What Micro Four Thirds lenses have linear focusing rings?

[Inazuma]

Not sure if I'm gonna get slapped on the wrist again for making this a separate thread. But here we go.

I just want to know which m43 lenses have linear focusing rings? As you may know, most mirrorless camera lenses use fly-by-wire focus systems, which means when you try to focus manually, the change in focus can depend on the speed at which you turn the ring. A linear focus ring would be one where the change in focus doesn't vary by how fast you rotate the ring. 

[Don Kotlos]

I know only of Olympus pro lenses and all manual focus lenses

[cantsin]

The problem is not just linearity, but the fact that focus-by-wire lenses do not have any hard stops at minimum and maximum focus distance. That makes them unusable for follow focus operation (since the physical position of the focus ring is no indication of the current focus point - with the camera resetting the focus point whenever it is being switched off and on again) and any other kind of planned/structured focus pulling.

[Brother]

3 hours ago, Don Kotlos said:

I know only of Olympus pro lenses and all manual focus lenses

Why every lens doesn’t follow Olympus Pro line is this regard is a mystery. 

A very intuitive way to switch from AF to MF in a millisecond. 

[jase]

Summilux 15mm f1.7 has a linear focus ring. Panasonic 20mm as well, yet the focusring sucks balls.

On 4.12.2017 at 6:51 PM, cantsin said:

The problem is not just linearity, but the fact that focus-by-wire lenses do not have any hard stops at minimum and maximum focus distance. That makes them unusable for follow focus operation (since the physical position of the focus ring is no indication of the current focus point - with the camera resetting the focus point whenever it is being switched off and on again) and any other kind of planned/structured focus pulling.

However, hard stops doesnt necessarily mean that you get everything in focus once you hit infinity. For example, the Voigtländer lenses for M43 go beyond infinity once you reach the hard stop. As far as I know this is by-design to overcome reactions of the lens due to very high or low temperature.

[John Matthews]

21 hours ago, jase said:

Panasonic 20mm as well, yet the focusring sucks balls.

I believe it's due to the insanely small design of the lens and having to move a "large" front element whereas faster focussing MFT lenses move smaller elements inside the lens. I've heard it's a great lens though.

[Inazuma]

On 10/12/2017 at 4:26 PM, jase said:

 Panasonic 20mm as well, yet the focusring sucks balls.

Wow, you're right, I didn't realise it was linear. However it takes about 5000 turns to go front infinity to close 

[jase]

17 hours ago, Inazuma said:

Wow, you're right, I didn't realise it was linear. However it takes about 5000 turns to go front infinity to close 

true that... the summilux 15 is way (!) better.

[Don Kotlos]

I forgot to add the excellent Olympus 17mm f/1.8!