24mp sensor for m43? 3.2micron pixel pitch!

Started May 9, 2013 | Discussions thread
oklaphotog Senior Member • Posts: 1,093
Re: Let's hope not........

RicksAstro wrote:

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)

Actually most of the noise is caused by the amplification. Any slight variation in exposure in DPR's test scene makes little impact on noise levels. You need a much bigger difference in exposure to make serious headway in noise above what is created from amplification, so it's a fairly adequate real world example, though not perfect. I'm pretty sure they use the same lights at approximately the same distance. Any difference in shutter @ the same apertures is more likely due to true sensitivity of the sensor vs. what the iso stated at. They are seeking to achieve a certain brightness level, which is appropriate because that is what the end result should be. This makes it much more real world. A handheld meter properly calibrated at a specific ISO is the photographic standard for exposure so if a camera consistently doesn't achieve the appropriate brightness level requiring more or less exposure needed to accommodate that.. That is real world. Anyone who does complex lighting on locations using a combination of studio strobes and ambient mix, like interiors etc.... appreciates this, especially if they use something like a Minolta flash meter with the analyze function.

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.

Why down res? That is only meaningful for small printing. If anything my method is more realistic for larger prints because you can compare the difference of the noise in the lower res file + interpolation artifacts compared to the the higher res file with more noise but less interpolation. The sole reason for a high MP camera is for big prints, as you don't get much of a real world resolution advantage on small prints like an 8x10 or 11x14.

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.

Only when viewing smaller.

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.

Again if you print small.

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.

DXOMark is semi synthetic, which doesn't always truly reflect performance in real world situations and use. Personally, I discount anything above iso 3200 except for emergency or spot reportage use. Even the best FF cameras start taking a big noise dive above 3200.

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