This thread had me thinking about some real world shooting situations that would show up an significant deficiencies in an AF system. So I looked through my galleries to find some examples. I haven’t got access to the originals just now so these are all processed and cropped images from my online galley, but I think they are valid in the context of the desire to capture useable images of a moving subject.
This was one such challenging (in my view) situation where the cars were coming into view at rally speed between a stack of tyres and a fence in failing light, so it wasn’t possible to track the car as it comes into view, only anticipate the moment the front of the car would come into view, at which point the AF would need to acquire/lock and then track as the far came towards me. There was then a brief opportunity to grab a panning shot as the car passed before it would disappear out of view again. All from very close range. Yes, I could prefocus on the tyre stack but the camera still had to work to lock and track for the head on shot, then relock (it it had lost focus) and track for the panning phase after I’d stood up and spun round, and zoomed for the pan.
I had the K3 and DA*50-135 (that renowned lighting fast focuser
) shooting AF-C centre point, Tv , burst and RAW. I got plenty of keepers and really only felt limited by my ability to keep the cars in frame and desire to remain out kneeling in the cold and damp.
Two consecutive frames in under 1 sec.
55mm 1/80 f4.5 ISO 200
Time 16:29:02
Time 16:29:02
Followed by 3 unusable frames due to speed and accuracy of framing whilst transitioning from crouching to panning position
Final panning shot before car disappears.
Time 16:29:03
The other shots from this session are here
Snetterton Rally 2017 - Images | Simon Wood
This was another very similar situation but much less callenging due too the much better light and complete 180 degree view of the cars entering the stage, passing and leaving the stage, and I had a nice range of snacks and drinks with me to keep me going all day!
Same camera and lens combo shooting RAW again, but single shot mode. Whilst less challenging than the last situation, the brighter conditions did allow me to introduce the added complication of shooting at high shutter speed for the oncoming shot for a crisp image with the flying stones, before scrolling down the shutter speed for motion blur on the panning shot phase as the car passed. This is where the ergonomics of a camera probably become more important than the AF.
2 consecutive frames over 4 sec. period.
Time14:27:20
75mm 1/80 f11
Time 14:27:24
123mm 1/80 f11
Consecutive frames over 7 sec. period
Time 14:32:22
123mm 1/1000 f3.2
Time 14:32:23
123mm 1/1000 f3.2
Time 14:23:29
90mm 1/50 f14
Other images from this session are here
Classic 30 Rally September 2014 - Images | Simon Wood
In both situations I missed shots but was more than happy with the keeper rate given the conditions and I’m really not sure I would have been better off with any other system - maybe, maybe not.