A7s highlight aliasing. Houston we have a problem

[squig]

Rolling shutter is bad but not quite a deal breaker because you can get around it if you're careful, but short of hacking the firmware there's no way to get around the ugly highlight aliasing. I urge everybody to contact their local Sony service centre and demand a fix for it. And anyone who wants to make negative comments about the likelihood of a fix or profess "it's not that bad" can save their breath. Sony fixed the physical clicking on the Nex 5n and I consider this a much bigger bug.

We should hassle Sony to do something about the 30.5mms full frame rolling shutter too. I'm assuming Sony have limited the sensor read speed to prevent it overheating, if that's the case they could add a "skew fix" mode with a faster rolling shutter (preferably around 20ms) at the cost of a shorter record time. Sony are clearly trying to market the A7s as a 5D MK3 killer for video shooters but it's a big leap backwards in terms of rolling shutter and highlights.

On a more positive note the second example clip shot at 60p doesn't appear to have any aliasing (apart from the highlight aliasing), other 60p clips I'd seen previously had nasty skipped/binned type aliasing throughout so I'm a bit confused as to why this footage doesn't. Post processing issue perhaps?

Can somebody test for highlight aliasing with external 1080p and 4k recording.

The following screenshots are 1920x1080 jpegs you can drag to your desktops for a closer look.

UPDATE: The highlight aliasing occurs in all movie modes and on external recordings. I've gone through every function on the A7s, nothing stops the highlight aliasing. It can be black, blue, or yellow.

 

[squig]

I particularly like this one because it suffers from highlight aliasing and rolling shutter.

 

[squig]

https://vimeo.com/99934720

Left shoulder

Can't say I'd be too keen on shooting models with this highlight aliasing

Watch the top of the park bench in the clip. Not really a problem on a 17" screen but I'd hate to see how the highlight aliasing looks on a 50ft screen!

 

[macgregor]

Does this happen in slog mode?

 

[squig]

Does this happen in slog mode?

That first scene is S-log.

 

[Samuel H]

Yes. The description in the first video squig posted says:

Slog, s gamut, +2 phase, -7 detail, -3 saturation, white balance all over the place. night went to 2500k a lot so it gets noisy. Shot at 24 FPS with 1/50 shutter (no 1/48 or 180 degree shutter available). I think a few times by accident we shot at 1/40 shutter. I noticed that in some of the subway shots. Shot at 1080p 50 MBPS XAVC HD codec in camera.

So, next question: does external recording fix the highlight aliasing issue in the FS700?

(also: I didn't notice any of this the first time I saw those clips; this is no 5D2 rainbow moire: we are getting pickier with our pixel peeping)

 

[ReelWorksMedia]

Eeech, man, that's one to many checked boxes on the "cons" list. I have really wanted to add this little guy to the rig. It just seems to me that it's just not where it needs to be to perform on a regular basis in the type of work I do. Big bummer. I commend it for it's positives. It's a nice step in the right direction. I believe I'll wait to add the next iteration of this sensor to the collection.

 

[squig]

Yes. The description in the first video squig posted says:


So, next question: does external recording fix the highlight aliasing issue in the FS700?

(also: I didn't notice any of this the first time I saw those clips; this is no 5D2 rainbow moire: we are getting pickier with our pixel peeping)

I just got glasses. I can see! :2vrolijk_08:I noticed it on Philip Blooms Brighton shots too. Heavy web compression makes it a lot worse.

 

[macgregor]

Decoding issue perhaps?

 

[squig]

Decoding issue perhaps?

I doubt it, the 5D MK3 does something similar in dual ISO mode. We'll know for sure when somebody hooks up a ninja.

 

[stefanhuberfilms]

So, next question: does external recording fix the highlight aliasing issue in the FS700?

only if you record via the 7Q 4KtoHD or 4K RAW...

this is a bummer for the HD mode! I don't think this will happen in external 4K recordings though...

 

[cpc]

Looks more like contouring than aliasing.
FWIW, there is a manual setting under Detail in the profile options for "crispening"; this could lead to something similar.

 

[squig]

I can see it in Philip Blooms 4k shots, much harder to spot but that could just be because of the light.

Aliasing on the "and" on the paint can 1:49, and on the top edge of the gutter 1:20 (top right corner of screen)

 

[squig]

Contouring?

I'll have my films contour less thanks.

 

[cpc]

Yep, edge enhancement, contouring, or whatever this is called in this language, the aliasing is a result of the artificial black edge.

 

[squig]

Yep, edge enhancement, contouring, or whatever this is called in this language, the aliasing is a result of the artificial black edge.

If it was edge enhancement it wouldn't just be happening to the highlights.

 

[philip bloom]

I can see it in Philip Blooms 4k shots, much harder to spot but that could just be because of the light.

Aliasing on the "and" on the paint can 1:49, and on the top edge of the gutter 1:20 (top right corner of screen)

Are you finding this in the actual downloaded version of this as analysing this stream is naturally not a thing to do. I even say in the title "for download". Also do you know how much sharpening I had on this? Worth noting for sure as it may or may not have a different impact on what you are seeing. It was all shot sharpening 0 apart from the S-Log 2 that was sharpening -7

p

 

[cpc]

If it was edge enhancement it wouldn't just be happening to the highlights.

That's a matter of implementation.
The camera also has a highlights detail setting, fwiw.

The settings may or may not have anything to do with this, but the takeaway point is: even if these black edges happened to be perfectly antialiased they'd still be objectionable.

 

[h-munster]

If it was edge enhancement it wouldn't just be happening to the highlights.

It appears to be happening on high contrast edges -- not necessarily in the highlights. It would be interesting to find a high-key image with less contrast on the edges, and then see if the phenomenon is noticeable.

Also, the phenomenon seems to be inconsistent, even on high contrast edges. So, as others have suggested, variables such as camera edge enhancement settings and post sharpening and grading could be influencing the effect.

 

[squig]

Are you finding this in the actual downloaded version of this as analysing this stream is naturally not a thing to do. I even say in the title "for download". Also do you know how much sharpening I had on this? Worth noting for sure as it may or may not have a different impact on what you are seeing. It was all shot sharpening 0 apart from the S-Log 2 that was sharpening -7

p

Yeah I was looking at the download. It's very minimal on your 4k recording but that could be because the highlights weren't blowing out like on those other clips. If you can get a shot of that gutter and expose to the right recording internally, external 1080p and 4k we'll know if there's any difference.