Raw file Formats in Cameras

Most cameras will produce JPEG files, a processed camera file that can be quickly uploaded and shared across all online social media. This day almost all cameras and iPhones can be set to record in raw format. A raw format is an unprocessed image that contains all the information the camera records, which is not the case with a JPG file. Each camera manufacture uses a different raw format. However, a few use a DNG raw format, developed by Adobe, designed to be a universal format and used with all Adobe products. Leica, Hasselblad and Pentax have adopted it.

Table of Raw Camera File Formats

.3fr (Hasselblad) .ari (Arri Alexa) .arw .srf .sr2 (Sony) .bay (Casio) .braw (Blackmagic Design) .cri (Cintel) .crw .cr2 .cr3 (Canon) .cap .iiq .eip (Phase_One) .dcs .dcr .drf .k25 .kdc (Kodak) .dng (Adobe) .erf (Epson) .fff (Imacon/Hasselblad raw) .gpr (GoPro) .mef (Mamiya)

.mdc (Minolta, Agfa) .mos (Leaf) .mrw (Minolta, Konica Minolta) .nef .nrw (Nikon) .orf (Olympus) .pef .ptx (Pentax) .pxn (Logitech) .R3D (RED Digital Cinema) .raf (Fuji) .raw .rw2 (Panasonic) .raw .rwl .dng (Leica) .rwz (Rawzor) .srw (Samsung) .x3f (Sigma)

Benefits of Raw Formats

• Areas of the image that are under or overexposed areas reveal fewer artifacts when rendered in raw format.
• Larger colour gamut, therefore more shades of colours
• More accurate image quality.
• More dynamic range information is available for adjustment.
• Avoids JPG engines the produce undesirable results
• The format is non-destructive only the metadata that adjusts the rendering is changes.
• Unlike JPGs raw files dont slowly degrade each time you save the file.
• You have finer control over white balance, hue, saturation, colour channels, etc.
• You can change the colour space if you need too.
• You can choose a different demosaicing algorithm process from the one the camera uses.

JPG Versus HEIF/HEIC/HEVC

JPG and HEIC file formats are two raster files that compress to a smaller size, making them easier to send via emails or post to social media. JPGs use a “lossy” compression process, whereas HEIC uses a “lossless compression” process. The problem with “lossy compression” is that each time you save the file, it rewrites the compression, and over time, the image degrades. HEIC, on the other hand, uses a “lossless compression” process and does not degrade. The second advantage of HEIC is that it has smaller files, sometimes half the size of a JPG. A third advantage of HEIC is that it improves the image’s transparency and has a broader dynamic range capacity.

The potential disadvantage of a HEIC file is that it is relatively new; JPGs created by the Joint Photographic Experts Group came into use in 1992, and have been incorporated into almost every program or application, whereas HEIC was created in 2015 and only adopted as a standard by Apple in 2017 Android systems receiving support for this format in 2019. Most modern cameras are now adding the ability to save files in HEIC format, allowing camera users to save each photograph in HEIC plus RAW simultaneously. So it is rapidly being adopted as the new standard for compressing files.

In my opinion, if one is going to compress a file, one should always do so in HEIC format to prevent loss of quality over time. If an older application or program has not yet upgraded its software to take HEIC files, you can export a JPG. I imagine HEIC will become the new standard for all devices over the next few years, so one may as well.

What is the difference between HEIF and HEIC? HEIF is the file format used to compress the file. HEIC holds HEIF image files but uses the HEVC format to include file image sequences and metadata illustrating each image. Apple uses HEIC to allow one to create short forms of animation using the live view feature for the content of the file. I suspect this also allows you to look at various moments of an image, find the frame where your subject’s eyes are open or smiling, and reset the image to that moment.

Digital Image File Storage Formats

Cameras all use different proprietary camera storage formats for their RAW files, although some do use DNG, in addition to being able to produce JPG files. RAW files contain all the information the camera records, whereas JPG files delete a lot of this information when it processes the image in the camera. In editing software like Lightroom, Capture One and other post-processing software, RAW files are designed to be processed outside the camera. Camera formats are raster formats, which means they are fixed size instead of vector files used in graphic programs, which can be expanded and contracted. Below are several formats that you may encounter regularly.

• .HEIF (High-Efficiency Image Format, sometimes referred to as HEIC) is a smaller photo storage format than JPEG. It is now the format used by Apple and Google Android phones. When exported to a computer, it usually automatically converts to a .JPEG or a .JPG. The video equivalent is HEVC (High-Efficiency Video Compression).
• .JPEG or .JPG is a lossy compression software for storing images, where one can control the degree of compression. However, increased compression results in decreased image quality. Also, every time it is recompressed, image quality degrades, hence the term lossy compression. It is an ancient standard established in 1992 and replaced with far better formats such as PNG and HEIF, but the format is still ubiquitous.
• .JPEG 2000 This format allows for both lossless and lossy storage. It is not accepted widely for photographs but is used in professional video editing and distribution.
• .PNG (Portable Network Graphics) is a lossless data compression format for storing images, so image quality stays the same (so not lossy compression). This is one of the better, more modern image formats and can be used in place of GIFs and JPEGs. It also has a smaller file size.
• .TIFF (Tag Image File Format) is an image storage lossless format, so it may be edited and saved without losing image quality. It can contain the image information and other data, and even JPGs, within the format. The file format does become rather large the more you edit. A 56mp image can grow to 150mp in just a few edits.
• PSD (Photoshop Document) It is primarily used in photoshop, but many other programs use this format for editing and storing images. Although it is a more compact file than a TIFF, it too is fairly large as it contains all the editing decisions that have been made to the image.
• .Exif (Exchange Image File Format) This file format is embedded in .JPEG, DNG and other camera image formats contain the camera’s metadata. It is embedded in other file formats such as the camera’s shutter speed, aperture setting, time, date, speed, name of the camera, and other information.
• .GIF (Graphics Interchange Format) This format is used to store graphics and allows for short animations of graphics and images. It is universal and uses lossless compression.
• .BMP (Windows Bitmap) This format is usually uncompressed larger and lossless. The format is widely accepted in Windows programs.

Digital Image File Storage Formats Used in Graphics

Graphic programs use vector storage formats which allow files to be expanded and contracted without losing resolution. When looking at a vector file on a computer, you are looking at a temporary rasterized version of the image; if the image size alters, the program then recreates a new rasterized version of the image. There are many of these formats, but SVG is the dominant format.

.SVG (Scalable Vector Graphics) This format is the open standard for most vector programs

RAW Processor Variance

RAW processing programs initially interpret RAW files differently, and this can have an impact on how one sets about adjusting an image. Although it is possible to achieve similar results from most processing programs, there is a difference in how each program interprets tone and colour. In addition, each program has, for example, different ways of manipulating clarity, colour, edge sharpening, contrast, and dynamic range, as well has how they structure masks and use AI tools.

The following is an example of the initial difference between opening a RAW file in Capture One and Adobe Lightroom.

In the case of these two programs, both have an auto-adjust tool designed to speed up the processing of images. The following two examples illustrate the difference between these two automatic adjustment tools.

In my opinion, even though I could use either of these two pieces of software to create very similar images, it is quickly likely that different starting points will likely create different outcomes. The difference may be slight or significantly different.

Smart Phone Files, the Frontier of Innovation

Smartphones have integrated much more advanced sensors into their cameras; these newer sensors eventually migrate into larger cameras. In addition to this, because of the small size of the sensors, they have been using artificial intelligence (AI) to keep improving image quality. For example, Apple ProRAW format in the iPhone 12 uses smart HDR, Deep Fusion, Night Mode and Semantic Segmentation Masks to improve image quality. Once again, I suspect all these innovations will eventually migrate to larger cameras.

References:

• What is Apple ProRAW and how does it change the game for smartphone photography?
• Computational Versus Traditional Photography Complementary, Not Contradiction
• About JPEG Images and Their Quality Degradation, Fstoppers