Sony A7s: Is my sensor flawed?

[FrankyTwoToes]

Hey all,

 

Came to the forums seeking some help. I bought my A7s used for a good deal a couple months ago and it's been great. I normally just used it in ideal lighting conditions but felt like testing out it's use in low light since that's one of it's strongest selling points. Unfortunately, the levels of noise I'm getting in the blacks and shadows is completely unusuable and totally different then others who have posted their noise tests online (https://www.youtube.com/watch?v=guXnEVou6Lc for example).

Here is some footage I just shot static on my porch. Not a particularly bright night at all mind you.

 

https://drive.google.com/folderview?id=0B9eK_xmGZsW3Nnl4eU5mank2TDg&usp=sharing

 

PP: Cine2 (S-Log was giving me even more noise)
Color: Cinema
Lens: Rokinon 35mm @ 2.0

24fps, 1/50 shutter. X AVCS codec

C0001: ISO 3200

C0002: ISO: 40000
C0003: ISO 80000
C0004: ISO 160000

 

I'm wondering if I could possibly have a sensor issue on my hand and could use input. Thanks for your time.

[Guest Peter Kelly]

To be honest, I'm not a video aficionado so my opinion is not definitive by any means, but I see two issues here that aren't sensor related.

 

The first is that the quality seems most adversely affected by compression more than noise, which makes any value judgement difficult.

Your clips seem to look like old Youtube videos taken on smartphones! I don't know whether this is the settings you've used, or some conversion happening during upload, but I'd suggest you check that first.

 

The second part relates to just how dark is the scene. No matter how good the camera, darkness encourages noise. It is simply about having sufficient light. I think that you say S-log was giving more noise points to the very low light being an issue.

 

You can take shots and video at higher ISO which will be very clean as long as they have enough light; it is when you hope that simply having high sensitivity will make up for a total lack of light that you will be disappointed.

It's a case of balancing results against expectations and it can be tricky to judge from what we see on the internet as to the precise original conditions and how they compare. For instance, the Youtube link you gave does not give a measurement of 'Lux', so who knows exactly how dark it was?

[RRRoger]

No your A7s Sensor is not flawed!

 

It is the rest of the Camera that is flawed.

The A7sII did not solve my problems, but

the 7Q+ recorder when DownRes 4k to 1080P30 helped a lot.

So did the $2500 28-135 Cine lens.

 

I routinely take indoor videos in poor/low light at ISO 6400-12800

There is always some noise in the shadows if you care to pixel peep.

The Cinema guys think that makes the Video more film grain like.

 

Then of course the user is also flawed and we have to learn how to use the A7s properly.