Sony A7S produce much Noise in ISO 3200

B

bounce187

Member
Hi Friends,

i am a german guy - so sorry about my bad English.

I´m not happy about my Sony A7S. Before i buy this Camera i read all the tests in the Internet where they say the A7S Camera is a "ISO MONSTER".

Before the i filmed with it, i make my Jobs (Club / Events / Aftermovies) with the Canon 6D. And till now, i dont find a different in ISO-Skills.

Here is a Screenshot. Left with S-Log2 and ISO 3200, right the same with a curve.

Is that normal?

I hope you unterstand me and i hope the Jpeg Compression ist not to big and you see what i mean.

Best wishes
Johannes

https://dl.dropboxusercontent.com/u/32064511/vergleich.jpg
 
yes, it's normal. the noise is there to hide the 8bit banding. get neat video. i bought it along with the camera.
or
shoot in cine mode.
 
It's very normal with any digital camera that if you underexpose you will get noise. Don't underexpose if you want clean images. All cameras have noise in the shadows, especially those with a large DR and flat/log curves, and if you place important detail in the shadows then that detail will be noisy. The great thing about SLOG2 is you can ETTR and overexpose a bunch and just normalize it in post and compress the shadows so that the noise is hardly visible. Alternatively you could shoot with an in-camera gamma curve that compresses the shadows and stretches the midtones more, you'll have less exposure latitude and will have to nail exposure but you're less likely to see noise in your recorded images since the noisy shadows will be compressed to an even lower part of the curve and so you'll be less likely to accidentally expect that area to be an ok place to put your important detail.
 
Oh thank you!

I think i´ve understood what you wrote.

What Picture Profile do you prefer for Clubs/Discos?

Another Question: When i overexposed in S-log2, how much? +1? +2?
 
I routinely overexpose by one stop. +2 is fine too, usually. +3 starts to have issues relatively often.
 
ah, okay!

is it better to have an iso of 5000-6400 with an overexposed picture instead of a video with iso 3200 that is underexposed?

and what Picture Profile do you prefer for Clubs/Discos?
 
rabbit2 said:
How you can tell how many stops you overexpose?
Click to expand...

Look at the exposure meter at the bottom of the LCD. Also in P/A/S auto-exposure modes you can just turn the exposure dial up. Keep in mind that 'normal' exposure for slog2 is equivalent to about -2EV in most other gammas so don't be afraid to overexpose it.
 
I use a light meter but yes, you can use the exposure indicator from the camera, it's well calibrated (I checked it against the reflective readings of my light meter, with a grey card). Set the exposure method to spot and point the camera to an 18% grey card, when it says +1 you are golden.

And yes, ISO 12800 with exposure +1 will be cleaner than ISO 3200 with exposure -1.
 
Samuel H said:
I use a light meter but yes, you can use the exposure indicator from the camera, it's well calibrated (I checked it against the reflective readings of my light meter, with a grey card). Set the exposure method to spot and point the camera to an 18% grey card, when it says +1 you are golden.

And yes, ISO 12800 with exposure +1 will be cleaner than ISO 3200 with exposure -1.
Click to expand...

Gracias Senior :)

And can you tell me a good Picture Profil except s-log for a good postproduction?
 
Guy Jackson said:
Hey Samuel H, i posted here a short video i shot lately with a A7s (https://vimeo.com/108656778) most of it was shot using your Flaat setting, worked very well, so thank you very much.
Click to expand...
Glad you liked it :)

bounce187 said:
Gracias Senior :)

And can you tell me a good Picture Profil except s-log for a good postproduction?
Click to expand...
Go here. It is based on slog2 but it's not what you expect: watch the "ungraded" El Escorial video and give it a try. Guy Jackson liked it :)
 
Yes with Canon and Nikon DSLRs, if the scene is dark using 6400 ISO actually looks a lot cleaner than 1600 for example. Expose to the right even with ISO, but better with Iris/ND/shutter.

Exposing to the right is termed after the Histogram, it means having the histogram stacked to the right, over exposed.

You just need to make sure you don't clip highlights.

How I expose all my cameras is set the zebras to 100+, then expose up to the highest point before the zebras appear. You can do the same with a histogram or waveform monitor.

For cleanst images, over expose as much as possible without clipping the highlights.

There's another issue many people don't notice is colour channels clipping. Sometimes colour channels clip before exposure clipping, so if you can, over expose without blowing any colour channels or otherwise you'll start getting colour shifts. An ideal tool for ettr is an RGB histogram to watch bith expousre and colour channels. I don't know if the A7s has an RGB histogram though.
 
Hey,

sorry for my many Questions but i find this Forum very helpful to me.

Can i fixed the +2 in the Camera in the exposure settings? So, that the iso regulate the +2? now i make +2 in the dial of the camera but when i filmed in black corners for example it goes down to 0,5+. I hope you unterstand my question.
 
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