SL2 AF half-press blurs EVF

[Jared]

Advertisement (gone after registration)

3 hours ago, bsmith said:

Yes, I'm hoping a firmware update will correct the issue.  The reality is the SL2 AF doesn't always focus correctly, (even when green light is lit) so it's important that we can observe correct focus "before" shooting. If not, what's the point of the hi res EFV or the diopter correction dial? 

It is reasonable to hope for improvements in AF-C via firmware.  However, the pulsation is simply part of how Panasonic’s continuous AF works.  I don’t think it is going to go away until ToF systems get integrated into the cameras.  That will be at least one and maybe two or three generations of cameras from now.  I know it’s something Panasonic is working on diligently since AF has been their greatest weakness for a while when trying to compete against Canon, Sony, and Nikon.  

[Exodies]

ToF needs high precision in the construction of camera, adapter and lens and will reintroduce focus shift with changing aperture. It has the same drawbacks as rangefinder cameras due to the disconnection between the distance measurement and the focus adjustment.

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[Jared]

7 hours ago, Exodies said:

ToF needs high precision in the construction of camera, adapter and lens and will reintroduce focus shift with changing aperture. It has the same drawbacks as rangefinder cameras due to the disconnection between the distance measurement and the focus adjustment.

I doubt it will require high precision in camera construction since lens sample variation would already ruin that as a solution.  Instead, I would expect some sort of closed loop focus confirmation using contrast detection, perhaps as a calibration routine.  That way the ToF system would learn your particular lens.  
 

You also mentioned focus shift.  Don’t we already have that issue?  Not just with rangefinders, but with any lens exhibiting focus shift?  I don’t think the CDAF systems are stopping down for AF. My SL2 certainly doesn’t.  AF is conducted with the lens wide open in all cases as far as I can tell.  
 

The limitation to ToF I believe is more related to parallax and the difficulties of handling different focal lengths.  You would want AF points to cover much of your field of view, suggesting the ToF lens must be a wide angle.  If you then attach a telephoto, digital zoom will only go so far before the relatively large, sensitive pixels in ToF systems are covering a lot more than a model’s eye.  That would, I think, be a challenge.  

Edited March 19, 2020 by Jared

[FlashGordonPhotography]

22 hours ago, Jared said:

Looks like some think the explanation is an actual change in what the viewfinder presents during a half press, while others think it is the contrast detect AF-C pulsing back and forth as it constantly re-confirms focus.  I think it is actually both.

If I have the camera in AF-C there is an obvious loss in visible detail as the AF-C continuously moves things in and out of focus as it re-confirms best focus.  That is definitely happening.  But it’s not the only thing that happens.

If I have the camera set on iAF (where it is only supposed to re-focus if the composition changes), the AF pulsation stops, but there is still a significant blurring of the image while the shutter is half pressed.  The viewfinder literally shimmers just a little bit.  This happens regardless of whether IBIS is turned on and whether the EVF refresh rate is 60fps or 120fps.

If I switch to AFS or to manual focus, the shimmer goes away entirely.  

With AF-C, the stuttering of the focus, which is an integral part of both Panasonic’s and Leica’s continuous, contrast detect auto focus, makes it impossible to judge focus accuracy.  For me, though, and I’m not suggesting this is the case for other photographers, the situations where I use AF-C are dynamic enough that I can’t tell AF accuracy anyway without chimping.  Any time I resort to AF-C, I am entrusting the camera, for better or for worse.  I find it is generally pretty good though not close to the level of a professional sports camera.

I don’t happen to use iAF in any of my profiles, so I hadn’t noticed the shimmering until I tried out various settings today.  In AF-S and manual focus, no issues.

I remember something similar when I got my Q2.  It, I believe, lowered resolution in the EVF at all times except playback.  You could even see it as “stair stepping” in diagonal lines in the information displays such as ISO or shutter speed.  That was/is a different issue.  That issue appears to have been resolved in some firmware release or other since I no longer see it.  That, or my eyesight has significantly deteriorated in the last few months!  The Q2 does have the same AF-C stuttering as all current Panasonic based AF-C systems.  Since the Q2 doesn’t have iAF, it doesn’t seem to have the in-between “shimmering” effect separate from AF-C.

This matches my experience exactly. One of the first things I did was switch out of iAF when I got the camera and I don't have any viewing issues.

 

Gordon

[scott kirkpatrick]

I use almost entirely MF or AFs with PreFocus on, so I hadn't hit this problem.  But when I go to AFc and scan around I see it,  While this has been discussed in the LUF for some time, has anyone turned in strong letter to customer service and gotten an official reaction?

[Jared]

1 hour ago, scott kirkpatrick said:

I use almost entirely MF or AFs with PreFocus on, so I hadn't hit this problem.  But when I go to AFc and scan around I see it,  While this has been discussed in the LUF for some time, has anyone turned in strong letter to customer service and gotten an official reaction?

I’m not aware of any statement from Leica on the matter.  I know that this is the ‘least liked’ aspect of Panasonic’s AFc mode and has been for years.  Videographers, in particular, don’t like it because in their case it not only affects what they see in 5e viewfinder, it is also visible in video files.  It’s probably the biggest flaw in the GH5, for example, an otherwise excellent hybrid/video centric camera.

[Macberg]

Advertisement (gone after registration)

It seems like some time between firmware 2.0 and 5.2, the issue has been corrected. At least I can't see it any more...apart from the stuttering when using AF-C (at the beginning, the blur also occurred when using AF-S).

Edited August 31, 2023 by Macberg