will i lose data/quality converting my raw files to jpeg on my pc? [duplicate]

Question

will converting raw files to jpeg be the same as taking a jpeg photo to begin with? or will I keep my raw quality converting it to jpeg post shoot?

Answer 1

JPEGs have a narrower range of features than RAW files, so you can expect that your generated JPEGs will be no better than your original RAW files. Depending on what features and format were used to record your original RAW data, you may notice significantly reduced quality.

Three major areas where you can be assured a JPEG cannot equal are a RAW file are Color Depth (Sampling), Color Space (Gamut), and Image Data Compression. Here's a quick enumeration of what's different:

Color Depth
RAW: Any sample bit depth is available, 16bit is typical nowadays.
JPEG: 8bit only (16bit is possible in the updated JPEG2000 spec).

Color depth is the one key area where JPEGs cannot match RAWs, especially any RAW file with 16bit samples. This manifests itself in the form of reduced tonality, and in the most severe case, block-like artifacts in JPEGs when the output quality level is reduced. Some images benefit from dithering to improve their relative fidelity to their original image, which can visually make a JPEG look as good as the original to an untrained eye.

Color Space
RAW: Any color space is available, and usually this is some form of expanded gamut specific to the manufacturer and class of capture device. You can expect to see gamuts that can meet or exceed sRGB, Adobe RGB, etc.
JPEG: Only sRGB, Adobe RGB, or Unspecified (often interpreted to be some form of RGB) are widely used.

In theory any ICC profile could be embedded in a JPEG, but the most common display mediums often have undefined behavior with any color space that isn't sRGB.

You may not see much degradation here, as most current display devices are sRGB based, and not many people have displays with an expanded gamut. Printing is where you will likely see an issue, as the sRGB space has significant areas subject to interpolation when rendered with ink; and in high-end printing, both sRGB and Print CMYK-based spaces have large areas of exclusion to each other where colors from one space can never be reproduced exactly by the other.

Image Data Compression
RAW: No compresssion or Lossless compression are the norm.
JPEG: Lossless compression is available only under very specific circumstances.

Most RAWs from cameras contain some form of sensor data or directly converted samples based on sensor data. These are lossless and can be converted with high fidelity to another compatible or similarly capable format (TIFF, DNG, etc.).

With JPEGs, many editing tools have their own interpretation of what is lossy and what isn't, leading to significant degradation on round trip open/edit/save operations on the same JPEG file, and some non-professional editing tools aren't truthful about saving JPEGs in a lossless mode at 100% quality. Because one of the design goals of JPEGs was to trade size for quality, you can expect JPEGs to almost always win on size due to use of lossy compression, but rarely keep up on quality.

It's a little bit trickier to enumerate what looks visually worse about a JPEG due to compression levels, as the high end of the range looks pretty good, and many images have compositions that don't look that much worse to untrained eyes until the compression level gets really high. Some attributes that eventually manifest as the compression ratio increases are muddiness/weak contrast, false colors, and block-like image details.

Subjectively, you have to decide whether you want to record images or samples in RAW or as JPEG. Here are some of the trade-offs when making this choice for cameras:

Negatives
RAW: Slow writes to media (SD/CF cards, etc.) and may exhaust camera shooting buffers quickly when shooting long bursts. Slower workflow after-capture, as your tools may require image conversion to TIFF or JPEG or other formats.
JPEG: Greater chance of missing and irrecoverable image details if your shot was exposed badly. Weak color and detail in many types of scenes where color, micro-contrast, and image details matter, such as landscape and portrait photography.

Positives
RAW: Best possible image quality from your device. The capabilities of many high end cameras may only discovered by starting your workflow from RAWs.
JPEG: Often the fastest possible shot acquisition for many devices; and simplest workflow after-capture, which is ideal for scenarios such as social media, surveillance, and photojournalism where time-to-distribution often counts the most.

Whatever you choose for your needs, you would be best served by keeping a copy of whatever original you obtained from your device. This way, if you find that your workflow have lost a lot by working with JPEGs, you can start over from the original image data, which is the best representation you can retain.

Answer 2

RAW files are data that really cannot be displayed on your computer screen; for example RAW often has a color depth of 12 or 14 bits per channel, screens can only show 8 bit (except those very new hdr displays..). Jpeg is also an 8bit format.

So every time the raw sensor data is converted to jpeg (in camera or on your pc) or software tries to display it on screen, a decision has to be made how to reduce these 12 or 14 bits to 8.

In-Camera jpeg creation and also any software displaying raw files do this automatically, which is the easy way. Doing the "reduction" (developement of the picture) manually allows you to decide for yourself about how to use the information overhead, which is a bit more time consuming but lets you choose how the image should look.

So: image quality is not really different, necessarily, but developing a jpeg from raw gives you more control over the image, which might just decide whether the resulting picture is a good one or just any shot.

Answer 3

It depends.

Some of the factors involved:

• The results of the camera's jpeg engine versus the jpeg engine of whatever raw processing application you choose. Different applications will handle the same raw data differently to one degree or another.
• Your skill in using the camera's controls and settings to affect the outcome of the in-camera jpeg versus your skill in using the raw processing application's much more sophisticated and flexible settings and tools. There are some things you can only do with a raw file on a computer that you can't do in-camera. But like many advanced tools, it takes knowledge and experience to use them properly. Without the needed skill, the automatic solution in camera will likely result in a more pleasing image.

Answer 4

The short answer is: it depends.

You can make from your raw file a full jpg, which will keep full quality. It will also be huge.

When converting from raw to jpg you lose options for further image manipulation. This is not quite the same as image quality. You can make a black & white jpg from a raw file, it will have full resolution but there is no way to make the jpg color again. You could however, reprocess the original raw file to make a different color interpretation.

It is often practical to make a limited resolution jpg of acceptable quality for distribution. And the limiting of further editing is not necessarily a bad thing - export to jpeg is a way of declaring the image "final".