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 (...
51
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 ...
33
According to Ken Rockwell:
Fuji Velvia 50 is rated to resolve 160 lines per millimeter. This is the finest level of detail it can resolve, at which point its MTF just about hits zero.
Each line will require one light and one dark pixel, or two pixels. Thus it will take about 320 pixels per millimeter to represent what's on Velvia 50.
320 pixels x 320 pixels ...
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
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 ...
26
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 ...
24
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 ...
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 ...
20
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
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 = ...
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
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 ...
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.
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
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 ...
11
Short answer: no. Especially not in the case of facebook, where you explicitely give them the right to use your images almost as they want. From their terms:
Specifically, when you share, post, or upload content that is covered by intellectual property rights (like photos or videos) on or in connection with our Products, you grant us a non-exclusive, ...
10
The "are you allowed" question is really up to Amazon; from the specs you've given, the answer seems to be "yes", and in fact from a pure megapixels view, by a long shot. 200×200 pixels is less than 1% of a megapixel, and you have 13 megapixels to work with.
But then you ask a perplexing question about "highest quality allowed". If by "quality" you simply ...
10
Megapixels just tell you one thing: the number of individual tiny detectors on the sensor. They do not tell you anything about:
the size of the sensor overall
the sensitivity and size of each sensor
the ability to read from the sensor without introducing noise
other technical aspects of the sensor construction (back side illuminated? standard Bayer array or ...
10
This is not only possible, but extremely likely, when you're using a compressed image format such as JPEG. Data compression methods in general become more efficient as the data to be compressed decreases in entropy (try creating zip files of a large page of actual text vs. the same sized page of a single repeated character).
The more features or fine ...
10
Quoting from DPReview's spec sheet for the 1D X Mark II:
Continuous drive 16.0 fps
That means that the 1D X Mark II is pushing 20 MP × 16 = 320 MP through its pipeline every second, which is a bigger number than you'll find on any of Canon's other models; for example, the 5DS R has only 5 FPS. 20 MP is good enough for the intended market of the 1D X ...
10
Imagine yourself at the side line of a major sports event. Yeah it's bloody dark despite the stadium lights and you cannot send in your assistant to chase the athletes with a flash. You'd rather have only 20MP but decent low light performance, because more pixels means smaller pixels means less photons per pixel.
9
Let me start by saying that the term "true resolution" has no set meaning. It is a term that Snapsort uses to try and simplify the meaningful detail a camera can capture.
Resolution, at its most basic, is the level of granularity of detail that a camera can capture. You could have a 200 mega pixel camera, but if the image was out of focus and you only ...
9
Theoretically, most image formats could be downscaled progressively, without loading the entire image into memory, however I do not know any tools that really implement such feature, except for JPEG: it is special in that you can not only downscale without loading full resolution, but also downscale without decoding full resolution, thanks to the creative ...
9
There is no hard limit to resolution - details don't just vanish they fade out gradually as the contrast between light and dark is reduced. This reduction in contrast is expressed by means of the modulation transfer function (MTF). It's just a fancy way of saying details of size X will experience a loss of contrast Y.
The MTF of a camera system is the ...
9
When shooting JPEG you usually have to option to select the size and quality of your image. For instance with Nikon cameras you can select Large and Fine. This option will give you the maximum resolution. This is also the resolution of the RAW file so you will not gain any resolution if you shooting at the maximum JPEG quality. Shooting RAW will give you ...
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