 Focus Points after the single usable (IMO) focus point of the 5DMK2 has been a real learning curve, enjoyable though & productive. To answer an earlier question on using a Monopod when shooting at say 1/1600, perhaps not usually, but the weight in the 300 V1 is still a factor & I would suggest unless your Arnold, you may find a support system a real advantage. When shooting Wildlife on Safari I always use the RRS Safari Rig Monopod, swear by this system, these guys make absolutely the best gear available when it comes to Camera support.