Where Is the Camera Industry Headed In this Ridiculous Resolution War?

Started 2 months ago | Discussions thread
Erik Kaffehr
Erik Kaffehr Senior Member • Posts: 2,963
Not much of a race..

Hi,

Pixels are getting smaller. One of the reasons is that the wiring and transistors are getting smaller so the balance between wiring and active area of the photodiode is getting smaller.

Another trend is BSI, back side illumination. BSI essentially move the wiring behind the sensor.

All that really means is that optimal size of the pixel gets smaller. It is of course true that reducing the size of the pixel reduces both DR and noise at the pixel level, but having more pixels compensates for that.

Modern small pixel sensors have better SNR and DR than older large pixel sensors. Best demonstration may be the Sony A7xx that is made in 12, 24, 42 and 61 MP variations.

Here you see that the 42 MP A7rIII performs as good as the 24 MP A7II! and mostly better than the 12 MP A7sII.

Keep also in mind that a 24 MP sensor has 6 MP red and blue pixels. That in connection with sampling means that say 24 MP sensors on 24x36 need antia aliasing filters, which throw away resolution. That is because there is a mismatch between the resolution of lenses and sensors.

Making the pixels smaller allows removal of the AA filters. But lenses may get better, if so aliasing will come back.

I think I bought my first 24 MP APS C-camera back in 2012. At present APS-C is around 26 MP, I think. Eight percent increase in seven years is not much of a race.

Now, taking that 26 MP and scaling up to 24x36 mm you get 61 MP and that is exactly where the Sony A7rIV is. Scale it up to 44x33 mm and you get the 102 MP used in the Fujifilm GFX 102 and going to 54x41 mm you end up with 151 MP sensor used in the Phase One IQ4150.

All those cameras use the same pixel design.

What I see is not a megapixel race, but rational development that makes perfect sense.

I would also say that old pixels having better colours is mostly a myth.

The images here were shot on:

  • Phase One P45+ (2007, Kodak CCD, 6.8 micron pixels, 49 x 37 mm sensor, 39 MP)
  • Sony Alpha 900 (2008, Sony CMOS, 6 microns, 24x36 mm, 24 MP)
  • Sony Alpha A7rII (2015, Sony CMOS, 4.5 microns, 24x36 mm, 42 MP)

Personally, I don't right now know which is which. Can you see a difference?!

Would you be interested in a detailed study, here is a layered TIFF:

http://echophoto.dnsalias.net/ekr/Articles/Temp/Tricolore/Stacked_with_samples.tif

The TIFF includes small patches of measured color from the actual fruits.

Best regards

Erik

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Erik Kaffehr
Website: http://echophoto.dnsalias.net
Magic uses to disappear in controlled experiments…
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Articles: http://echophoto.dnsalias.net/ekr/index.php/photoarticles

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