24mp sensor for m43? 3.2micron pixel pitch!

Started May 9, 2013 | Discussions thread
RicksAstro Veteran Member • Posts: 3,730
Re: Let's hope not........

oklaphotog wrote:

seachicken2000 wrote:

oklaphotog wrote:

But if those were iso 3200 files, the 24mp Nex-7 file would show more noise as we're slightly pushing both files past their original size.

I find I get similar quality high ISO images from my 16 and 24M pixel NEXs (using Lightroom).

For example below (the best I could do from the DPR RAWs for each image) at ISO3200 I'd say the NEX-7 image has about the same level of noise, but it's finer grained, and the image is a touch more detailed.

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"The only thing that gets in the way of a really good photograph, is the camera"
Norman Parkinson

But this doesn't really show it, you've picked a bright area of the scene instead of the shadows where the differences are much greater on any camera. Also you have used noise reduction. Most people going for ultimate image quality will use 0 luminance and try to stay away from more than 25 color and trade a little grain for better resolution.

For many of us we run from NR, as quick as possible. Here's a more realistic scenario between the two in the shadows. Left image is from the nex-6 uprez'd to the same size as the nex-7 which is on the right. ISO 3200 and no noise reduction. This shows what is really going on in the sensor.

ISO 3200 Nex-6 on left scaled up to the same size as Nex-7 on the right.

Not a huge difference, but it is there. Probably a stop or so.

Since the NEX-7 is indeed slightly worse above ISO3200 on DXOMark, it stands to reason it's slightly worse in the underexposed areas at ISO3200.

But you really can't use DPR's examples to judge this.   They do not control the light reaching the sensor, so comparisons are really not valid.   In your example above, the shutter for the NEX7 is 1/1000 and the NEX6 is 1/800.  And we really have no idea of the studio light intensity. So who knows how much light was actually hitting the sensor (which is the main determining factor for noise in these mostly ISO-less cameras)

Also, I've found upresing to the larger pixel count really isn't a great method to visually judge noise.   Of course the NEX7 shows more high frequency noise since it's at full res...the nex6 couldn't possibly show that high frequency noise.    I find it a more effective tool to downres either to a common resolution or to the resolution of the lowest.

And even with all of that, there is at most 1/3-1/2 stop difference.   Just look at the same area with the NEX6 set to ISO6400...it has more noise even at the 100% pixel level.   Viewed at the same magnification, the nex-7 is clearly better, so the difference is far less than one stop.

Finally, I've found noise reduction software if far more effective with higher res files when viewed at the same magnification as lower res files, keeping more of the fine detail.

Bottom line is I think DXOMark's graphs reflect reality, and the performance of these cameras is similar through most of the range, with a slight (about 1/3 stop) advantage to the NEX6 above ISO 6400.

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