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TsengVane  Wong

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This problem is just miserable ! The A7s can not work!


Lens:ZhongYi 50mm  f 0.95  Zeiss M 50mm f 1.4
Picture Effect: off
PictureProfile: PP1(Black Level:0ã€Gamma:S-log2ã€Black Gama:Middleã€0  Knee:95% 0  Color Mode: ITU709 Matrix  HL Detail:0)







Lens: Zeiss 24~70mm f 4 E mount  Davici Resolve,LUT: Slog2 to 709


in QT:


Lens:zeiss 24~70mm f 4  E mountã€slog2ã€ITU709

Check you Camera!


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Guest Ebrahim Saadawi

First time I heard of it I thought it was a faulty unit or operator error, but after going through the dvxuser thread above, this is an issue that exists in all cameras. These cartoonish blue artefacts actually turn up in the a7s recorded image o.O

Anyone contacted Sony? they will certainly be responsive with a fix because this is a kind of issue that makes a camera absolutely unusable (if it's as in the OP and accurs randomly).

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looks to me like you;re expecting too much.  I don;t know what your exposure methods are, but I'd have shot nowhere near as hot as you are.  I see that both the lenses you are using are notorious for fringing on ultra high contrast steps.  I think if you closed the apertures down a little this issue would disappear.  Looks to me like your fringing lenses in combination with about as contrasty scenes as you could find, as well as your over hot exposure is causing the issue to be more pronounced.  

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12800 iso is very very high for night filming , take this down to 1250 iso I dont shoot higher than that ever at night , and stop down to f2 this will improve things alot , Rich is right you are way too hot with your exposure so this will lead to issue like this - less is more as they say !!

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I've not shot with the A7s yet, but I have seen the same kind of effect before in some of my shots, in similar (night scene lit by bright street lights) conditions, with another camera.


Without going into an A7s-spesific over-analysing mode, I tend to agree with richg101 and andy lee. To me that looks like a simple case of blue fringing around overexposed (clipping) street lights in an otherwise dark night scene shot with a non-native lens. 


It happens. I believe the easiest way to fix that would indeed be to not shoot such a high-contrast scene so hot. Especially with a non-native lens on such a sensitive camera. Using a native Sony F or FE lens would probably minimise the lens-related colour aberrations in camera, but the clipping highlights in a high contrast scene, especially in a mixed artificial light scene, are begging for coloured fringes, not just with a Sony A7s.

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If I meet nasty colour casts with the C100 I often use the individual sensor R/B gains to adjust, not just the white balancing matrix. For some reason it works slightly differently.


I'm not sure if you can do this on A7s as I don't have it, though may hire one soon. It seems likely blue sensitivity is just part of their sensor system.

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I think it could be something to do with sensitivity to blue plus the large amount of gain applied at high ISO in this camera.


I think it tends to be true that as signal to noise ratio worsens at higher gain levels, clipping characteristics become uglier and the most sensitive channels top-out first.


Canon red channel clipping can be really extreme, and of course Canon are known for exaggerated (but pleasing) red tones.


At lower ISOs there's a load of red headroom in the Cxxx cameras, but the clipping and saturation is harsher higher up.


So my psuedo-scientific judgement is that the camera with clip harder at high ISOs in its most sensitive channel.


The Sony loses out here, as lenses tend to fringe purple and green. Purple has a lot of blue...


It's just a guess though.

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Sony nex-5n and nex-7 (owned both) and the a7s ALL have this exact same thing and have had it for years. It looks effing horrible but for some reason no one else has been that bothered about it until the a7s came along. Maybe because the a7s has higher sensitivity so you can really blow those lights out.


I had this reaction years ago when I compared the nex-5n to the Canon 7d. DXOMark scored the 5n severely higher but I could not see any meaningful difference between them... except that the nex-5n tended to blow out blue leds completely while the 7d kept them way nicer. And that was in RAW stills mode where you can change the white balance. (besides, shouldn't there be a visible chnage in performance as the DXOMark difference was something like 20 points?)


Same thing with the Sony FS700 (before s-log updates etc). One shoot, some led lights. 5d mark III came out beautifully, FS700 looks slightly crap with the blues.


There are ways to try to avoid it (whitebalance to 5000k etc) but it's always there...somewhere. Hiding to come out.

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