G1 with 20/1.7: "SWITCH TO AFS"

[Jonathon Delacour]

I've noticed that if I have my new 20/1.7 pancake mounted on the G1 and switch from AFS to AFC, a message appears briefly in the viewfinder saying: "SWITCH TO AFS" and, even though the camera is in AFC mode, it operates as if AFS was set. This behavior does not occur when the 14-45 kit zoom is attached. Initially I thought it might be a firmware issue but the same thing happens with both my G1 bodies, one of which has firmware version 1.4 while the other is still on version 1.3.

[Later] I couldn't find any useful information via Google but it occurred to me to check the Panasonic G-series Compatibility Page. Under the Available Focus Mode column, all the Panasonic m4/3rds zooms plus the new 45/2.8 Macro-Elmarit show AFS, AFC, MF whereas the 20/1.7 shows AFS, MF.

Does anyone know (or would anyone be willing to speculate) why AFC mode isn't available for the 20/1.7 pancake?

 

[Terry]

It was said at launch that it didn't do continuous auto focus. In addition, the front element that focuses is supposedly heavier than on the other lenses. So, I just assume this lens would need a strong motor to C-AF and they decided to disable it.

 

[Vivek]

With the even lighter Oly-D 17/2.8 (78g total weight, about 22g less than the 20mm), I think, this is the case.

The power requirements for liveview (videos in other cams) eating up the battery, lens' AF gets lower priority and you are forced to rely on the zooms.

 

[Jonathon Delacour]

It was said at launch that it didn't do continuous auto focus. In addition, the front element that focuses is supposedly heavier than on the other lenses. So, I just assume this lens would need a strong motor to C-AF and they decided to disable it.

Thanks, Terry, that makes sense. It's surprising though that, in their reviews of the lens, neither DPRreview nor SLRgear mention this.

DPReview said:

The lens focuses by moving the entire optical assembly, with a maximum increase in length of a mere 3mm.
​

One would think that the lack of continuous auto-focus would warrant a mention in a supposedly thorough review.

With the even lighter Oly-D 17/2.8 (78g total weight, about 22g less than the 20mm), I think, this is the case.

The power requirements for liveview (videos in other cams) eating up the battery, lens' AF gets lower priority and you are forced to rely on the zooms.

I'm even more surprised that this is also the case with the even lighter 17/2.8.

Just another example of discrimination against those of us who prefer primes.

 

[Vivek]

One would think that the lack of continuous auto-focus would warrant a mention in a supposedly thorough review.

Who supposed that? These "reviews" run to many pages and do not "review" anything useful. IMV, they are nothing but advertisements.

 

[pellicle]

Who supposed that? These "reviews" run to many pages and do not "review" anything useful. IMV, they are nothing but advertisements.

well, didn't amazon buy them?

 

[jerryk]

I
Does anyone know (or would anyone be willing to speculate) why AFC mode isn't available for the 20/1.7 pancake?

I don't know why, but continuous AF is stated as not working with this lens in the GF1 manual.