41MP

BDR-529

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can please someone tell how the diffraction mpx limit is defined?
Diffraction does not limit number of megapixels per se. It just limits the smallest size of pixel for any given wavelength and F-number.

Due to diffraction any point source of light turns into Airy disk and sensor can't distinguish two point sources after the diameter of Airy disks is at least twice the the size of single pixel. Airy disk becomes larger as F number increases and aperture size decreases.

If we take the "41MP" IMX492 sensor as an example, it has pixel size of 2,315um and therefore diffraction will start limiting resolution after F4.

Note that resolution is limited by either aberration or diffraction whichever comes first and I seriously doubt whether even best MFT primes are up to the requirements of this sensor because it equals over 160MP FF sensor. Aberration is a collective term for all optical defects which limit what we know as lens "sharpness"

To add insult to injury, aberration reduces resolution wide open so lens has to be stepped down but in this example (41MP MFT sensor) diffraction will kick in almost instantly and leave us with, say, from F2 to F4 for maximum resolution which is really on par with the sensor pixel count (pixel size really).

This will only have impact on pixel peepers though since who would ever view 41MP MFT images in their native resolution anyway.
 
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MichailK

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that is why I was asking about 50% all over vs, say, 75-25% which retains information, all this for a theoretical perfect lens

so in essence, in good light, a 41mpx bayer sensor will practically leave only the lens as the limiting factor of RAW IQ and would be the mpx ceiling for the system
 

BDR-529

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so in essence, in good light, a 41mpx bayer sensor will practically leave only the lens as the limiting factor of RAW IQ and would be the mpx ceiling for the system
Yes, you can forget about diffraction as resolution reducing component for sensor with 2,315um pixels assuming that you can shoot at F2 or faster.

Diffraction is not an on/off thing though. It's there even at F2 although not yet as a significant component but at F5.6 and above Airy disks overlap on adjacent 2,315um pixels and diffraction caps resolution even if the lens is theoretially perfect without any aberrations.
 

WhidbeyLVR

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Most of this diffraction discussion seems too nit-picky for me. Neither lens limitations nor diffraction are going to make the image on a 41 MP sensor worse than the same image on a 16 or 20 MP sensor, and might make it better for certain lenses and apertures.

And while you may not be able to resolve significantly finer detail, you will find diffraction softening of edges on larger features quite amenable to computational sharpening. Macro shooters do this all the time as a trade-off for greater depth of field, with excellent results.

Removing the sensor resolution as a limiting factor and living within the limits of physics seems like a good thing to me, even though “diminishing returns” is the order of the day. The primary downside is image file sizes and bandwidth requirements.
 

MichailK

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for stills, if we discount the few ultra sharp lenses in the system (in the middle of the image circle), is there any practical benefit vs the current 20mpx sensors if DR and noise performance is similar?

if fast readout, AF performance maybe?
 

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For those concerned about diffraction, one can take a look at some real world scenarios.
Eg. Nikon 1 went from a 10MP FSI sensor in the V1 to a 21MP BSI sensor in the J5 (both 2.7X crop factor).
It translates to a m43 pixel density from ~18MP FSI to 38MP BSI. So it’s pretty close to what we’re talking about here.

Take a look at the real world results and make up your own mind whether diffraction’s a big issue.
 

WhidbeyLVR

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For those concerned about diffraction, one can take a look at some real world scenarios.
Eg. Nikon 1 went from a 10MP FSI sensor in the V1 to a 21MP BSI sensor in the J5 (both 2.7X crop factor).
It translates to a m43 pixel density from ~18MP FSI to 38MP BSI. So it’s pretty close to what we’re talking about here.

Take a look at the real world results and make up your own mind whether diffraction’s a big issue.
You could also look at the OM-D HiRes modes as a stand-in for a higher resolution sensor. The camera is constructing a virtual 50 MP HiRes sensor by over-sampling with offset pixels and sharpening the result. (Actually, more like an 80 MP image which is sharpened and downsized to 50 MP). If there is extra real detail in a HiRes mode image with any given lens, you should be able to expect some benefit with a higher pixel count sensor, as well.
 

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I'm not a sports/action type of shooter, my photography is mostly landscapes and abstracts, so I tend to take my time, no hurry, careful composition, but I still noticed my E-M1 II getting hot at times, which kinda shocked me at first.

When I bought my C-7070WZ, digital was still kinda of in its infancy, not really mature yet. Now the technology is so advanced, and feeling the heat of E-M1 II on my hands reminded me of that. There is already so much going on under the hood, the limit probably has been reached for now.

It would have been nice if E-M1 III came out a few months earlier, I could have gotten an extra stop of IS and the hand-held hi-res, but overall I think it's kind of diminishing returns for bodies now. I think that's where all the hype being generated over full frame stems from also. Manufacturers just want people to keep investing in new camera bodies somehow.

I think if photographers want higher resolution, lenses are a much better long term investment now. I chose 12-100mm F4 as my starting lens and now I'm waiting for the 100mm Pro macro, for example. I am not sure I will spend money on another camera body in my life. E-M1 II is my first, and it could also be my last. But I will get more Pro lenses for sure.
 

RAH

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You could also look at the OM-D HiRes modes as a stand-in for a higher resolution sensor. The camera is constructing a virtual 50 MP HiRes sensor by over-sampling with offset pixels and sharpening the result. (Actually, more like an 80 MP image which is sharpened and downsized to 50 MP). If there is extra real detail in a HiRes mode image with any given lens, you should be able to expect some benefit with a higher pixel count sensor, as well.
I've done some hi-res mode photography with my E-M5.3 and I would say it definitely gives you more detail than regular. So I guess we could consider a 41MP camera to be one with full-time, unrestricted hi-res - in other words HHHR on steroids (41MP is close to 50MP). I guess this is obvious, but just a different way of looking (literally) at things. I want one!!
 

WhidbeyLVR

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I've done some hi-res mode photography with my E-M5.3 and I would say it definitely gives you more detail than regular. So I guess we could consider a 41MP camera to be one with full-time, unrestricted hi-res - in other words HHHR on steroids (41MP is close to 50MP). I guess this is obvious, but just a different way of looking (literally) at things. I want one!!
The part of HiRes mode you will not automatically get from a new sensor is the lower noise from stacked oversampling. So you still have to be careful with your exposure (or stack or use built-in HDR modes).
 

stratokaster

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For stills use, the 41Mp is sure nice to have, but my big hope is that it comes with improved DR/noise performance (at the final image level). There's historical support for this - Sony's R models added megapixels and improved DR at the same time.
I thought the 20MP sensor was already limited in terms of DR by the 12-bit pipeline? The IMX492 doesn't support 14-bit readout as far as I can see.
 

cnyap

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My DJI Mavic Air 2 has a tiny 1/2” sensor (Sony IMX586) with 48MP, but it uses a 12mp color filter. Best way to think of it is a 12mp sensor, and the “extra” pixels allow it to do HDR in one frame (still images and video too). It works fantastic - perhaps M43 will get a HDR sensor some day.
 

Photon

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Diffraction does not limit number of megapixels per se. It just limits the smallest size of pixel for any given wavelength and F-number.

Due to diffraction any point source of light turns into Airy disk and sensor can't distinguish two point sources after the diameter of Airy disks is at least twice the the size of single pixel. Airy disk becomes larger as F number increases and aperture size decreases.

If we take the "41MP" IMX492 sensor as an example, it has pixel size of 2,315um and therefore diffraction will start limiting resolution after F4.

Note that resolution is limited by either aberration or diffraction whichever comes first and I seriously doubt whether even best MFT primes are up to the requirements of this sensor because it equals over 160MP FF sensor. Aberration is a collective term for all optical defects which limit what we know as lens "sharpness"

To add insult to injury, aberration reduces resolution wide open so lens has to be stepped down but in this example (41MP MFT sensor) diffraction will kick in almost instantly and leave us with, say, from F2 to F4 for maximum resolution which is really on par with the sensor pixel count (pixel size really).

This will only have impact on pixel peepers though since who would ever view 41MP MFT images in their native resolution anyway.
I have always wondered if higher resolution sensors may have more benefit than than it seems since each pixel really only captures a single color.

For instance, an 80 megapixel micro 4/3 camera could be down-sampled to a 20 megapixel image with full color information at each "pixel."

The camera manufacturer could even allow the user to "unlock" the full high resolution mode at apertures that make sense, and provide a smaller file at apertures that suffer from diffraction. I think Olympus already does this to some extent with aperture limits on their high resolution modes.

As for me, I am still using a 16 megapixel sensor and am perfectly happy. But it would be interesting to see what extra pixels could provide.
 

Photon

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My DJI Mavic Air 2 has a tiny 1/2” sensor (Sony IMX586) with 48MP, but it uses a 12mp color filter. Best way to think of it is a 12mp sensor, and the “extra” pixels allow it to do HDR in one frame (still images and video too). It works fantastic - perhaps M43 will get a HDR sensor some day.
Pretty cool stuff. I suspect micro 4/3 will get that type of technology eventually. I personally think Olympus and Panasonic are just waiting for a meaningful advancement in technology before investing in a new sensor.
 

Mike Wingate

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  • Thread Starter Thread Starter
  • #59
I want more. And keep it small sizes. Panasonic did not seem to sell many mirrorless cameras last year compared to the other manufacturers.
 

mike3996

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While I fully acknowledge that more megapixels never hurt the image quality (the discussion in this thread about diffraction limits has been wonderfully accurate AFAIU) I surely hope the new sensors wouldn't go overboard with the pixel counts.

Ultimately people have to realize that a small sensor is not a large sensor; the pixel count doesn't make the sensor size, physical dimensions do. You can't cheat physics by cramming more pixels to a silicon chip of same area.

I also hope that by this time people realized that the megapixel races are over. Canon is happy to launch a 20 MP full frame camera, people are happy with marginally larger 24 MP sensors. M4/3 doesn't need much more because the diminishing returns are met quicker with the smaller sensor size.
 
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