It looks like we’re done with megapixels, thank goodness we forgot about metering, and there really isn’t much more to say about white balance and ISO ranges… so why is autofocus such a thing?
Probably because it’s an area where manufacturers are still making technological advances that can help boost sales of new cameras, and can talk about the technological wizardry of AI and deep learning as if we’re on the cusp of a new age of digital imaging would stand. Which is a bit annoying for those of us who aren’t quite done with the old one.
The latest and greatest in professional cameras (opens in new tab) are packed with new autofocus features, new subjects and new algorithms with each release. But do we need them?
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Do you need AF for videos?
Of course you do (we hear you say). How else can you keep your subject in focus – especially when you are the subject? It’s true. If you’re a solo shooter, constantly on the go, and often presenting right in front of the camera, you won’t be able to focus at the same time. With AI-powered people and object detection, real-time Eye AF, and subject tracking, you can film in a way you’ve never done before. The Sony A7R V (opens in new tab) even has its own AI processing unit.
But not everyone is a vlogger. Surprising, right?
In fact, much of commercial, broadcast, and especially cinema work is staged with fixed actor and prop positions and carefully planned camera movements and focus transitions, usually with a human or mechanical focus puller.
Here the autofocus is not only unnecessary, it would also be annoying. What you definitely don’t need in a professional shoot is a set of algorithms that figure out what to focus on for themselves. For anyone choosing the best cinema camera, autofocus is probably the last thing on their mind.
Solo shooters and vloggers also use manual focus from time to time. That’s why lenses still have focus rings, why cine lenses have serrated control rings, and why people make follow focus controllers for gimbals and rigs.
With video, focusing is something many operators definitely do themselves. Does this also apply to still images?
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Did the AF destroy the depth of field control?
depth of field (opens in new tab), and the ability to control it has pretty much gone out of fashion in the still photography world. These days we’re in love with fast apertures, background blur, and depth of field narrower than a mosquito’s eyelash (whether they have it, I don’t know). Ultra-fast lenses are a novelty (and a bloody expensive one) that show no signs of wear. The best lenses for bokeh will turn anyone into an artist (or the same artist) and the right AF system will do all the hard focusing work for you.
But not so long ago, the photography world was obsessed with depth of field (opens in new tab)and how to get more done with smaller apertures and carefully chosen focus points that only you – not the camera – can figure out.
The whole art of depth of field control is not just knowing what aperture to use, but where to focus – BETWEEN the closest and farthest points of interest in the frame.
Even the savviest AF systems can only focus on one thing at a time, and none of them understand middle focus points. Well, actually Canon’s A-DEP mode worked on their DSLRs a few years ago, but they soon discontinued that.
The autofocus, including the latest AI Subject Recognition AF, is very good at focusing on one thing at a time, but is utterly inadequate for situations where there might be two.
AI autofocus – when an assistant becomes a know-it-all
Autofocus, like any automated system, is great when you don’t have the time or inclination to do a job that a machine can do just as well. But very often it’s not as good at it as you are and you end up with a worse or less predictable result – but hey, at least it was easy, wasn’t it?
Of course, we can ultimately be convinced that AI can figure out our intentions just as effectively as we can, or that it’s so much easier to let a machine do our thinking that we should stop trying ourselves. Won’t that be great? Or has that already happened?