Skip to the end of navigation

Welcome to the Community!

Alpha - SLT & DSLR Cameras

Showing results for 
Search instead for 
Do you mean 
Reply
Highlighted
Enthusiast
Posts: 3
Registered: ‎10-13-2017
Message 1 of 8 (496 Views)

A7R2: Lens compensations applied even when disabled

[ Edited ]

I don't see a way to put this to regular support, so I'll try here.

 

Short description of the problem: some lenses (e.g. Sony 1.8/55, Voigtländer 2/65), will show concentric colored rings on uniform subjects, for example fog. This is rarely visible, but hard to correct if it happens. It becomes more obvious if you increase saturation. This happens mainly near wide open. Here is an example where you can see the green and purple rings:

 

https://www.dpreview.com/forums/post/60176949

 

 

I have shown that this is due to "corrections" made to the raw file, even when lens compensation is set to off, by disabling the electric contacts. Details: https://www.dpreview.com/forums/post/60207787

 

While the circles are rarely visible in real photos, they are still problematic and require the use of Capture One's LCC feature to fully correct. That the circles appear at all is certainly a problem, but that they also appear when lens compensations are off seems like a firmware bug to me.

 

Chris

Professional
Posts: 1,840
Registered: ‎01-08-2015
Message 2 of 8 (485 Views)

Re: A7R2: Lens compensations applied even when disabled

First, Sony camera's don't apply lens compensation for third party lenses. The fact that you're getting this when using a Voigtländer lens means it's got nothing to do with lens compensation.
¹ The Lens is the Thing
² 'Full Frame' is the new 'Medium Format'
³ "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
Enthusiast
Posts: 3
Registered: ‎10-13-2017
Message 3 of 8 (481 Views)

Re: A7R2: Lens compensations applied even when disabled

They certainly do apply corrections - if you enable corrections, you can easily see the effect, and you can also look at the parameters in the EXIF data. That applies to all third-party lenses with electronic contact, e.g. Zeiss Loxia, Voigtländer.

 

Also, the effect also is visible with the Sony 1.8/55. I just had to use the Voigtländer for testing because the sony becomes unusable with the contacts disabled.

Professional
Posts: 1,840
Registered: ‎01-08-2015
Message 4 of 8 (477 Views)

Re: A7R2: Lens compensations applied even when disabled

Second, multiple published objective test results show that the Sony/Zeiss 55/1.8 vignettes like a son-of-a-gun when used wide open (and uncompensated.) I presume your sample shots were captured using the maximum apertures of the respective lenses, and would be interested to know if the effect persists when you stop down a bit.

Purple/green is a signature of chromatic aberration, and though the S/Z 55/1.8 doesn't suffer from much CA, perhaps some spherical aberration is exacerbating the effect. Again, stopping down might lessen the effect.
¹ The Lens is the Thing
² 'Full Frame' is the new 'Medium Format'
³ "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
Professional
Posts: 1,840
Registered: ‎01-08-2015
Message 5 of 8 (455 Views)

Re: A7R2: Lens compensations applied even when disabled

The primary reason Sony updates the firmware in its cameras is to add its new lenses to the list of lenses it can compensate for, Third party lenses are not compensated for. Check the firmware updates for your camera. You will see that the updates add new SONY lenses to the list of supported lenses.
¹ The Lens is the Thing
² 'Full Frame' is the new 'Medium Format'
³ "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
Professional
Posts: 1,840
Registered: ‎01-08-2015
Message 6 of 8 (407 Views)

Re: A7R2: Lens compensations applied even when disabled

[ Edited ]

Sony tailors its lens compensation on individual lenses. For instance, your Sony/Zeiss 55/1.8 and the S/Z 35/2.8 and 35/1.4 have almost no distortion and chromatic aberration, but loads of vignetting. On the other hand, the distortion in the S/Z 24-70/4.0 is, literally, off the charts bad, and it's vignetting and field curvature (for which there is no compensation) are nothing to write home about.

Sony tunes it's lens compensation for each of its lenses, and doesn't test third party lenses, or include them in its lens compensation feature.

¹ The Lens is the Thing
² 'Full Frame' is the new 'Medium Format'
³ "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
Enthusiast
Posts: 3
Registered: ‎10-13-2017
Message 7 of 8 (381 Views)

Re: A7R2: Lens compensations applied even when disabled

TCav, the parameters for the lens compensations (and many more, for example for AF) are stored in the lens firmware, not in the camera. That's why Sony offers lens firmware updates in addition to camera firmware updates. This way, third party lenses with electronic contacts can include lens compensations too, and all I've see so far do that, at least for vignetting, distortion, and lateral CA. This works similar to the m43 system and was intentionally specified this way by Sony so that 3rd party lenses can use compensations, too.

 

As I've pointed out before, the concentric rings problem also appears on the Sony FE 1.8/55 ZA (see here). The Voigtländer examples are just there to prove that the effect is caused by in camera processing even when compensations are turned off. Please read the full thread.

 

All I am trying with this post is a way give more info to Sony than possible with the "contact support" form.

Professional
Posts: 1,840
Registered: ‎01-08-2015
Message 8 of 8 (358 Views)

Re: A7R2: Lens compensations applied even when disabled

OpticalLimits.com (formerly PhotoZone.de) publishes objective test results for E-Mount lenses with the lens compensation on AND OFF, showing very different results. Therefore, we can conclude that turning off lens compensation actually does turn off lens compensation.

Again, do you get similar results when using smaller apertures?
¹ The Lens is the Thing
² 'Full Frame' is the new 'Medium Format'
³ "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.

Get Social

Share your ideas Watch YouTube Support Videos follow us on Twitter Visit us on Facebook