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222 votes
Accepted

What does an unprocessed RAW file look like?

There is a tool called dcraw which reads various RAW file types and extracts pixel data from them — it's actually the original code at the very bottom of a lot of open source and even commercial RAW ...
mattdm's user avatar
  • 143k
67 votes

Given an image how to identify whether it is RAW file or not

Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not? If you have a JPEG file, then it is not a RAW file. RAW isn't a single format, but rather a collective ...
Caleb's user avatar
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47 votes

Why do we use RGB instead of wavelengths to represent colours?

The goal of the imaging engineer has always been to capture with the camera a faithful image of the outside world and present that image in such a way that the observer sees true to life picture. This ...
Alan Marcus's user avatar
  • 39.2k
36 votes

Why do we use RGB instead of wavelengths to represent colours?

You said, this is the information that is captured at first by digital cameras. That is not correct. By themselves, sensors on most digital cameras respond to a broad band of frequencies of light, ...
scottbb's user avatar
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35 votes
Accepted

Changing JPEG to RAW to use on Lightroom?

In my opinion, none of the other answers addresses the obvious misconception in the question: There is no use in converting a JPG (comparatively low quality) to a RAW file (high quality), because you ...
Ian's user avatar
  • 446
33 votes

Can you "open" RAW camera files?

It's linguistics. Of course you can open a raw file, as the term "to open a file" has a very broad spectrum of different, but related meanings. On a low level, "to open" just ...
Ralf Kleberhoff's user avatar
27 votes

Do raw images of the same camera have the same size?

Many digital cameras use lossless compression with raw files. That means the size of raw files from the same camera is somewhat content dependent. The more detail and different colors a scene ...
Michael C's user avatar
  • 175k
27 votes

Do raw images of the same camera have the same size?

A picture being worth a thousand spreadsheet cells, here is an histogram of the size of the RAW files from my camera for 2018 (EOS 70D, 20Mpx). Sizes are in 1000's of K (not really MB). For the ...
xenoid's user avatar
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24 votes
Accepted

RAW files store 3 colors per pixel, or only one?

Raw files don't really store any colors per pixel. They only store a single brightness value per pixel. It is true that with a Bayer mask over each pixel the light is filtered with either a Red, Green,...
Michael C's user avatar
  • 175k
23 votes

Given an image how to identify whether it is RAW file or not

Unless somebody frivolously renamed a RAW file, it will never have a file name with the .jpg/.jpeg/.jfif extension. Typical extensions for RAW files will be .raw, .arw (Sony), .dng (Android phones etc....
rackandboneman's user avatar
23 votes

Is it normal for RAW files to have lens distortion? How best to deal with it?

Is this normal for RAW images? Yes, it is normal. Based on my experience with Canon cameras with different lenses, the RAW image remains uncorrected w.r.t. to the corresponding JPEG. This means that ...
Saaru Lindestøkke's user avatar
19 votes

Changing JPEG to RAW to use on Lightroom?

In the absence of real raw files, the JPG is your "raw". Most image editors, including Lightroom, can open or import JPGs. You may choose to save in another format while editing, but do not lose or ...
xiota's user avatar
  • 27k
18 votes

While shooting in RAW, do you have to post-process it to make the picture look good?

From what I understand of your question, you're asking whether a Straight Out Of Camera (SOOC) RAW file should be edited to look "good". The short answer is "Yes, it should go through post-processing"...
Hurst Gannon's user avatar
18 votes
Accepted

Does converting image file formats affect quality?

Going from JPG (which is a lossy format) to any lossless one (like PNG) does not. Going from any format to a lossy one, yes, including JPG to JPG. It could be too little to notice, and using the same ...
Rafael's user avatar
  • 24.9k
15 votes

What makes RAW files difficult for manipulation?

Nothing makes raw files difficult to manipulate for someone with the right expertise and tools. It's just that there aren't many folks around who have those tools and expertise. The tools needed to ...
Michael C's user avatar
  • 175k
15 votes
Accepted

Why does the histogram of an image depends on the software that opened it?

It's all to do with the profile applied to the raw files and guesses other software makes as to what that profile ought to be... RAW is not an 'absolute' format in terms of the image displayed, it's ...
Tetsujin's user avatar
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15 votes
Accepted

Is it better to continue shooting in JPEGs instead of RAW if you are not planning to do post processing?

"Better job" is subjective. We certainly get lots of questions like Why does this camera generated JPEG look better than the software generated one? Why do RAW images look worse than JPEGs in editing ...
mattdm's user avatar
  • 143k
15 votes
Accepted

How sharp are RAW photos before processing?

Are RAW images by nature slightly blurry prior to processing? If I open them up in Lightroom and zoom into the photo, my photos are not tack sharp but a bit blurry. Once I process, it comes out ...
mattdm's user avatar
  • 143k
15 votes

Can you "open" RAW camera files?

It is all already said, I just want to make a meme and a philosophical exercise. Here is a JPG file opened... on a program that does not make a "preview" of the file. I prefer one that ...
Rafael's user avatar
  • 24.9k
14 votes

While shooting in RAW, do you have to post-process it to make the picture look good?

Raw data must always be converted in one way or another for it to be a viewable image at all. When you open a raw file using any image viewer application you are not viewing the raw image (because ...
Michael C's user avatar
  • 175k
13 votes
Accepted

Why don't cameras show an "accurate" histogram?

Why don't cameras show a histogram based on the RAW data rather than on the JPG preview? My notion is this: Because it would not be useful, because raw images don't yet have white balance in them, ...
WayneF's user avatar
  • 12.9k
13 votes

Why do we use RGB instead of wavelengths to represent colours?

The reason cameras and displays work in RGB is because our retinas work that way. Since our eyes encode colors with those components (RGB), it is a very convenient system (although certainly not the ...
heltonbiker's user avatar
13 votes

What does an unprocessed RAW file look like?

It's a really really big grid of numbers. Everything else is processing.
WolfgangGroiss's user avatar
12 votes

Why do we use RGB instead of wavelengths to represent colours?

An attempt to answer simply: We cannot practically capture enough information to store a complete breakdown, frequency by frequency, of all the different wavelengths of light present, even just ...
thomasrutter's user avatar
  • 13.6k
12 votes
Accepted

Why do we use RGB instead of wavelengths to represent colours?

I think there are some misconceptions in prior answers, so here's what I think is true. Reference: Noboru Ohta and Alan R. Robertson, Colorimetry: Fundamentals and Applications (2005). A light ...
Guest's user avatar
  • 136
12 votes
Accepted

How does one actually *use* a dark frame?

Straight away I should mention that lunar photography is different that astrophotography of deep-sky objects. The types of frames you are describing (calibration frames) are extremely helpful for ...
Tim Campbell's user avatar
  • 3,937
12 votes
Accepted

Can RAW image files deteriorate over time?

RAW files no more deteriorate over time than a DOC file would. As long as you store them correctly (with backups of course) the file will be fine. It's true that the software that you use to process ...
David Gibson's user avatar
11 votes
Accepted

What exactly does DRO do, and how does it work?

DRO stands for Dynamic Range Optimization. It is designed to fit more dynamic range into images. A single exposure is still taken so you are always limited to the sensor's latitude. However, from what ...
Itai's user avatar
  • 103k
11 votes
Accepted

Why can software correct white balance more accurately for RAW files than it can with JPEGs?

Why can software correct white balance more accurately for RAW files than it can with JPEGs? There's a fundamental difference between working with the actual raw data to produce a different ...
Michael C's user avatar
  • 175k
11 votes

Given an image how to identify whether it is RAW file or not

Trivial ways to recognize whether a file is a RAW or a JPEG: File ending: JPEGs end with .jpg or .jpeg, RAWs end with different ...
flolilo's user avatar
  • 6,468

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