I see the AF/MF clutch as a negative...too easy to deploy accidentally. It's not a deal killer but it adds unnecessary mechanical complexity and I would rather not have it on any lens.
I switch from AF to MF with a quick button press (red record button.) IMO, the MF Clutch would be less convenient for me.
Switching between AF and MF is not the reason to have the MF clutch. because THAT can indeed easily be done with a button - and much cheaper.
In fact, you do not even have to assign a button, nor slide the focus ring back to enable the focus clutch. Just turning the focus ring in it's forward position puts you temporarily in MF mode.
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The real purposes of a focus clutch are these:
- with the focus ring back, you have
absolute position control of the focus ring. There are hard stops for near and infinity. The travel of the focus ring is limited to some 45 degrees. Just like with old mechanical lenses you get a tactile position feedback. To many people coming from the MF film days, this absolute position control is worth gold! It gives them back the familiar feel of a truly manual lens.
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you can put a manual focus position into memory. And you can return to this exact position at any time, just by sliding the focus ring back. Meantime you can do AF or MF with the focus ring in it's front position, as often and as long as you want, and taking pictures. But as soon as you pull the ring back, you re-establish the exact memorized focus position.
Example: you have established a focus from a given location you are standing or sitting. And now you are waiting for an event to happen. In the meantime you want to take some pics say of the surroundings. As soon as you see the event you were waiting for begins unfolding, just slide the focus ring back to the memorized distance and shoot. No need to wait for AF to establish focus.
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you can preset a manual hyperfocal focus distance. Using the hyperfocal scale that is revealed as you slide the ring back. Completely independent from what you do with AF or MF. Whenever you pull the ring back, you re-establish that preset hyperfocal distance.
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By the way, the name focus clutch is misleading. In m43 it is not a true mechanical clutch. It is still focus by wire technology. It electronically mimics the operation and feel of a mechanical focus clutch. It is a virtual focus clutch. And because of that, the closest focus distance is longer than when using AF, or when using MF with the focus ring in forward position. And the infinite focus stop is also not spot-on as it is with manual lenses. But it is still way better than standard AF lenses where the focus ring rotates infinitely with the added crutch of two-speed sensitivity.....
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All that said, I think that people that grew up with AF alone are less likely to appreciate this focus clutch feature. And vice versa.
- people that grew up with AF are less likely to understand how (and why) to use hyperfocal distance settings. They are used to rely on AF, and yes AF has become a lot faster. But there are still situations, like when it is too dark for AF to work fast and reliably or other objects trick AF, when Hyperfocal settings still make sense to shoot fast action.
- People that grew up with AF are less likely to even know what absolute control of the focus ring means and feels like.
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PS: and just a reminder, not only expensive big and heavy pro lenses have the focus clutch. The small and lightweight 12/2 and 17/1.8 have it too!!! I have both these lenses, and not once did I accidentally and unknowingly activate the clutch. It just does not happen, because the lenses are so small the focus ring does not catch when taking out or putting into a bag. Unlike say the 40-150pro, where the focus ring regularly gets dislodged because the large lens is a tight fit in my bag.
. And quite heavy too with 654g.
