A7s + Sony Glass: Does Lens Compensation Work While Shooting Video ?

[blafarm]

Been using Canon glass with a Metabones IV.

About to test Sony 24-70 f/4 OSS and 70-200 f/4 OSS lenses and was wondering if A7s Len Compensation worked in video mode.

More specifically, does the Shading, Chromatic Aberration and Distortion Compensation work while shooting video?

Thanks.

 

[hempo22]

I'm also looking at these lenses, my Canon 24-70 is so heavy and pretty big for the camera. F4 is not an issue, especially if the T-stop is 4 and not more lik 5 like the canon 24-105.

 

[blafarm]

I been testing two Canon lenses (16-35 f/4 IS and 70-200 f/4 IS) principally for their weight and IS support -- but they are not parfocul, which is a problem. Also, there are still some nagging interoperability issues (beyond autofocus) even with the latest firmware on the Metabones IV adapter.

I have to assume the Sony lenses will "play nicer" with the A7s -- and they eliminate the need for the Metabones adapter. I know these lenses are not held in highest esteem (more so the 24-70), but DxOMark surprisingly seems to rate the Sony 24-70 f/4 OSS and 70-200 f/4 OSS as being superior to the Canon 24-70 f/4 IS and 70-200 f/4 IS counterparts.

The Sony lenses are reported to be parfocul but they also seem to have the disadvantage of being fly-by-wire. Not much of an issue for still shooters, but my application is 100% video -- so it could be a very big issue. I'll have to see if Sony's implementation of fly-by-wire is too much of an impediment.

However, my understanding is that the in-camera Lens Correction is very important with Sony lenses and I believe it is not applied to RAW images. And that makes me concerned that it is also possibly not applied to video.

I cannot find definitive information on this topic, which is why I posted my question.

 

[draculr]

From my testing it seems to apply the correction to video. The 24-70mm f4 OSS looks absolutely fantastic when filming on the A7S. You just need to work out if the focus ring is workable for you.

 

[blafarm]

Thanks very much for that feedback draculr.

I was wondering if the camera was capable of performing Lens Compensation in real time (Shading, Chromatic Aberration and Distortion) while recording HD and UHD video.

Quick question if you don't mind:

In your testing, did you compare video samples with the Lens Compensation setting turned on and off (or, alternatively, compare RAW stills, which apparently do not have compensation -- to video)?

Or were you just generally analyzing image characteristics such as corner softness and vignetting?

For reference, two somewhat sobering articles relating to the performance of this lens without compensation can be found here and here.

 

[draculr]

In your testing, did you compare video samples with the Lens Compensation setting turned on and off (or, alternatively, compare RAW stills, which apparently do not have compensation -- to video)?

Or were you just generally analyzing image characteristics such as corner softness and vignetting?

For reference, two somewhat sobering articles relating to the performance of this lens without compensation can be found here and here.

I read those articles before going into the store to try it on my own A7S. They did concern me indeed.

My tests were far from scientific. All I did was put it into video mode and shoot the straightest lines I could find @ 24mm, plug them into the stores laptop and look out for distortions. Since the distortions were supposed to be quite severe at 24mm and I could not see any I figured it has to be correcting!

Once I had that sorted out it was obvious the lens sharpness is fantastic for video (as you only need 8MP worth of sharpness for 4K video) and the colours are great. I much prefer the Zeiss colours to the overly warm look the Canon 24-105/24-70 f4's seem to provide.

The only weakness of this lens to me with regard to video use is the focus ring. I hope they release a firmware update in camera to allow for linear focus control rather than the current accelerating control. I tend to use the AF a lot with FE lenses in video but that only helps when setting the focus before recording and not for smooth and quick focus pulling.

 

[hempo22]

The only weakness of this lens to me with regard to video use is the focus ring. I hope they release a firmware update in camera to allow for linear focus control rather than the current accelerating control. I tend to use the AF a lot with FE lenses in video but that only helps when setting the focus before recording and not for smooth and quick focus pulling.

that's too bad.

 

[blafarm]

Thanks for that comprehensive reply.

I hope they release a firmware update in camera to allow for linear focus control rather than the current accelerating control.

I guess I'm going to have to try this out myself, but are you saying there is not a 1:1 relationship between the rotation of the focus ring -- and the resulting movement of the lens? And, if so, do you find it overly challenging to achieve fine levels of perfect focus because of the "acceleration"?

I tend to use the AF a lot with FE lenses in video but that only helps when setting the focus before recording and not for smooth and quick focus pulling.

Not having used Sony glass, may I ask what your technique is regarding using AF before recording video? Do you half press the shutter button (which is not available in a Movie Mode) to force the lens to focus on your subject -- and then initiate video recording using the dedicated movie button? Or, are you using the Continuous AF function on the Focus Mode menu item?

By the way, you might be interested in this article regarding shooting video in Stills Mode versus Movie Mode.

 

[wallrc]

The focus ring does indeed blow on the 24-70. Autofocus while shooting actually works though.

 

[blafarm]

The focus ring does indeed blow on the 24-70. Autofocus while shooting actually works though.

How are you locking the focus on your subject while still allowing for camera movement?
In other words, how are you preventing the camera from hunting a new focus point?

 

[PSA1]

How are you locking the focus on your subject while still allowing for camera movement?
In other words, how are you preventing the camera from hunting a new focus point?

It has face recognition which works very good so once it lock into the face it will track, I'm a manual focus guy all of my life since ENG camera but now just start playing with it I think I will use auto focus from now on, or you can also leave it in manual focus and press the focus button and hold it and it will switch to auto continuous with face tracking, (you have to turn on face tracking feature)and when the subject stop moving you can let go of that focus button and it is back to manual focus. It also have center lock focus which lock on and track the nearest object if you are not shooting people.

 

[draculr]

Thanks for that comprehensive reply.

I guess I'm going to have to try this out myself, but are you saying there is not a 1:1 relationship between the rotation of the focus ring -- and the resulting movement of the lens? And, if so, do you find it overly challenging to achieve fine levels of perfect focus because of the "acceleration"?

Not having used Sony glass, may I ask what your technique is regarding using AF before recording video? Do you half press the shutter button (which is not available in a Movie Mode) to force the lens to focus on your subject -- and then initiate video recording using the dedicated movie button? Or, are you using the Continuous AF function on the Focus Mode menu item?

By the way, you might be interested in this article regarding shooting video in Stills Mode versus Movie Mode.

No problem. I'm still experimenting with the continuous auto-focus and face tracking. Sometimes it works amazingly well other times it seems way too slow. I haven't got enough experience with it just yet to make any definitive statements.

With regards to the acceleration, the amount you need to rotate changes based on the speed you turn the ring. This is good for fine tuning focus I suppose, but for video use it's really bad. It just means that you can't do the old "i'm going to focus x degrees to hit my mark" trick. So you end up just trying and trying until you finally hit the focus point. At least with an f4 lens you don't need to be that accurate. The 55mm 1.8 and I'd imagine any other FE lens has the same problem.

It would be amazingly simple for them to fix the problem by adding the option of linear focus rotation. Hell, let us enter in exactly how many degrees of rotation we want and even choose the focus direction! We should petition Sony

 

[blafarm]

Well, I knew I had to get dirty and test this myself.

Couple of observations:

1. When using the Sony 24-70 and navigating to Lens Compensation, the Distortion Compensation option is grayed-out and set to Auto. This is the case regardless of whether the camera is set to JPEG or RAW -- meaning, it cannot be adjusted by the operator. If someone is seeing something different please let me know.

2. The 70-200 lens does not behave this way, Distortion Compensation can be switched on or off by the user regardless of JPEG or RAW settings.

3. Getting back to the 24-70, when shooting a straight horizontal line at 24mm in RAW, the barrel distortion is obvious (as supported by my two previously supplied links). Meaning, that regardless of the grayed-out setting, RAW mode does not include Lens Compensation.

4. However, when recording video without changing any settings from the RAW mode listed directly above, the barrel distortion is gone. So, the camera must be performing Lens Compensation in real time when recording video. This is encouraging.

5. I've answered most, if not all, of my focus questions. I was coming from a Canon/Metabones setup -- but you just have to use the camera with Sony glass for a couple of minutes for it to become clear.

I come from a manual focus world too, and I'm not too pleased with the focus ring action of the 24-70. But I have to admit that the dedicated focus button on the camera body is a very useful tool and I think I can live with that lens.

For the record, the 70-200 is much better in that regard -- although my lens seems soft at 70mm (which has been reported in the previous links).

Finally, I'd have to say I think there's a zero chance that Sony will revise the focus firmware to allow the 24-70 to operate in a linear fashion. So, in my opinion, you have to make your peace with that lens -- or walk away.


Edit:

One last thing. These lens are not completely parfocul (although the 70-200 is much closer than the 24-70). However, they are much better than the Canon glass I had been using. Like everything else in the world -- there are trade-offs.