Digital Cameras

Camera sensor size: Why does it matter and exactly how big are they?

How do different sensor sizes compare with each other?
How do different sensor sizes compare with each other?
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Different sensor sizes compared with each other shows how big Full Frame, APS-H, APS-C (Nikon, Sony Pentax), APS-C (Canon), 1.5-inch, Micro Four Thirds, 1-inch, 1/1.2-inch, 2/3-inch, 1/1.7-inch, 1/2.3-inch and 1/3.2-inch sensors are
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Different sensor sizes compared with each other shows how big Full Frame, APS-H, APS-C (Nikon, Sony Pentax), APS-C (Canon), 1.5-inch, Micro Four Thirds, 1-inch, 1/1.2-inch, 2/3-inch, 1/1.7-inch, 1/2.3-inch and 1/3.2-inch sensors are
Different sensor sizes from Full Frame to 1/3.2-inch compared with each other
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Different sensor sizes from Full Frame to 1/3.2-inch compared with each other
Sensor sizes typically used in compact cameras include 1/1.7-inch, 1/2.3-inch and 1/2.7-inch, shown here compared to a Full Frame sensor
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Sensor sizes typically used in compact cameras include 1/1.7-inch, 1/2.3-inch and 1/2.7-inch, shown here compared to a Full Frame sensor
Sensor sizes typically used in DSLRs include APS-C (which varies slightly depending on manufacturer) and Full Frame – APS-H is a size between APS-C and Full Frame which has featured in cameras such as the Canon EOS 1D M4
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Sensor sizes typically used in DSLRs include APS-C (which varies slightly depending on manufacturer) and Full Frame – APS-H is a size between APS-C and Full Frame which has featured in cameras such as the Canon EOS 1D M4
Sensor sizes typically used in higher end compacts such as the Sony RX100, Canon G1 X and the Fujifilm X20 include 1.5-inch, 1-inch and 2/3-inch
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Sensor sizes typically used in higher end compacts such as the Sony RX100, Canon G1 X and the Fujifilm X20 include 1.5-inch, 1-inch and 2/3-inch
Sensor sizes used in mirrorless cameras range from Full Frame to 1/2.3-inch, taking in APS-C, APS-C (Canon) Micro Four Thirds and 1-inch
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Sensor sizes used in mirrorless cameras range from Full Frame to 1/2.3-inch, taking in APS-C, APS-C (Canon) Micro Four Thirds and 1-inch
Ultra high end compact cameras like the Nikon COOLPIX A, Fujifilm X100S and Sony RX1 use either ASP-C or Full Frame sensors
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Ultra high end compact cameras like the Nikon COOLPIX A, Fujifilm X100S and Sony RX1 use either ASP-C or Full Frame sensors
The sensor sizes usually used in smartphones are 1/3.2-inch or 1/3-inch, though the Nokia 808 used a 1/1.2-inch one
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The sensor sizes usually used in smartphones are 1/3.2-inch or 1/3-inch, though the Nokia 808 used a 1/1.2-inch one
The size difference between a Full Frame and APS-C (DX) sensor
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The size difference between a Full Frame and APS-C (DX) sensor
The Sony RX100 is a compact camera with a bigger sensor than most
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The Sony RX100 is a compact camera with a bigger sensor than most
How do different sensor sizes compare with each other?
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How do different sensor sizes compare with each other?
If the HTC One had a Full Frame sensor rather than a 1/3-inch sensor, it wouldn't fit in your pocket, as this comparison with a Canon 5D Mark III shows
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If the HTC One had a Full Frame sensor rather than a 1/3-inch sensor, it wouldn't fit in your pocket, as this comparison with a Canon 5D Mark III shows
What different-sized sensors – Full Frame, APS-C, MFT, 1-inch, 2/3-inch, 1/2.3-inch, 1/3.2-inch – would have captured if using the same lens to take this photo
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What different-sized sensors – Full Frame, APS-C, MFT, 1-inch, 2/3-inch, 1/2.3-inch, 1/3.2-inch – would have captured if using the same lens to take this photo

The megapixel myth has treated camera manufacturers well over the years, those ever increasing, and often meaningless, numbers have sold millions of cameras. But consumers are getting wise to it. We've all seen dodgy images from high megapixel cameras and know that after a point, megapixels don't matter for most people – a 16 MP compact isn't ever going to be as good as a 12 MP Full Frame DSLR. What does matter is sensor size!

Why is camera image sensor size important?

The size of sensor that a camera has ultimately determines how much light it uses to create an image. In very simple terms, image sensors (the digital equivalent of the film your father might have used in his camera) consist of millions of light-sensitive spots called photosites which are used to record information about what is seen through the lens. Therefore, it stands to reason that a bigger sensor can gain more information than a smaller one and produce better images.

Think about it this way, if you had a compact camera with a typically small image sensor, its photosites would be dwarfed by those of a DSLR with the same number of megapixels, but a much bigger sensor. Able to gain more information, the large DSLR photosites would be capable of turning out photos with better dynamic range, less noise and improved low light performance than its smaller-sensored sibling. Which as we know, makes for happy photographers.

The size difference between a Full Frame and APS-C (DX) sensor
The size difference between a Full Frame and APS-C (DX) sensor

Larger sensors also allow manufacturers to increase the resolution of their cameras – meaning they're able to produce more detailed images – without sacrificing too much in terms of other image quality attributes. For example, a Full Frame camera with 36 megapixels would have very similar sized pixels to an APS-C camera with 16 megapixels.

But I thought megapixels didn't matter!

Megapixels are a passionate issue for photographers; they're up there with the "which is better, Canon or Nikon?" debate. Some argue that no-one needs more than 16 megapixels (a couple of years ago it was eight) while others are of the opinion that the added detail is worth the trade off in terms of noise and the computer processing power needed to handle the extra large files.

The truth is that it's always going to be a balancing act between the efficiency of sensor technology, lens quality, image sensor size and ultimately what you want to do with your photographs. If you're going to heavily crop images or print them very large, extra resolution could be useful, if you're only sharing them online or producing normal prints, not so much. What we can conclusively say is that you can only make a call on megapixels in conjunction with considering sensor size.

What are the other characteristics of bigger sensors?

So larger sensors can help you capture better quality images, but they bring with them a number of other characteristics, some good and some bad. The first, and most obvious impact of a bigger camera sensor is that of size; not only will the sensor take up more room in your device, but it will also need a bigger lens to cast an image over it.

This is why smartphone makers generally stick with very small sensors, they want to keep devices pocketable and not deal with the bulk of larger lenses. It also explains why professional photography gear is still so big and heavy. The cost of producing bigger sensors also means that devices packing them also have a bigger price-tag.

If the HTC One had a Full Frame sensor rather than a 1/3-inch sensor, it wouldn't fit in your pocket, as this comparison with a Canon 5D Mark III shows
If the HTC One had a Full Frame sensor rather than a 1/3-inch sensor, it wouldn't fit in your pocket, as this comparison with a Canon 5D Mark III shows

Bigger sensors can also be better for isolating a subject in focus while having the rest of the image blurred. Cameras with smaller sensors struggle to do this because they need to be moved further away from a subject, or use a wider angle (and much faster) lens, to take the same photo. Replicating a Full Frame 28 mm f/2.8 shot on a mobile phone-sized 1/3-inch sensor would take a 4 mm f/0.4 lens!

Angle of view is also something to consider when looking at cameras with different-sized sensors, particularly if using the same lenses between them. Cameras with smaller sensors than Full Frame 35 mm format (seen as the standard) have what's described as a crop factor. So an APS-C DSLR has a crop factor of 1.5x1.6x meaning that it crops into the Full Frame image – using a 28 mm lens on an APS-C giving a view similar to a 45 mm lens on Full Frame.

What different-sized sensors – Full Frame, APS-C, MFT, 1-inch, 2/3-inch, 1/2.3-inch, 1/3.2-inch – would have captured if using the same lens to take this photo
What different-sized sensors – Full Frame, APS-C, MFT, 1-inch, 2/3-inch, 1/2.3-inch, 1/3.2-inch – would have captured if using the same lens to take this photo

The image above shows what smaller sensors would have captured if using the same lens to take this photo. You can see why devices with smaller sensors use much wider angle lenses, especially by the time you reach smartphones. The lenses on these cameras are often detailed by their 35 mm format equivalent focal length to give a better idea of the angle of view they give.

The trend for cameras with bigger sensors

In recent years, camera manufactures have realized that more and more photographers are wanting the sort of better quality images that only come from having a bigger sensor. As such, we've seen devices (from smartphones to DSLRs) being sold with bigger sensors than in the past.

The Sony RX100 is a compact camera with a bigger sensor than most
The Sony RX100 is a compact camera with a bigger sensor than most

Within the smartphone market, Nokia has led the way with larger sensors – currently peaking with the Nokia 808 Pureview, which has a 1/1.2-inch sensor and can produce images to rival many compact cameras. In terms of point-and-shoot cameras, the Sony RX100 brings a 1-inch type sensor to the party, and Canon has released the not-quite-a-compact G1 X with a 1.5-inch sensor.

Mirrorless interchangeable lens systems have also seen small-bodied cameras fitted with larger sensors, typically ranging from Micro Four Thirds to APS-C … which have also made it to enthusiast compacts like the Fuji X100 (now the X100S) and the Nikon COOLPIX A. At the same time, the price of Full Frame DSLRs has also fallen, with the likes of the Nikon D600 and Canon 6D, bringing the affordability of big sensor shooting to a much wider market.

What do different sensor measurements mean?

Manufacturers can sometimes be strangely coy about revealing exactly how big a camera's image sensor is. And even when they do volunteer this information, it's often in a hard-to-understand naming convention … as the last section may have proved. Seriously, how many people would be able to tell you exactly how big a 1/1.2-inch or Micro Four Thirds sensor is without consulting the internet?

Bizarrely, the mostly fractional measurements used to detail sensor size date back to the age when vacuum tubes were used in video and television cameras. But the size designation is still nothing like as simple as the diagonal measurement of the sensor. Instead, it's the outer diameter measurement of a tube needed to produce an image, when the usable image takes up two thirds of the circle. Yes, it's that crazy.

It also doesn't help that different manufacturers use the same title to refer to different sizes, such as APS-C. While a Canon APS-C sensor measures 22.2 x 14.8 mm, the offerings from Sony, Pentax, Fujifilm and Nikon (DX) vary from 23.5 x 15.6 mm to 23.7 x 15.6 mm.

While we'd like to see all camera manufacturers listing the size of their sensors in millimeters, we can't see it happening any time soon. So, in the mean time, here's a couple of graphics showing some of the most common sensor sizes in relation to a Full Frame one.

Different sensor sizes compared with each other shows how big Full Frame, APS-H, APS-C (Nikon, Sony Pentax), APS-C (Canon), 1.5-inch, Micro Four Thirds, 1-inch, 1/1.2-inch, 2/3-inch, 1/1.7-inch, 1/2.3-inch and 1/3.2-inch sensors are
Different sensor sizes compared with each other shows how big Full Frame, APS-H, APS-C (Nikon, Sony Pentax), APS-C (Canon), 1.5-inch, Micro Four Thirds, 1-inch, 1/1.2-inch, 2/3-inch, 1/1.7-inch, 1/2.3-inch and 1/3.2-inch sensors are

Different sensor sizes from Full Frame to 1/3.2-inch compared with each other
Different sensor sizes from Full Frame to 1/3.2-inch compared with each other

Obviously there are also Medium Format cameras with even bigger sensors than those shown here, but if you're in the market for one of those, hopefully you already know how they differ.

What sized sensor is typically used in different cameras?

The sensor sizes usually used in smartphones are 1/3.2-inch or 1/3-inch, though the Nokia 808 used a 1/1.2-inch one
The sensor sizes usually used in smartphones are 1/3.2-inch or 1/3-inch, though the Nokia 808 used a 1/1.2-inch one

Smartphone Cameras – Most smartphones, including the iPhone 5 use a tiny 1/3.2-inch image sensor. In real terms this measures just 4.54 x 3.42 mm and explains how they are able to keep devices so slim and light, but also why image quality and low light performance suffers, especially when they can have as many as 12 megapixels. The HTC One uses a slightly larger 1/3-inch sensor (4.8 x 3.6 mm) and fewer pixels to combat this. The undisputed king of smartphone sensors, the Nokia 808, has a 1/1.2-inch sensor (10.67 x 8 mm).

Sensor sizes typically used in compact cameras include 1/1.7-inch, 1/2.3-inch and 1/2.7-inch, shown here compared to a Full Frame sensor
Sensor sizes typically used in compact cameras include 1/1.7-inch, 1/2.3-inch and 1/2.7-inch, shown here compared to a Full Frame sensor

Compact Cameras – With sensors starting as small as 1/2.7-inch (5.37 x 4.04 mm), it's easy to see why smartphones are making many compact cameras redundant. Budget compacts simply don't have sensors big enough to produce significantly better images. Typical compact cameras such as the Canon IXUS 255 HS and the Samsung Galaxy Camera use 1/2.3-inch sensors (6.17 x 4.55 mm) while more competent ones like the Canon S110, Panasonic DMC-LX7 and the Nikon P7000 come in at a larger 1/1.7-inches (7.6 x 5.7 mm).

Sensor sizes typically used in higher end compacts such as the Sony RX100, Canon G1 X and the Fujifilm X20 include 1.5-inch, 1-inch and 2/3-inch
Sensor sizes typically used in higher end compacts such as the Sony RX100, Canon G1 X and the Fujifilm X20 include 1.5-inch, 1-inch and 2/3-inch

Higher-end Compacts – With demand growing and the price of producing larger sensors falling, there are a growing number of higher-end compact cameras with larger sensors. For example the Fujifilm X20 has a 2/3-inch (8.8 x 6.6 mm) sensor while the Sony RX100 has an even bigger 1-inch sensor (12.8 x 9.6 mm). The Canon G1 X even boasts a 1.5-inch sensor (18.7 x 14 mm).

Ultra high end compact cameras like the Nikon COOLPIX A, Fujifilm X100S and Sony RX1 use either ASP-C or Full Frame sensors
Ultra high end compact cameras like the Nikon COOLPIX A, Fujifilm X100S and Sony RX1 use either ASP-C or Full Frame sensors

Ultra High-End Compacts – Increasing sensor size again are the growing range of ultra high end compacts. These are cameras such as the Leica X2, Fuji X100S and Nikon COOLPIX A, which all feature an ASP-C sensor (23.7 x 15.6 mm) along with a fixed-focal-length lens. There's also the Sony RX1 which does the same, but with a Full Frame sensor (36 x 24 mm).

Sensor sizes used in mirrorless cameras range from Full Frame to 1/2.3-inch, taking in APS-C, APS-C (Canon) Micro Four Thirds and 1-inch
Sensor sizes used in mirrorless cameras range from Full Frame to 1/2.3-inch, taking in APS-C, APS-C (Canon) Micro Four Thirds and 1-inch

Mirrorless Camera Systems – Within the mirrorless camera market, there is a wide range of sensor sizes. The smaller ones include the 1/2.3-inch (6.17 x 4.55 mm) sensor seen in the Pentax Q, and the 1-inch (12.8 x 9.6 mm) sensor used in the Nikon 1 Series. Panasonic cameras such as the LUMIX GF5 and offerings from Olympus (including the PEN series and the OMD EM-5) use a Micro Four Thirds 4/3-inch (17.3 x 13 mm) sensor.

Getting larger still are the APS-C offerings which include the Canon EOS M (22.2 x 14.8 mm) along with the NEX range from Sony and those those from Fujifilm (23.5 x 15.6 mm) … yes, not all APS-C sensors are the same size. Leica rangefinders such as the Leica M have a Full Frame (36 x 24 mm) sensor.

Sensor sizes typically used in DSLRs include APS-C (which varies slightly depending on manufacturer) and Full Frame – APS-H is a size between APS-C and Full Frame which has featured in cameras such as the Canon EOS 1D M4
Sensor sizes typically used in DSLRs include APS-C (which varies slightly depending on manufacturer) and Full Frame – APS-H is a size between APS-C and Full Frame which has featured in cameras such as the Canon EOS 1D M4

DSLRs – By the time you get up to DSLRs and other professional cameras, the sensor size has obviously increased. Most DSLRs whether from Canon, Nikon, Pentax or Sony use either an APS-C (22.2 x 14.8 mm Canon and 23.5-23.7 x 15.6 mm for others) or a Full Frame (36 x 24 mm) sensor. While Full Frame DSLRs have been the reserve of professionals for a number of years, more consumer-focused models such as the Nikon D600 and Canon 6D are now being released.

Summing Up ...

It's clear that more people are realizing that bigger image sensors mean better quality photographs (at least as much as, if not more than, megapixels) and thankfully manufacturers are beginning to cater to this demand with cameras like the Sony RX100 and Nikon COOLPIX A, which are presumably just the beginning.

That said, we'd like to see camera and smartphone makers being a bit more transparent about what size sensor is used in different devices and not hiding it away on some spec sheet in a hard-to-decipher format, or omitting it altogether. Retailers also need to step up and start publishing details on sensor size. It's only knowing (and understanding) this information that will allow consumers to make an informed decision on what they are purchasing.

Obviously, not every device can pack a considerably bigger sensor – as other issues such as form-factor and cost come into play – but do the sensors in smartphones and most compact cameras still need to be so tiny? Yes, the bigger sensor on the Nokia 808 added a significant bump, but few users seem to mind when looking back at their photographs, and a bigger sensor doesn't necessarily mean jumping to those proportions.

As sensor technology improves, we're seeing much better performance out of smaller sensors, but bigger will always be better. Does improved image quality justify the bigger device and price for you? Only you know the answer … but we hope that this guide will help you better understand the importance of sensor size when making your next camera purchase.

49 comments
Keith Reeder
You were doing quite well until this, Simon: "Think about it this way, if you had a compact camera with a typically small image sensor, its photosites would be dwarfed by those of a DSLR with the same number of megapixels, but a much bigger sensor. Able to gain more information, the large DSLR photosites would be capable of turning out photos with better dynamic range, less noise and improved low light performance than its smaller-sensored sibling". Photosite size is IRRELEVANT in the context of this discussion. At the IMAGE level, all that matters is sensor size and the technical state of the art of the sensor. Proof? Well just look at (say) the Nikon D7000 compared to the Nikon D200: the latter has far more, and far smaller, photosites, but kicks the D200 into the middle of next week in IQ terms. Or how about the 18 mp Canon 7D? It is not only FAR better, in IQ terms (and ESPECIALLY at four figure ISOs) than say, the old Canon 8 mp 30D; but it also handily beats older FF and APS-H bodies like the 1D Mk IIn, the photosites of which are HUGE in comparison to the 7D's. You seem to be making the funamental error of comparing results at the "pixel" level rather than at the image level. The simple fact is that - right across the board - IQ has improved along with increased pixel count, on same-sized sensors.
RJB
An excellent and informative article. Thank you.
Paul Gracey
@ Keith Reeder: I think you have a point, but it only goes so far. You must be into conventional flash and full daylight photography to make the statements you do. I , however, am into astrophotography and the gist of this article is exactly right for that pursuit. As a bonus, my first generation Sony NEX-5 is an excellent low light camera even without its flash as long as the subject is in well balanced light to begin with. The IQ you describe applies to this camera over the 8 Meg Canon EOS20D I started with. Being APS-C format helps too with the limitations of my telescope where a full frame could suffer vignetting. Oh, and the older NEX has a lower pixel count than its successors giving more exposed area to each pixel. There is, I think, a sweet spot when it comes to trade-offs, and there is no substitute for area under low light conditions no matter how good the processing. Garbage in nets garbage out.
Rusty Harris
The other thing is Signal to noise ratio. Packing zillions of megapixels on a pinhole camera is just nuts. The signal to noise ratio is going to be so high that unless you are under ideal lighting conditions, the photo is going to come out with so much noise, it will be useless.
Tudor Tihan
16 megapixels in a 2x2 mm sensor results in light hitting more than one "pixel" sensor at a time... You can increase bullshit all you want, but you can't decrease light's wavelength... 16 MP ~= 4000 x 4000 pixels; 2 mm / 4000 = 0.0005 mm / pixel or 500 nm / pixel. If there were absolutely no gaps between light sensing "pixels", you would at this point lose half the red and some of the green light since their length range goes over 500 nm, up to 740 nm.
Franc
DSLRs are great, but not for me when going on holiday. Something not mentioned in the article is the lack of zoom when using a large image sensor. With smaller sensors you can get amazing zoom levels - ideal for focusing on that interesting item in a cathedral or something in the distance. Modern high-tech compacts give you (almost) the best of all worlds. My Sony HX9V Cybershot has optical image stabilization and a 16X optical zoom in a small package. And, best of all, it uses image processing to give superb low light shots - it takes multiple short exposures and combines them to give amazing shots in low light. And you do not look like a nerd with all the gear. The ONLY problem is you lose the ability to play with focus, ie. to get the background out of focus.
weanor
Great article. I wish the cameramanufacturers would take this seriously .The pixelrace we have seen in the past, especially over the last year is just crazy. Why should a regular compact zoom camera have a sensor packed with 16 or even 18 mill pixels, while 10 or 12 mill pixels would in most cases be a much better technical solution both regarding signal/noise ratio and light sensivity as well as better pictures. Nothing but stupid marketing if you ask me. One thing, why have you overlooked Samsung as to highend compacts and mirrorless cameras? They are definitely in the top quality brand series.
Gerard58
All very interesting; however, I have a Nikon D2X, D300s, D5200 and a Sony REX100. The two best shots with excellent picture detail come from my Sony REX-100 and guess what, the D5200. The lens on test with all the Nikon’s I tested was a Nikon AF-S DX 35mm f1.8G. I did this test after taking a shot from the same position with my Sony REX-100 just to compare the shots. I was shocked when I saw the results later. I then bought the D5200 and the extra pixel in my case has made a big difference.
Riaanh
The same as Franc I am also a Bridge camera user. I cannot justify the expense of having a DSLR with 3 lenses, including a 800mm telephoto, which could cost an arm and a leg, and then having to lug all that equipment with you. I have shot everything from a dragonfly to a surfing competition with the same gig. (My brother-in-law has a fancy Nikon, with all the lenses, but could not shoot the dragonfly because he did not have the correct lens with him) - but I do realize that the quality of my images has been compromised by my equipment, but I am not planning on publishing any of my images. (and neiher does my brother-in-law with his fancy kit for that matter, but I had much more fun than him) Interestingly enough Canon has actually lowered the pixel count in their latest range of bridge cameras from 14mps to 12 mps. It is the Canon PowerShot SX50 with an optical zoom of 50x. (2500mm equivalent?!!?) What would you pay for this size of lens for a DSLR? Would you get the wheelbarrow included in the price? Thanks for a very nice article.
Graham
Whatever combination of sensor size and pixel (site) count, there is a quantum physics fundamental that decides all. If the pitch distance between two pixel receptor sites becomes less than 1/4 wavelength of the arriving photons, then the information in both sites will be the same, as if the two together came from a single photon wave. This is a resolution limit no amount of extra pixels can get around without increasing the lens aperture. Bigger lens focused on bigger sensor is more than simply "increasing the amount of light". The size of the available light resolution "mosaic" also gets finer. There is more information in the incoming image. If you look at two objects on the moon through a telescope so close they can only just be seen as separate, them stop down the telescope by placing a smaller aperture mask in front of it: the image will dim, and the two points will merge into one, still perfectly focused, and any extra magnification will not help. This is why we need optics as big as Hubble and more to go after resolution. Putting the same number of pixel (sites) on a bigger sensor, and then using optics with a big enough aperture to spread the image over the sensor is what does it. Complicating things by using only part of the sensor, and rapidly altering the addressing to counter camera shake, or addressing only a bit in the middle to have "electronic zoom", and averaging sites to make single lower noise "new pixel" all cannot get around the fundamental physics of what is "resolution". Resolution is the number of line pairs/mm of bright to dark transition to an agreed level. It quite hard to do. If it gets close to the pixel spacing, you get interference patterning.
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