canon Lee

First of all understand that a Raw file is data not pixels. It is information about the image, not a picture file. All camera's shoot in RAW and some of the smaller ones shoot in RAW+ JPEG. ( Only DSLR's can export Raw files, since the smaller ones convert the output to JPEG's). In RAW you can change the image as far as exposure, WB, etc. just by changing the data. Once converted to a JPEG, you now have an image made up of pixels. There is very little changes you can make. A TIFF file saves all of the info. Lets say you are in PS and you have lots of layers and changes you have made, saving a Tiff saves all of your layers and pixel manipulations. JPEG on the other hand compresses the image, throwing away your layers as well as repeated pixels adjacent to each other. You wind up with a smaller file. Printers on the other hand can only print JPEG or sJPEG. RAW files are for post editing and JPEG's are printable files.

Apaflo Loc: Anchorage, Alaska

Lets be pedantic though, and get it exactly correct. You don't process "with the RAW format", ever.

The RAW converter first demosaics the raw sensor data to produce an RGB image. That is what you edit while working in the RAW Converter. When it is saved you save RGB data (not raw sensor data). Whether it is saved in TIFF format, PPM format, JPEG format or some other RGB format is not significant. When that saved file is read by an image editor it decodes the file's format and produces the exact same RGB data that was saved. And editing can continue on the RGB data. (Except that it might not be the exact same data if lossy compression is used. JPEG always uses lossy compression. The other formats may or may not, but usually don't.)


JPEG always does at least some compression, and it is always lossy.

Take any 8-bit TIFF image and convert it to JPEG... the file size will be significantly reduced. That is compression.

As an example to show typical file sizes, I just used an 8-bit uncompressed image (a rather large one, produced by a D800) that has a 109MB file size to produce an 8-bit compressed (Adobe Deflate) TIFF file. That file is 43MB. I then used each of the TIFF files to generate a JPEG with maximum quality (minimum compression). Each came in at 29MB. But the really interesting part is using a binary compare program on the two JPEG files showed there were zero differences! (That is a great demonstration of lossless compression used by the TIFF format.)

And then the process was reversed, and from one of the JPEG image an uncompressed TIFF file was produced. When the binary compare was run on that file and the original uncompressed file there were 45 million bytes that were different. (That is a great demonstration of lossy compression used by the JPEG format.)



How interesting! People often look a bit down on "snapshots", but that is exactly the major purpose for most photographs taken! Memories! (I tease people that if they've heard of folks that will bore you to death with their vacation pictures... well I will bore you to death with your own vacation pictures! I sit there and carefully examine whole albums full of snapshots! It's wonderful stuff.)

redrocktom Loc: Sedona

Your DNG conversion files must also contain the NEF file, otherwise my experience is that the DNG will be slightly smaller than the original NEF.

Collie lover Loc: St. Louis, MO

I tried RAW and didn't like it. I shoot in jpeg and save in tif.

jcboy3

DNG is an open format developed by Adobe, and thus not proprietary.

On the other hand, JPG is a proprietary format, and so is TIFF (copyright for TIFF is currently held by Adobe).

romanticf16 Loc: Commerce Twp, MI

If you store the RAW files or convert to DNG you can always create a jpg; tiff; png orPDF as needed, and still retain the original sensor data as captured.

OonlyBonly

RAW then do your processing. Keep the RAW file because you might want to reprocess it later - years later even - and it'll still have all the original information.

Delderby Loc: Derby UK

Thanks for that - so "100%" is misleading - it simply represents the largest JPG that can be saved - which is only 40% of the original file?

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

correct!

jcboy3

Nothing here to "understand" other than you are wrong.

RAW files are camera dependent image file formats that contain minimally processed image sensor data, camera sensor metadata, image metadata, image thumbnail, an optional JPG preview, and the sensor image data (which for the common Bayer sensor is a pattern of two green, one blue, and one red pixels).

Unless the camera can produce a RAW file output, it cannot "shoot in RAW". Smaller cameras usually do not produce a RAW file output, but some do. Many non-DSLR cameras can output RAW files (mirrorless, bridge, and some compact cameras).

Every camera I have seen that can produce a RAW file output can produce a combined RAW+JPG output.

A key advantage of RAW files is that white balance can be changed without degrading image quality (because the color channel data is preserved in the RAW file). Exposure can be changed in RAW or JPG without issue (other than the IQ degradation due to saving JPG files multiple times).

JPG format is NOT a pixel format, it is a compressed format.

Printers can print from a number of image formats; depends upon the printer. But if you are printing from your computer, the printer interface is not based upon JPG. The application you use and the printer driver will convert JPG to whatever format is used by the printer, usually a raster image format.

Dngallagher Loc: Wilmington De.

Agreed - I reread my comment and it sounded like I was saying dng was proprietary, not what I mean to convey.

canon Lee

Thank you for you reply. You are technically correct. I was trying to assist a new bee by answering his question as simply as possible in order to avoid a long in depth reply. Some times it is easier to understand if things are not so technical. Thank you for your reply.

marcomarks Loc: Ft. Myers, FL

I have to disagree unless you're using the special layered-TIFF. A typical everyday TIFF is not reversible or tweakable because there are no layers.

I think this lack of distinction is muddying the waters of understanding and it's why you've been asked if you are confusing TIFF and RAW.

Once a file is saved as a common non-layered TIFF it is permanently that way just like a JPG. The main difference is that the non-layered TIFF is not compressed and is lossless versus the JPG which is compressed.

Photoshop .PSD files are the Photoshop native format that retains everything in a reversible layered format. I assume, but have never seen it in print, that .PSD files are a proprietary file similar to the layered-TIFF you are using.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Marco, the layered tiff is not a special or uncommon anymore than an unlayered tiff is commonplace. Compression is an option that is available when you save - and can be applied to either a layered tiff or an unlayered tiff. If you are in Photoshop and you have a file with layers, the save dialog will have the Layers box checked by default, and you can choose to save it uncompressed or lwz compressed with a couple of options for size/quality.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Sorry, but there is still material to understand here. You have, despite your best intentions, managed to muddy the waters a bit.

Raw files are proprietary files but they are not image files. You cannot see/print/edit a raw file, but you can view the interpretation of a raw file in the jpg preview, and you use that preview to edit. But in addition to the list of contents you provide, you left out the most important one - it contains the proprietary picture control settings specific to the camera and manufacturer. These are not read by generic raw converters like Lightroom, Capture One, etc, but can be read by the mfgr's raw software.

Bayer is not a sensor, it is a filter that separates light into the three different colors so that it can be interpreted as color when recombined in software and processed into an image file.

White balance is not "saved" in a raw file - you assign the white balance when you process it. The raw file contains only the white balance setting, and will display it when you view the jpg preview, but assigning the white balance in a raw converter is absolute, and not an adjustment to an existing value, hence you change nothing. You assign it, or you can select to keep the value that the camera was set to.

All cameras shoot raw. Nearly all cameras have built in raw conversion to jpg, which they do according to the camera settings at time of capture.

The key and most important feature of raw files is that all image parameters are nondestructively adjustable, with greater range, than anything possible in the camera, and you can do this with no data loss, at a higher bit depth (more accurate colors and smoother tonal and color transitions), with finer detail capture, a much larger color palette, (billions of colors and tones vs 16.7M) and greater dynamic range than is possible with an 8 bit compressed jpeg image.

Technically, jpeg is not an image or a format, but a compression algorithm. You can make exposure adjustments in a raw file before you commit to an image format with far less negative impact than you can to a jpg file, which is hugely destructive. Tiff files are preferable, as they can be 16 bit, large color space (ProPhoto), and far less destructive, primarily because of the greater bit depth and absence of compression. You simply cannot adjust a jpeg to the same degree you can a raw file or even a tiff file and still maintain the same image integrity.

So I will compliment you on attempting to clarify things, but if you are going to do that, please make sure you "own" the material you present. CanonLee was absolutely on target with his commentary, you just wandered off into the forest without your map and compass (or GPS these days). Nothing personal, but it is important to make sure that information presented as fact is in fact accurate.