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Author Topic: Sensor Question Why?  (Read 2105 times)

raymond bleesz

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Sensor Question Why?
« on: December 20, 2017, 09:03:01 AM »

It is my understanding that Sony sensors are commonly made for other cameras, FF and mirrorless, from high end MP to less.

Why is it Sony or other companies can not make a 36/47 MP sensor which could be found on upper end DSR's for the upper end mirrorless cameras?  Please explain for example why a Nikon 850 sensor can not be "downsized" in size, yet have the same MPs to work with a high end mirrorless camera, such as a Panasonic gh5.

Thank you--Raymond
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davidgp

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Re: Sensor Question Why?
« Reply #1 on: December 21, 2017, 03:21:43 AM »

You can... take for example a phone sensor of 16/20 megapixeles... with those, a lot of then also made by Sony, you could probably build a m43 sensor with 40 MPx (I have not done the math... so maybe Iím wrong...) you just need to cut the wafers in size of m43 sensors instead of iPhone sensor (well, not exactly but nearly...)

But at the end it is an engineering problem... you have to balance high resolution, DR, noise, speed reading out the sensor information...

When technology evolves allows you to have better levels of noise (cleaner high iso) with more pixels in the same size... but if you build a sensor with lot of megapixeles but much noise than previous generation people will complain... now Sony engineers think 20 MPx is the sweet spot for M43... maybe in two or three years is 30...


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Alan Smallbone

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Re: Sensor Question Why?
« Reply #2 on: December 21, 2017, 10:21:20 AM »

There are lots of reasons, high megapixels in a small sensor, generally are noisier, pixels are smaller, readout speeds for high density in a small package may be slower, the yields in a production run may be lower because of density, higher manufacturing costs due to higher density. Harder to dissipate heat. There are many more reasons, and some just may be marketing and costs.

Alan
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Alan Smallbone
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BJL

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Re: Sensor Question Why?
« Reply #3 on: December 21, 2017, 07:56:15 PM »

I am sure that such a sensor is technologically possible today, from Sony or Panasonic for example: the photosites would be about four times as large (in area) as those in recent phone sensors, and DR and noise levels would be fine for many uses. Also, in cases where the DR or SNR is inadequate, downsampling to a lower pixel count gets you close to the levels that you would get from a sensor of that lower photosite count, so those worries are not as great as some people think. (Selective resolution reduction as with noise reduction processing compares even better fro IQ against lower-resolution sensors.)

I even think it likely that Panasonic will offer a sensor of about 50MP (8192x6144) someday, to follow the 8K video trend.

But for now, the benefits of even more resolution are probably limited to a few extreme cases (like people who print huge, and those who are obsessed with "screen-sniffing": zooming on in little pieces of their images). So for now, the benefits for 4/3" format are probably outweighed by the disadvantages, making it not a good business decision to increase pixel counts substantially. Even discounting worries about DR and noise, the disadvantages of a higher pixel count include lower frame rates, slower buffer clearing after bursts, slower file transfer and processing, more storage needed, more heat production (particularly when recording video), shorter battery life, and so on.

The advantages might increase enough to make it worthwhile if and when:
- enough people are viewing images big screens with resolution beyond 5K (20MP 4/3" sensors are about 5184 x 3888; 5K screens are 5120‑by‑2880.)
- 8K video becomes a significant market.
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