100

4K might be the next big thing in video, but for still photography that's just 8 megapixels, which is quite low for most cameras, and I think around the resolution of the iPhone. I have a Nikon D5300 with 24MP resolution, and I've seen other DSLRs get up to 36MP or higher. And no matter what, if you zoom in enough, you will eventually get pixelation (...


47

You ask if there is a practical difference. So the answer is yes, albeit a very small one, but some of the other answers have missed it. You're right that the only difference is in the metadata: if you save the same image as 300dpi and 72dpi the pixels are exactly the same, only the EXIF data embedded in the image file is different. (I've even verified this ...


46

Most cameras already have a resolution going far beyond 4K. Assuming you mean Ultra HD (3840x2160) opposed to "true" DCI 4K (4096x2160) you get a resolution of about 8MP (DCI 4K would be about 8.8MP). Most cameras are already way over this size and are at 20MP or even higher. So a "4K" image would actually be smaller than a full size image. That aside, you ...


46

All pixels are not equal Larger pixel wells, such as those found on a 20MP full frame sensor, are able to capture more photons than smaller pixels like those on a high resolution phone sensor. The pixel pitch for the EOS 1D X Mark II is 6.6µm. The pixel pitch for the Samsung Galaxy S5 is 1.12µm. That means that in terms of surface area the pixels in the 1D X ...


29

I used ImageMagick on Ubuntu to resize those big pictures. convert -resize 10% source.jpg dest.jpg It took awhile, but worked with 1 GByte of RAM, the tool created a 4.7 Gbyte swap-like file for itself. More information is on AskUbuntu.


28

Question about thing like frame rate, resolution or dynamic range of the human eye and how they compare to cameras always have the same problems: The "picture" you see isn't a "single exposure", the eye is constantly moving and adjusting. The part of tee brain that handles vision is really good (and pretty big), it constantly combines the "frames" is gets ...


28

Compromises are made in everything. Look a little harder and you can find "top" DSLRs with many, many more pixels. Hasselblad H6D-100c has 100 MP, for example. But looking at only megapixels gives you a very incomplete picture of what the camera can do. Directly tied to resolution is throughput: shooting a 20 megapixel image at 16 frames per second = 320 MP ...


25

one of my Facebook accounts seem to have lost a significant amount of resolution Facebook (and other social media sites) compress photos while storing/displaying. Considering the amount of data that gets uploaded in these sites, its difficult to argue against it. This link talks about how you can minimize that to a small extent (but that article is old and ...


23

No. Aliasing is result of sampling, taking discrete samples or readings of a signal, at a low enough frequency that the frequencies in the input signal are confused for other frequencies, such that they cannot be distinguished from each other. If film grain were aligned with regularity, their spatial frequency would create opportunities for aliasing, just ...


21

I'm going to sort of disagree with all the other answers that talk about DPI or PPI rules of thumb, and suggest two different 'rules' (based on PPD, from another answer of mine) Rule 1 — The 'Retina' rule (aka the Pixels-Per-Degree (PPD) / 'better than your eye can see' rule) This comes pretty much straight from Apple's Retina display designs, the idea ...


19

Spatial resolution in Remote Sensing is normally expressed in distance per sample rather than samples per unit distance. The same information is there, it's just expressed as the reciprocal of what is usual in normal graphics fields. The "per sample/pixel/whatever" is normally dropped as well and as it is considered implicit. So a resolution of 0.5 m is ...


18

File size, quality, resolution - pick any two. If you had images in an uncompressed format like BMP, then you could make them a bit smaller without sacrificing any quality or resolution by saving them in a compressed format that doesn't do lossy compression, like PNG-24. JPEG images are already compressed, so with the given quality and resultion they are ...


18

Whoever told you about 4K probably mislead you. At least, you have the resolution right. You see, 4K at 3840x2160 is a resolution term used for video, signifying almost 4000 pixels in width. The aspect ratio there is 16:9 which is the same as HD video. Cameras usually shoot 4:3 or 3:2 images, although there are other ratios too. A pixel is a pixel. There is ...


18

This is in the Exif standard for metadata, on page 26: ResolutionUnit The unit for measuring XResolution and YResolution. The same unit is used for both XResolution and YResolution. If the image resolution in unknown, 2 (inches) is designated. Tag = 296 (128.H) Type = ...


17

Ironically, I just did the math for this in another thread. Image quality is a convolution of all imaging system factors. The resolution of the lens or the resolution of the sensor are not independent factors...they are factors that convolve to produce the final "system resolution". If we use your two cameras as examples, we can calculate the resolutions of ...


17

If the resolution long axis is at least 1920 and the short edge at least 1080 then yes, you can take HD images without having to upscale. However, due to benefits of oversampling, you will make a better HD image by grabbing a 16MP image and then resize with the best available resize method, e.g. lanczos interpolation if available. Another problem you may ...


16

Bear with me for a second here for some background.... When you downsample a 4000×3000 image to 400×300, you are "discarding" 11.9 million of the 12 million pixels. This clearly reduces "image quality", depending on what exactly you mean by that term. If you go from 1000×750 to 400×300, you're reducing the area by about 6 times. Again, data is discarded, ...


15

Does an image edited and saved/exported with 1200x800 pixels at 300 ppi look any different online than the same image saved/exported with 1200x800 pixels at 72 ppi? No. A bitmap produced either on-screen or on paper from the image will be identical. The only difference would be the default print size from some applications, and only then if the image size ...


14

No, you cannot say it has infinite resolution, despite what CSI may have people believe :) A film particle puts limits on how fine details can be resolved. It gets complicated though because film has grains of different sizes. Every frame is composed of grains of different sises and they are intermixed. Larger particles are more sensitive to light and used ...


14

The image I uploaded was rejected because it was under 300 DPI. The DPI is just a number which has no relevance to a digital image. It relates only to printing and not the quality or resolution of the image itself. If you change the number to 300 DPI in an editor, it should be accepted. As you have Windows 10 and presumably use assistive technology to e....


13

I have found the free waifu2x very good for upsizing images. You can try an online demo. It uses "Deep Convolutional Neural Networks" to predict what the missing image data should be. It works better for line art, but is definitely acceptable for photos.


13

The first two images both have embedded color profiles. The smaller one has Adobe RGB, and the larger one has "TIFF RGB", which happens to consume more space. My guess is you probably want these to be sRGB anyway, with no embedded color profile. In the second case, it's the details. The hand photograph has big areas of the same color, a lot of blur, and ...


13

No, because of the Bayer filter. You would actually need around 11 megapixels. What a Bayer filter is Colour camera sensors use Bayer filters to capture the various colours. The Bayer filter effectively halves the resolution of the sensor for each colour (though green is left with slightly more in a checker-board pattern). Each pixel on the sensor can ...


13

If you look at the specifications of the human eye as if it's a camera, you're going to find it's pretty low-specced. Very low resolution in terms of pixels - very few megapixels - with most pixels concentrated in a very small area in the centre. Virtually no ability to distinguish fine detail outside of a small area in the centre of the frame. Horrible ...


12

You are right that a 1080p HD image has just under 2 megapixels. Now where you have to be careful is in considering the aspect ratio of your camera. If it shoots natively 16:9 images and it has 2 MP, then you would have enough resolution. If the camera has a 4:3 sensor which is the most common for small cameras, a 2 MP camera would most likely capture a ...


12

There are a lot more to image quality than resolution (i.e. number of megapixel). First of the light from the subject has to be gathered to the image sensor. This is done by one or several optical elements that together constitutes the lens. These elements can differ in quality and a low quality lens will not produce a high quality image no matter the ...


12

"Resolution: <whatever>" means that the image contains sufficient detail to resolve an object of size <whatever> on the ground. There are multiple definitions of exactly what it means to be able to "resolve an object" of a given size, but basically it means that you will be able to distinguish objects that far apart, but not if they're closer. For ...


11

The same way that we can make an HDTV the same size as an old low res TV or even smaller. We make the pixels on the sensor smaller. The sensor size (APS-C, full frame, etc) refers to the size of the area that the light is focused on to. It can be very large in the case of research telescope sensors and digital medium format cameras or very small in the ...


11

Note that you can crop JPEG images without having to reencode them if you use tools that work with the JPEG format, such as jpegcrops, jpegcrop, or jpegtran - these tools perform lossless operations on JPEG files, including cropping, concatenation, and certain transformations (e.g. 90-degree rotation) by working with the underlying DCT data (as opposed to ...


10

This is kind of an ongoing debate, and it depends on what your goals are and how you edit your photos. I think that the naysayer argument, which I'll get into, can be considered kind of moot as you can compensate, and as such I am a strong believer in getting the highest density screen you can get your hands on. This debate as increasing merit as more and ...


Only top voted, non community-wiki answers of a minimum length are eligible