User:Colin/PixelPeeping

The pejorative term "pixel peeping" (or "pixel peeper") was coined by the late Michael Reichmann in 2003.

Unfortunately there are some folks who see a bit of noise texture in a 100% crop and somehow jump to the conclusion that the image is crap. It shouldn’t be necessary to point this out, but if the entire image were shown it would be equivalent to an on-screen image almost 3 feet high by 4 feet wide. Of course you’re going to see some noise and other artifacts. But the important thing to keep in mind is how does it look in a typical sized print — say up to 11X17" image size on paper?

Here’s the thing that the pixel peepers don’t get. My testing has shown that photographs produced by this camera can be of professional grade — suitable for stock use, professional publication and fine-art exhibition. The fact that it is somewhat noisier than other cameras at any given ISO, and that there is some occasional CA really has little to do with its usefulness as a photographic tool.

— Michael Reichmann, Luminous Landscapes Sony 828 Review 2003.[1]

Viewing photos

Michael Reichmann is concerned how the whole image will look when viewed typically, not how a crop of the image will look when viewed at close range on a 100 DPI monitor. How should we, as image reviewers, approach this concern? Digital displays and prints on paper remain the two main media for photographic still images, though things have changed somewhat since 2003. Digital viewing vastly outweighs printed media and such viewing has shifted from desktop to mobile devices.

The following tables describe the current state of print and digital display formats and camera sensors. If we ignore any artistic cropping, an 18 megapixel camera should satisfy nearly all commercial still-image work. Such images will fill a page spread in a glossy magazine or the display of even the highest resolution consumer computer displays currently available. They can also easily fill a poster in a bus shelter or billboard.

For video formats, an HD video requires only a 2.5 megapixel camera, and a 4K UHD video requires only a 10 megapixel camera. The future 8K video standard will need a 40 megapixel DSLR!

Most DSLRs have a resolution around 24 megapixels today, which represents only a doubling of linear resolution since the early 6MP cameras. While camera sensor linear resolution has doubled, it has taken longer for desktop display DPI to double, remaining stuck around 100 DPI. Although current displays are higher resolution, they have also got bigger. When viewed at 100% a 24MP image is magnified 2 x compared to a 6MP image. At 100 DPI a desktop display is also magnified 3 x compared to high quality print. This makes pixel-level defects more visible, but the 24MP image is not twice as bad as the 6MP image. It is superior in every way, except to a pixel peeper.

Image types

• Bold subjects
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• Detailed subjects
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In the above galleries, I've grouped images into two sets. The "bold subjects" are those that work well at any size and don't reward high magnification other than to satisfy oneself that the image is indeed detailed and sharp. If you've got the image full screen on your display, you don't feel a strong urge to zoom in any further. The "detailed subjects", on the other had, are asking for you to zoom in. When you do, you can see the fretwork on the organ at the Royal Albert Hall, the faces of the disciples in Viborg cathedral, the text on the stained glass window in St Matthew's Church, or the finely painted figures in winter landscape. Perhaps, in order to determine what degree of magnification is fair in which to judge small defects, we should consider what degree of magnification the subject encourages of the viewer.

Media

The standard for high quality printing is 300 DPI for work that is viewed at close range. Images that are viewed from a distance, such as a poster, only require a considerably lower DPI. A DSLR takes an image of 3:2 aspect ratio. Computer monitors typically have a display around 100 DPI, though the newer High DPI 4K and 5K displays are around 200 DPI and an 8K display exceeds the 300DPI resolution of print.

Print

The page dimensions are those given by the publisher for submitted images, which include bleed that is cropped to fit the final page size.

Medium	Page Dimensions	Page Dimensions px	Page Megapixels	3:2 Camera Image px	3:2 Camera Megapixels
Snapshot	6" × 4" 15 × 10 cm	1800 × 1200	2.1	1800 × 1200	2.1
Portrait	8" × 10" 20 × 25 cm	2400 × 3000	7.2	2400 × 3600	8.6
National Geographic Full Page	7 1/8" × 10 1/4" 181 × 260 mm	2138 × 3075	6.6	2138 × 3207	6.9
National Geographic Spread	14" × 10 1/4" 356 × 260 mm	4200 × 3075	12.9	4613 × 3075	14.2
Vogue Full Page	8 1/4" × 11 1/8" 210 × 283 mm	2475 × 3338	8.3	2475 × 3713	9.2
Vogue Spread	16 1/4" × 11 1/8" 413 × 283 mm	4875 × 3338	16.3	5007 × 3338	16.7

Desktop

Display	16:9 Display Resolution	16:9 Display Megapixels	DPI	3:2 Camera Image px	3:2 Camera Megapixels
23.8" Full HD	1920 × 1080	2.1	93	1920 × 1280	2.5
27" QHD	2560 × 1440	3.7	109	2560 × 1707	4.4
23.8" 4K UHD	3840 × 2160	8.3	185	3840 × 2560	9.8
27" 5K	5120 × 2880	14.7	218	5120 × 3413	17.5
27" 8K	7680 × 4320	33.2	326	7680 × 5120	39.3

Mobile Phone

Display	Size	16:9 Display Resolution	16:9 Display Megapixels	DPI	3:2 Camera Image px	3:2 Camera Megapixels
Apple iPhone 4	3.5"	640 × 960	0.6	326	640 × 960	0.6
Apple iPhone 5	4"	640 × 1136	0.7	326	757 × 1136	0.9
Apple iPhone 6 Plus	5.5"	1080 × 1920	2.1	401	1280 × 1920	2.5
LG G4	5.5"	1440 × 2560	3.7	538	1707 × 2560	4.4
Samsung Galaxy S7	5.1"	1440 × 2560	3.7	576	1707 × 2560	4.4
Sony Xperia Z5 Premium	5.5"	2160 × 3840	8.3	801	2560 × 3840	9.8

Mobile Tablet

Display	Size	16:9 Display Resolution	16:9 Display Megapixels	DPI	3:2 Camera Image px	3:2 Camera Megapixels
Apple iPad 1 & 2	9.7″	1024 × 768	0.8	132	1152 × 768	0.9
Apple iPad 3	9.7″	2048 × 1536	3.1	264	2304× 1536	3.5
Apple iPad mini retina	7.9"	2048 × 1536	3.1	324	2304 × 1536	3.5
Apple iPad Pro	12.9"	2732 × 2048	5.6	264	3072 × 2048	6.3

Cameras

The sensor-area resolution of cameras in megapixels increased rapidly and almost yearly till 2015. However the increase in linear resolution is more gradual. To double the linear resolution, a bigger jump is required of area:

•  4MP → 16MP
•  6MP → 24MP
•  8MP → 36MP
• 10MP → 42MP
• 12MP → 51MP

Model	Year	Megapixels	Image Width	Image Height	Linear Increase
Nikon D1	1999	3	2000	1316	-48%
Nikon D2H	2003	4	2464	1632	-36%
Nikon D70	2004	6	3008	2000	-22%
Canon EOS-20D	2004	8	3504	2336	-10%
Sony A100	2006	10	3872	2592	0%
Sony A700	2007	12	4288	2856	11%
Sony A350	2008	14	4592	3056	19%
Sony A55	2010	16	4912	3264	27%
Canon EOS-7D	2009	18	5184	3456	34%
Sony A77	2011	24	6000	4000	55%
Sony A7R	2013	36	7360	4912	90%
Sony A7RII	2015	42	7952	5304	105%
Canon 5DS	2015	51	8688	5792	124%