Sony NX80 video is grainy?

[Jeremy Lee]

I am coming over from the Sony A7iii whereas I didn't often have situations where my video was grainy. I am somewhat new to video so seeing noise in my NX80 footage is making me wonder if that is normal. Typically I am shooting indoors, f2.8, 3dB, 60-shutter, and I am filming 4K XAVC S. Do any of you have any suggestions? Thanks

[Christopher Young]

Using an A7iii and a Z90 here, the same sensor as your NX80. I understand your pain:)

Your A7iii has a sensor with a diagonal of about 43mm and your NX80 has a sensor diagonal of 15.86mm.
That's a crop factor of just about 2.71

The NX80 has a pixel count (effective) of 14.2 megapixels with a pixel size of 2.4 µm. The A7iii has a pixel count (effective) of 24.2 megapixels with a pixel size of 5.93µm.

The fact that the A7iii has approx 10 megapixels more in the way of photosites than the NX80 and that those photosites are almost twice the size has a dramatic impact on the SNR (signal to noise ratio) of the images captured by both cameras. There is no way you can hope to get anywhere near as quiet an image with the little 1" NX80 sensor over the larger 43mm FF sensor of the A7iii. Even at '0' dB the A7iii's SNR is well below that of the NX80/Z90 sensor family.

I find depending on lighting levels I can use up to about 12dB on the Z90. And that's at a push! As a rough rule of thumb guide to what 12dB on the NX80 equates to on the A7iii have a look at the table below:

-3db is the equilivant of ISO 200
0db is the equilivant of ISO 320
+3db is the equilivant of ISO 400
+6dbis the equilivant of ISO 800
+12db is the equilivant of ISO 1250
+18db is the equilivant of ISO 2500+

As you can see 12dB equates to about ISO 1250 which as you would well know on the A7iii displays no noticeable image noise at all at that setting. Sadly not in the same boat race when it comes to "grain" as you put it.

That said the NX80 the AX700 and the Z90 with their little 1" sensors have a very useful place in production and can be used quite successfully side by side with the A7iii given decent lighting situations. I have used the A7iii and the Z90 together and have been very happy with the results from both of those two cameras given the right conditions.

Chris Young

[John Nantz]

Christopher … what an interesting post! This is a keeper!

Haven’t owned a still camera since, sadly, selling my vernable Nikon 35 SLR (no “D”) years ago. Today, the only thing I’ve got is the iPhone and the still frame on the cam. HOWEVER, the post sheds new light on the potential use for a still camera.

Currently, I’m at a crossroads in what to do with video with no thanks to COVID. Everything life-wise has changed and there is effectively no social interaction, music, or choir videos, so what is there to shoot? Heck, even our cat has mostly grown up. The only thing left is boating (but then only with my wife due to family member requirements) and that season is effectively over with as of next week as we welcome the rainy season (that apparently started early this year). So, when will things open up? January 2022?

In the meantime, I’ll note the table you came up with and think about a possible “still” camera along with how and where it might fit in. You got me thinking!

[Christopher Young]

If it's of help John that's great.

I know all about Covid here in Sydney with practically no work. We have been in a stay at home lockdown since the end of June. It starts to lift on Monday 11th. Fingers crossed.

Stay well now!

Chris Young