Photographers Are Collateral Damage in the Ongoing Pixel War

Is it foolish to buy a 40-plus megapixel camera? Does it make any difference to your prints? Here are further reasons why it may be a false wish.

Camera manufacturers are still pushing ever higher megapixel counts. For years, the big manufacturers have fought over ever more pixels. As I pointed out in my last article, those bigger pictures can be disadvantageous for us photographers.

Even if the big file sizes are not a hindrance, many photographers may see no benefit in upgrading. Many of us don’t need all the 40- or 60-megapixel resolution some modern cameras deliver. But what about printing our images? Surely more pixels are better, right?

Separating Pixels, Points, and Dots

To understand how pixels affect your images, you must get to grips with a few terms.

Firstly, the absolute resolution of an image is the number of tiny dots (pixels) it contains. It’s the number of pixels across the photo (width) multiplied by those up the photo (height). So, if your image is 6000 x 4000 pixels, that means it is 6000 pixels wide and 4000 pixels tall, for a total of 24 million pixels (24 megapixels). It’s a fixed size. Unless you have cropped your picture, the absolute resolution is equal to your camera’s megapixel value.

Although that remains constant, print sizes can vary.

To help aid understanding, I am going to change a term slightly. A print comprises millions of tiny ink points. (These points are properly called pixels too, but I am going to use “points” to differentiate them from the pixels in an image.) We can change the number of those points in every inch of the print. For photo quality, we set the points to 300 per inch of print; i.e., 300 points per inch (PPI). At a lower resolution, say 150 PPI, there are 150 points per inch, so each point needs to be larger; otherwise, there would be gaps between them.

Consequently, if we print the same image at those two resolutions, the second print would have four times the area. However, a closer examination of the second image with a magnifying glass might reveal less fine detail.

It’s worth noting that PPI differs from Dots Per Inch (DPI). Printers usually use multiple dots to reproduce one point. Consequently, DPI numbers are usually much higher than PPI values. So DPI refers to how many of those even tinier ink dots the printer places on paper. The printer driver handles that. You may see, for example, 600, 1200, and 2400 DPI in the printer settings. Increasing the DPI does not change the detail in your image file. However, it lets the printer place more ink dots per inch, making lines, text, and image details crisper. That is especially noticeable in photos. Higher DPIs also result in smoother gradients and tones, better color blending, and reduced visible banding. Therefore, the photo will have smoother shadows, highlights, and color transitions. It also improves color accuracy, helping them to look closer to what you see on your screen. But DPI does not change the overall resolution.

Stand Back to View Large Photos

If you want to print a 6000 x 4000 pixel picture at photo quality (300 PPI), at 100% resolution, it will have a width of (6000 ÷ 300) 20 inches (50 cm) and a height of (4000 ÷ 300) 13.33 inches (33.86 cm).

If we were to print it much larger as a wall poster, we could use a lower print resolution since we view it from farther back. Therefore, at 150 PPI, the maximum width would be (6000 ÷ 150) 40 inches (101.6cm) and the height would be (4000 ÷ 150) 26.67 inches (67.7 cm).

My camera, the OM-1 Mark II, has a 20.4-megapixel sensor, more than enough to print at A3. I could print an A3 80MP picture, and there would be no difference in image detail.

For an A2 print, the resolution doubles again to 34.8 megapixels. In theory, that is more than my camera can handle, unless I use its magic trick of shifting the sensor between shots and compositing the series into a single 80MP image.

That technology notwithstanding, there is a plethora of software available that will upscale smaller photos for larger prints. Historically, programs used fractals to do that, but now it is carried out by AI. That creates new detail between the existing pixels. The AI models are trained on millions of real pairs of low- and high-resolution images. They then predict missing pixels based on learned visual patterns rather than on the mathematical similarity of the past.

My preferred tool for doing that is the Resize AI tool included in ON-1 Photo Raw, which I use all the time when restoring old photos I have scanned. Others use Topaz Gigapixel AI, which also works well. Adobe Camera Raw and Lightroom include a “Super Resolution” tool that upscales by a factor of 2 in each dimension, making the image four times larger. However, it is more limited in its ability to scale as it cannot synthesize creative detail.

Stand Back

When we look at a painting, we are not usually examining every finest brush stroke. Instead, we are standing back to appreciate the entire picture. The same applies to photos. An A3 image is best viewed standing around 1.1 meters (43 inches) away, so we can see the entire frame. At that distance, if we have 20/20 vision, we can resolve details down to 0.32mm. At 300 PPI, the ink points are only 0.0847 mm, which is over three times smaller than what we can see.

Meanwhile, to best view an A2 image, one should stand 1.4 meters (55 inches) back from it. At that distance, our eyes can only resolve to 0.4 mm.

In other words, the bigger the print, the farther the optimum viewing distance. From farther back, we can’t see the individual pixels even if they are larger. Therefore, it usually makes no real sense to use 300 PPI on a huge print. At 240 PPI, the ink points are 0.106 millimeters, which is still far too small to see at the optimal viewing distance. So, my 20.4 MP camera can produce A2 prints for normal viewing without upscaling.

Of course, there are exceptions to every rule, and there may be some extreme technical instances where a photographer wants the viewer to breathe their spittle onto the print to see the finest detail, rather than viewing the entire picture from the optimum distance.

Furthermore, billboard prints use very low effective DPI. They still look sharp from a distance. If you think back to the early 2000s, the Canon 1D had a 4-megapixel sensor that produced perfectly good images for billboard advertisements.

 How Far Can We Zoom in on an Image on a Screen?

Let’s translate that to what you see on the screen. Remember that the image’s absolute resolution remains the same. If your screen were also 6000 dots wide and 4000 dots high, that image would fit on the screen perfectly at 100%. However, most screens don’t have anything like resolution.

Most photographers still use a Full High Definition (FHD) screen, which is 1920 pixels across and 1080 pixels high. That is 2,073,600 pixels. Even a 4K Ultra High Definition (UHD) screen is only 3840 pixels wide by 2160 pixels tall, for a total of 8,510,400 pixels. That is far fewer than my 20.4-megapixel camera.

Also, screens come in many different sizes. On laptops, the screen size is most commonly 14″ to 15.6″ diagonally from corner to corner. Meanwhile, desktop monitors are larger. Many are still happy with two 24″ monitors, although 27″ and even 32″ 4K screens are becoming common.

However, like prints, those bigger screens also need to be set farther back. Ideally, a 24″ monitor will be 50–75 cm (20–30 in) from the viewer. Meanwhile, a 27″ monitor should be 60–80 cm (24–32 in) away, and a 32″ monitor set back 80–110 cm (32–43 in).

FHD and UHD displays don’t change their pixel count, regardless of screen size. Therefore, if you have a high-resolution image, it will be resized downwards to fit the screen. At 100% zoom, the subject will appear smaller on a 4K screen than on an FHD screen. It squashed more screen pixels into a smaller area. Therefore, the image appears smaller. That, of course, makes it harder to do precise masking and editing of fine detail. There’s always a disadvantage.

Incidentally, the same applies to TVs. Many people buy enormous screen TVs and end up sitting too close, so they cannot take in the entire scene. Bigger isn’t always better.

So, don’t feel pressured to buy a bigger screen with higher resolution.

In Conclusion

As I have shown in this and the previous article, you do not necessarily need more pixels in your camera or on your screen. Nevertheless, there is considerable peer and marketing pressure to upgrade our cameras and our screens. Because of that, we sometimes get misled into thinking that upgrading is the right thing to do. Of course, there are occasional exceptions where ultra high definition is necessary. Nevertheless, for most photographers, we have reached a saturation point where we don’t really need more. What your camera delivers is probably enough, so be at peace with it. You don’t need to become collateral damage in a pixel war you don’t want.