What are RAW images and how do they differ from normal images?

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I’ve listened to many tech reviewers and photo editors saying that RAW images are better and have been intrigued by it. Also what are it’s merits and demerits?

In: Technology

11 Answers

Anonymous 0 Comments

raw images are uncompressed.
Compression removes a lot of detail, and some steps of that are lossy ( detail can not be recovered ) an example is chrominance downsampling, as chrominance is not perceived by the human eye, the detail is considered unnecessary and is removed so to reduce the size of the image. If a movie shot in RAW wasn’t compressed, it would be 100s of gb and would take 10s of DVD’s to watch.

Anonymous 0 Comments

Raw format is the unprocessed data captured from the image sensor. Many DSLRs and similar cameras can capture 10–14 bits of data per color channel, more than the 8 bits commonly seen. This allows more detail to be captured, more subtle edits can be made, and smoother changes in color. There is actually more data than can be shown on a standard monitor, and thus a lot of leeway when it comes to fine adjustments.

Raw format files have much larger filesize than JPEGs processed from them. They are often unique to a specific model of camera, and cannot be viewed on other devices without first installing the codec, or converting to a more common format (such as Adobe DNG).

JPEG format is widely available (the codec is already present on all devices), and can maintain perhaps 90% of the apparent image quality for around 10% of the filesize. However, it does this through a lot of approximation, sacrifices in color fidelity, and elimination of all excess data (8-bit color channels). Edits made to JPEGs easily reveal all of the shortcuts and shortcomings.

Professionals primarily shoot in raw format, and save the JPEG conversion step for last, since the quality loss is otherwise unacceptable.

Anonymous 0 Comments

Your camera has a sensor made up of thousands of little light detectors. A raw image stores the reading off of all of them.

Any other format takes the raw image and removes information considered redundant. For instance, if you want to display an image on a 1024 X 768 display, there is not much point in having 4096×1920 individual points – so the format averages them.

Raw – advantage is no lost data. Disadvantage, needlessly huge file.

Jpg – advantage, no discernable difference in image, but much smaller file size. Disadvantage = you lost some data. Maybe you need it for some post processing purpose – printing in a larger format, for example, or applying a complex filter to alter the image.

Anonymous 0 Comments

RAW is just that, raw data, it’s all of the data that the camera captures – it’s a lot so the files are huge. So the cameras will convert them into JPGs using some serious compression and it does this by throwing away 70-90% of that data.

For point and shoots it’s not too much of an issue, but when you process photos digitally you want all of the data to play with.

For example, a photo of the night sky in RAW might have 100,000 tones of black, but in JPG it might be 20,000.
The JPG will show a black sky, but using software like Adobe Lightroom, you can make adjustments to show all of the stars and galaxy in the RAW version

When you’re editing you can tweak the levels to bring out all of the extra detail in the shadows, highlights and colours. With JPG you can’t do that because the data simply isn’t there

RAW is always better to shoot if you can and you want to process your photos to the best of their ability

Anonymous 0 Comments

As others have said, RAW files are a full record of what the sensor detected. The RAW files themselves are hardly ever edited, but images to be displayed or printed will be generated from the data in the RAW files and saved in some other format (such as JPEG). The process of generating the display image from the RAW data will include various manipulations (such as sharpening, noise reduction, contrast enhancement, colour balance and additional compression).

If you shoot RAW only, you’ll have to use special software to open the RAW file, apply the required enhancements and save the image to JPEG (or some other format) afterwards. If you shoot JPEG only, the process is basically the same, except it all happens in the camera using the camera settings you’ve selected; the RAW image file is not saved. This means that the settings that were applied to the RAW data are cooked into the JPEG and can’t be undone or changed later (at least not perfectly).

The vast majority of people who express an opinion online about this stuff will say you should shoot RAW. I’ll offer a contrary view: I think for many purposes the advantages are theoretical rather than practical. I used to shoot exclusively RAW on Nikon cameras, but when I switched to Fuji (and now also Ricoh) cameras, I struggled to produce images from the RAW files that looked as good as the out-of-camera JPEGs. I now hardly ever shoot RAW.

It’s perfectly possible to follow a workflow using an out-of-camera JPEG as the master image, where this master JPEG is kept safe and is never edited; all working edits are based on that master JPEG. It doesn’t matter how many further edits are made; the edits are always generated from the master, so there’s no additional degradation with further edits. (I follow such a “non-destructive” workflow in Adobe Lightroom using the out-of-camera JPEGs instead of the RAW files.)

For some images, such as charts and logos, even a modest amount of (lossy) compression can lead to visible compression artifacts, so JPEG is not a suitable format for this sort of image. But for photographs of normal subjects, modest levels of compression in the final JPEG will generate artifacts that are simply not detectable by eye. There are other theoretical advantages of RAW images, such as increased bit-depth leading to greater latitude in editing areas of similar tone before banding occurs. But in practice, I’ve rarely found any of these potential advantages to provide any real-world benefit and I have no plans to go back to shooting RAW. (As I mentioned, this is not a view you’ll see expressed online very often.)

Anonymous 0 Comments

If you give a raw file to 10 different people you will get back 10 different looking JPG (or whatever file format) images. The camera is doing the same thing when you take a picture. If you don’t have raw enabled then it’s just throwing away the raw data and giving you its idea of the best image.

When you manipulate the raw itself you can tune the image to your personal tastes and get exactly the look you want. Maybe you want a standard looking vacation photo. Or maybe you want a high contrast film noir look for your new portrait photography hobby. Or maybe you want a soft Instagram filter looking image. All up to you in raw.

Yes you can do similar adjustments with the JPG image but it’s way better to start with the base raw. JPG is like trying to remodel an existing house. You can do a lot more with a house- and do it more efficiently – by starting from the ground up before the foundation is poured. Same way with raw files.

Anonymous 0 Comments

Raw Image is every bit of data the camera sensor captured. Huge files, but the maximum amount of information to play around with when editing.

Normal Images (typically this means JPGs) are compressed, so they are much smaller and easier to share, but a lot of data has been lost so they can’t be edited as much.

Anonymous 0 Comments

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Anonymous 0 Comments

RAW images = what your camera sensor sees, normal images = what your screen shows.

There are a few differences: A sensor doesn’t really record colored pixels. Color is achieved by placing a filter in front of it – so some pixels will record only red light, some only green and some only blue. While your monitor does works in a similar way, generally there those “subpixels” are grouped together to full-color pixel units. This translation has to be done before an image can be shown.

And there are other things that have to be done in between the sensor recoding an image and a monitor displaying it. A camera would typically remove image noise, correct white balance (basically, remove any tinting that the lighting of your scene might have), and a lot of other different things. RAW images don’t include all of that and are taken directly from the sensor data, including more details about some over- or underexposed areas, that would just appear “completely black” or “completely white” in a processed image.

That means that RAW images aren’t really “better”, in fact they themselves are much worse pictures than a processed JPEG. They just allow you the freedom of doing those processing steps yourself (and adjusting the parameters to your liking) to get an even better end result – assuming you and your software are more capable than your camera (which might make some wrong guesses about how you want your photo to look).

Anonymous 0 Comments

The RAW images basically have no compression or image processing. Straight up raw byte values for each of the colours of each pixel direct from the sensor. Along with metadata and if your camera has a built in screen usually a thumbnail for that.

The downside is they are massive. If you have a 30 Megapixel DSLR, each picture is going to be some multiple of that depending on how many bytes per pixel it stores and how the sensor encodes its data. But at the most basic, you’d have 3 bytes per pixel so 30 Megapixel ~ 90 MBytes per image. And once you get to massive image size, not only is storage space an issue (less so now that 100+ GB flash storage is a thing), the storage _speed_ becomes an issue. Unless you have lots of onboard RAM that can store dozens of sequential exposures, how fast you can write the data to it becomes an issue. This is what separates a consumer from a pro DSLR camera that is capable of doing 15 frames per second in a multi-exposure like for sports photography, its memory cache and data handling speeds that can keep up with such a ludicrous data rate.

Upside is it has absolutely no processing, smoothing, image correction or anything. Its straight from the sensor, so it really is a true representation of what you viewed through the viewfinder.