Spring 2012

Spring 2012
by ani

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253

The Value of RAW: I think you may be misunderstanding the value of RAW. In the grand scheme of things, from seeing a scene with your eye to printing it, the best you get is what the printer you printed with is capable of, and that tends to be considerably less than what you see, or your camera or your computer is capable of representing. The value of RAW ...


91

Here's a concrete example of the advantages of shooting raw from a recent wedding. I always shoot raw+jpeg and use the jpegs to quickly sort through the photos afterwards. Here's a jpeg of the first dance that would have gone straight in the bin, except for the fact that I had very few shots of the first dance due to some very difficult conditions: I ...


56

The JPEG format has the advantage of giving small files. The RAW formats have the advantage of preserving all the data collected at the shot. The PNG format gives neither of these advantages, so you don't even get a compromise between the other formats, you get almost only the drawbacks from both formats.


51

This is based on a misunderstanding. Loss of quality happens only during the compression that is done when an image is saved as JPEG. But it doesn't matter whether it was edited or not. So: you will (with some very specific exceptions, see comments) lose quality if you open an image in an image editor and re-save it, even if you didn't make any edits. But ...


50

If the dimensions of the image are multiples of 8 (or 16 if chroma subsampling is used) then the rotations are lossless. Otherwise it is not possible to rotate the image without recomputing the blocks i.e. recompressing the image, which is lossy. The reason for this is that jpeg images are broken up into a series of 8x8 or 16x16 blocks which are compressed ...


40

Image size notes aside, a big reason is that PNG does not have a standardized means of EXIF embedding and that will immediately shy the camera makers away from it. There would be a lot of information lost by doing image conversion to PNG in camera as a result and, for the most part, would probably been seen as a negative by most photographers.


37

I expect pro-RAW answers will dominate here, so I'll offer a pro-JPEG view. I was shooting RAW from the start when I started using digital cameras. However, after a few years, when looking into my workflow, I realize that I very rarely use what RAW offers (post exposure white balance changes, exposure corrections and so on). My typical adjustments to the ...


36

RAW: Pros: Great color More post-processing options Cons: Large File size More storage needed Slower capture time More complicated workflow for processing JPEG: Pros: Fast capture (so higher burst speed) Simplified viewing/sharing Cons: Finalized (editing degrades the image more) Smaller range of color/contrast options.


36

I was a beginner at the time, took this picture of a very nice sunset. I was pretty disapointed by the picture... Once I learned how to properly use Lightroom, I was able to get most of the details back from the original RAW file to get it to what I was really seeing in real life.


35

Although Philip's answer is the best way to go, it is possible to do what you want entirely within the sphere of JPEG. JPEG works by breaking your image up into blocks called Minimum Coding Units (MCUs), typically 16×16 each, and compressing them separately. You can see this in images when you crank the compression level up very high. At more ...


33

I will add my own input. Doing this specifically isn't the reason to shoot RAW, it's just the primary reason why shooting RAW gives you fundamentally more headroom to work with when pushing pixels around. I took this shot at a show a mate of mine was playing at (in this actual band). 1/60th ISO 1600 f/2.8 on a Canon 50D with EF-S 17-55mm F2.8 lens. Here is ...


33

Try JPEGSnoop: JPEGsnoop is a detailed JPEG image decoder and analysis tool. It reports all image metadata and can even help identify if an image has been edited. As explained on the JPEGSnoop webpage: One of the latest features in JPEGsnoop is an internal database that compares an image against a large number of compression signatures. JPEGsnoop reports ...


28

I am an amateur photographer going semi-pro and even though I still only use RAW I have come across a few occasions where RAW+JPEG was needed (or at least would be a great convenience): ready to email files (like @rowland-shaw wrote) - some times you need to get your photos out there as fast as possible lite photo files to browse through - given that your ...


28

Beyond the very obvious memory card requirement differences between RAW and JPEG images as noted in the question: JPEGs are compressed and typically have much smaller file sizes. For example a RAW file from a Nikon D800 can be 50MB and the JPEG may be a fraction at 10MB. This benefits not only memory card capacity but also editing workflow speed, archival ...


28

In addition to the points Alex S made, you need to consider why they want RAW. There are several possible reasons: Bit depth as Alex S said. JPG suffers from compression artefacts which RAW doesn't. Blown up to exhibtion size these can jump out and ruin a print. Having the RAW file is often used as a proxy for having taken the photo, as RAWs aren't ...


27

RAW is not (or minimally) processed image data from camera sensor. JPEG is processed image data. Typically, raw-files from modern cameras have 12-14-bit per pixel which means up to 16384 values (for more details see Michael Clark's comment). JPEG can have only 256 luminance values per RGB channel. This means that jpeg contains much less data than a ...


25

PNG may use a lossless compression algorithm, but it is lossy in comparison to the raw data. You lose bit depth, the camera may introduce demosaicing artifacts, you may bake in a bad color balance, the camera may apply inappropriate sharpening, the in-camera noise reduction may wash out detail, etc. I don't think there's a big demand for a format that's as ...


22

jrista pretty much summed up the whole difference, but just to clarify on the point of RAW headroom: JPEG is 8 bits, meaning 256 discrete levels per channel (RGB) which creates quite a wide range of color (16,777,216 discrete colors to be exact), but that pales in comparison to what RAW can potentially offer. The actual number of bits that a dSLR sensor ...


22

In your command prompt, go to the folder and run this: for /f "delims==" %r in ('dir /b *.nef') do del "%~dpr%~nr.jpg" 2> nul Basically, it goes through the current folder, runs through the .NEF files, and deletes the JPG if present. It ignores any errors if the JPG is not there. If you want subfolders, include "/s" (without quotes) in the dir ...


21

Absolutely not. You need to edit the file and re-save it as a JPEG in order to compound the effects of image compression. Just viewing it has no effect at all — if it did, all of the JPEGs on the web would "wear out" completely in a day or two at most.


20

I capture everything both raw and jpeg, it gives you the best of both worlds. Take this original jpeg: Normally you would probably junk this shot, its totally overexposed. Correcting it in photoshop is not going to give you more detail: Contrast this with the RAW shot, which was underexposed 1 and a half stops during post: You get significantly ...


20

Let's consider the image captured by the sensor (RAW) as calibrated and neutral. The equation is the following to generate a color balanced JPEG is: JPEG = RAW * T where T is the color balance transformation Normally to apply a different color balance to a JPEG, you would need to apply the inverse of as-shot transformation to the JPEG (to restore the ...


20

A JPEG may start out with 8 bits per R, G and B channel, but when stored in the JPEG it is stored very differently, where there is no real "bit depth" but instead values are stored as frequency coefficients of a given precision. In JPEG what's more relevant is the quantization rate, which affects how much information is thrown away during the quantization ...


19

In the RAW+JPEG workflow, JPEG is what you shoot for. RAW is the safety net. The primary benefit or JPEG is not smaller files (that's the second), it is that JPEGs are actually images. Images have advantages over RAW files, already mentioned by others: quick preview, ready to email, no processing required, etc. Once the shot is taken you are done if you did ...


19

These two formats are different: JPEG general info JPEG is used to store images on smaller disk space JPEG compression algorithm changes image data while converting it. Amount of change can be controlled but not its location which is always around sharp colour changes JPEG is primarily an RGB format If you saved and opened the same image several times, ...


19

JPEG 2000 has not garnered wide acceptance due to a few factors. Lacking backwards compatibility to JPEG Lack of wide browser support Questionable legal status (Only) 20% higher performance, while considering how inexpensive storage is Additional processing power/time needed to create JPEG already considered quite good Amount of rework to the code in ...


19

"To ensure that my photos display in the highest possible quality for display on Facebook, re-size your photo before you uploading" The supported sizes are: Regular photos 720 px, 960 px, 2048 px High Resolution Cover photos 851 px by 315 px (keep cover photos under 100K to avoid Facebook compression) (JPEG with an sRGB colour profile) Any other ...


19

The point to remember here is that you lose quality when saving the photo into a lossy compression format. So long as you save the photo in a lossless format (PSD, TIFF, etc) after adding the border, you won't lose any more data than you've already lost by saving the photo as a JPEG in the first place.


18

The reason you got confused is that it's not the file size that is displayed in Photoshop. Photoshop's status bar shows uncompressed size of image. With three 8-bit color channels, that's 3 bytes per pixel, resulting 34.9 MB for a 4288 x 2848 image from your camera. JPEG is a compressed format, so the actual file is smaller. Showing compressed size would ...


17

Not really. Weirdly, "jpeg" is really the name of the compression and not the standard for the file format that bears the .jpg name. There's various different container formats that can hold jpeg-compressed streams. The official one is JFIF, although by strict reading files containing EXIF data don't properly correspond to that spec. (Aren't standards ...



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