Photography / Tips and Solutions

The Pixel Wars are Back, and That's Great!

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When the megapixel counts started to stabilize at about 24MP, many of us thought the days of constant one-upmanship in camera resolution was just about over. Well, apparently, they were just on a break because, in the past few years, we have seen the release of multiple cameras starting to expand to more than 40 megapixels. Beyond this, a few manufacturers are using multi-shot modes to create images of even greater resolutions. While many may bemoan this with the potential for added noise in low light and sluggish computers, I’m excited to see what is going to happen next, and you should be, too.

The obvious reason to be happy about the latest high-megapixel sensors is simply that companies are still developing new sensors with higher resolution. With retina displays and 4K TVs now commonplace, our imaging tools are going to have to produce consistently higher-resolution content to match. We also know that down-sampling or cropping to native resolution is a better practice than up-scaling later or even shooting exactly to the proper size. Part of the reason that down-sampling is a successful practice is because of how modern image sensors work. They rely on arrays of red, green, and blue pixels, usually in a Bayer pattern, and then interpolate the color and luminance information to create a final image. In practice, this means that you are not leveraging the full resolution of the sensor, since some data is not captured—it is created.

Now, some sensors, like Sigma’s Foveon, will capture full resolution and color information at each pixel. Or, you can go with a monochrome-only sensor, such as Leica’s M Monochrom, for added resolution, but the rest of us will have to settle for slightly less detail and the potential for moiré. Down-sampling helps solve this dilemma by consolidating the information even more, basically taking the interpolated data and shrinking it down, making it produce a seemingly sharper final image. Some manufacturers do have some tricks for getting around this limitation by using multiple images to create a single full-data photograph.

Sigma sd Quattro H Mirrorless Digital Camera

Multi-shot, pixel shift, and other proprietary modes pioneered in recent years all take advantage of sensor-shift mechanisms to capture as much data as possible. Hasselblad is the king of this field, with its insane H6D-400c MS, which can create 400MP images using a six-shot burst. By precisely moving the sensor in pixel-length increments and smaller, the H6D will capture full RGB data for each picture, as well as additional detail to create a 400MP final shot without the disadvantages or cost associated with a true 400MP sensor. Now, the price of the Hasselblad is likely a bit too steep for the average photographer. Fortunately, Panasonic, Olympus, Sony, and others have stepped in with their own technology. These can create more modest 50-80MP and greater images with ease, so you shouldn’t be worried about whether your images will hold up on next year’s super retina displays.

Hasselblad H6D-400c MS Medium Format DSLR Camera

Another benefit to high-res sensors is the ability to crop in with ease and still retain detail while taking advantage of in-camera cropping to “zoom” in on your subject without switching lenses. This is obviously not best practice, since you aren’t taking full advantage of your camera’s format or the lens, but there are some positives, especially if you are shooting sports or action and need a quick turnaround. By quickly getting into a crop mode, you can compose your final images more easily and enjoy a nearly ready-to-go photo right after taking the shot. And, it quickly turns your 70-200mm zoom into a more impressive 105-300mm without the added cost or weight.

Coming as a bonus to crop modes is that many auto-focus systems perform best in the center of the frame and, by cropping in, you are using the sweet spot of the AF system. However, back with 10- and 12MP sensors, cropping in would’ve resulted in a significant loss of detail, but with something like the a7R III’s 42MP sensor, you can get a very usable 18MP still from an APS-C frame. Add an electronic viewfinder to the equation and you have a full-size image in your vision for easier composition, as well—no more guessing with an optical finder, although some manufacturers have figured out how to help with optical finders by darkening areas that are outside the current aspect ratio or crop setting. In any of these cases, it provides another tool for photographers who need a little more versatility. A side note to this is that video shooters can also benefit in the same way, because you can switch quickly from full frame to Super35 to potentially even smaller, without giving up a native 4K image.

Sony Alpha a7R III Mirrorless Digital Camera

If you print, or want to print, added resolution is an obvious benefit if you want to go large. Ideally, you are going to want to keep 300 dpi resolution when you print, to maximize the detail in your image. And if you look at a standard 24MP sensor with a 6000 x 4000-pixel output, that only lets you reach a little larger than a 13 x 19" print while retaining optimal resolution. Now, if you go up to the 46MP sensor of the Nikon D850, with its 8256 x 5504 output, you can easily create a 17 x 22" print with room to spare. To be fair, it isn’t uncommon to use up-scaling to create phenomenal 30 x 40" and larger prints from smaller-resolution images, and most of the time it is just fine. However, if you really want to start looking big, or you happen to rely on cropping in your post-production workflow, starting with more pixels is for the best.

Nikon D850 DSLR Camera

As for the final reason to be happy about the continued push to higher and higher megapixel counts is simply that technology is getting better and better. I remember going out with a Canon 10D, a 6.3MP DSLR, and being afraid to go up to ISO 800 since noise was such an issue. Now I can pick up a Canon 5DS R with 50MP resolution and shoot at up to ISO 6400 and still have something very usable. While engineers are figuring out how to cram more pixels onto the sensor, they are also making each pixel better, whether that is by redesigning the micro lenses to capture more light, using back-illuminated architecture, or simply using better processing to ensure cleaner imagery. As resolutions increase, you can be certain that other aspects of digital imaging will get better as well.

Canon EOS 5DS R DSLR Camera

Are you excited for even higher resolution cameras to be released? Or would you prefer more modest megapixel counts in your next DSLR or mirrorless system? Join the conversation in the Comments section, below!

6 Comments

That is a bit deceptive.  As far as I know no common APS-C sensor has more than 24.3MP as of February, 2018.  Yes, the FF (FX) Nikon D850 has 45MP, and there was a Canon 5D submodel with 40+.  The ones with 80MP are medium format digital cameras.  The pixel density of a APS-C 24.3MP sensor is the highest.  For a Full Frame to equal that it would have to have 54MP.  And as others have said diffraction limitations become significant above the 16MP / 36MP  (DX/FX) range.  Physics does not allow a free lunch.  I'd more like to see research put into more non-beyer array sensors and cameras with more native dynamic range like film with out reverting to HDR games.  Why aren't all cameras a full 16-bit by now?

Michael W. wrote:

...no common APS-C sensor has more than 24.3MP as of February, 2018...

Samsung NX-1 had 28mp as of September 2014... With "...Outstanding dynamic range and low light image quality..." per DPReview.

Great article. I have to admire the advances in sensor technology since my first digital camera (Canon A70 3mp). My cell phone now has more MP that that camera. Once the digital bug bit hard, I sold off my Leica M and Nikon film kits and went with Nikon digital. (Should have kept the Leitz glass in retrospect)

Yet, I still don't have any need for a 40+mp camera. I moved from a Nikon D300 to the Fuji X system a few years ago and find that a 24mp APS-C sensor meets MY needs. Then again, I prefer to "crop in camera" and the 1.5x factor rarely requires me to crop an image on screen. I also rarely shoot beyond ISO 800 which my X-Pro2 handles with ease. I know that to some folks, higher ISO settings are very important. But, again, I personally don't have the need. "Horses for courses" and all that.

Matthew makes a good point about lenses being the limiting factor these days. That said, I go back to the days when zoom lenses were anathema to most of us. Today, I don't think twice of picking up a high-end zoom as the difference between zooms and primes have narrowed immensely. Zoom or prime, I still try to stay below the aperture where diffraction comes into play unless I'm looking for something like a "star" effect.

I'll never say "never". I'd be lying if I said that I would never buy, for example, a Nikon D850 or the equivalent from Canon, Sony or whoever. But, for now, I'm more than satisfied with 24mp and APS-C. Hopefully, the designers will keep pushing the envelope as the advances tend to trickle down to those of us who don't need the top-of-the-line stuff.

This is all technologically wonderful, but in many cases it doesn't help because the lens limits the resolution, not the camera body.  The inescapable diffraction blur (the Airy disk) is larger than the pixel sizes a lot of sensors use, and thus is the limiting factor in resolution.

Also, many of the high-pixel-count sensors use smaller pixel sizes, collect fewer photons, and are more susceptible to Poisson-type noise. So while technically the resolution might go up, the rise in noise precludes improved image quality (a value judgment based on personal sensitivity to noise in the image, and thus subject to endless argument :-)  To some degree, backside-illuminated sensors, and those with higher quantum efficiency and lower dark currents, will negate some of the noise increase. However, the number of photons actually turned into electrical signal is still a very important variable.

In sum, don't be all that impressed with super-high megapixel numbers. It's the image quality that is important, not "bare resolution" based on pixel count alone. Pixel size, sensor manufacturing quality, sensor readout circuit noise, lens quality and f/number are all involved. 

Thanks for the response Matthew! Everything you are saying is accurate, and I agree much of the time (it's why until recently I had both an a7S II and a7R II at my disposal, different tools for different jobs). But when I'm working in a studio with monolights its hard to deny the appeal of using a 50MP camera and looking at the detail available in that final image. But, all of the subjects you bring up are important, and its why an article on the other side of the argument is currently in the works, so stay tuned!

That's why I ended up choosing an A7RII, now A7RIII. With the BSI sensor, it has excellent high ISO performance and dynamic range. I would've preferred to stay with 24MP, but 42 grew on me, giving me the choice to downsample after reducing the noise and retaining lots of details, or carry along a single sharp wide angle prime and crop it almost as much as I want. In the end, I really enjoy having more megapixels, but 42 is definitely enough, I wouldn't want more (unless it provided me with even better high ISO performance and dynamic range).

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