Nikon has introduced a new type of RAW file – called RAW S – with the launch of their D4s professional DSLR earlier in 2014, as Nikon users were waiting for a Canon sRAW format equivalent. The rumor mill is claiming that the D800s (presumed to replace the Nikon D800/D800E soon) will also offer this so-called RAW S option. There is still some confusion regarding this new file type, so we are taking a closer look at it in order to understand what it is and what it actually does.
Most digital cameras are capable of shooting photos in multiple file formats. The most popular formats are JPEG and RAW. The former is already processed in the camera and compressed with a lossy algorithm, while the latter stores unprocessed data straight from the image sensor in an uncompressed or compressed form.
In general, regular photographers are using JPEG files, while some enthusiasts and professionals shoot in RAW because it allows them to edit and process the files using third-party software on their computers. Still, why would you want to take RAW photos?
What is RAW?
A RAW image file is considered a “digital negative”. Negatives are strips of sheet that contain all the data required to create a photo in film photography. Now that we have made the switch to digital photography, RAW files have replaced the negatives of film photography.
The data captured in RAW by a camera’s image sensor is not processed and it requires editing before being posted on the internet or printed on paper. Such files provide a wider dynamic range and contain much more information than your regular JPEG file.
Additionally, they allow photographers to correct and fine-tune any potential optical and color flaws caused by imperfections of the image sensor and lens.
On the other hand, a JPEG file is processed internally and it is ready to be printed. JPEG is the more convenient file format for pictures. However, a lot of data is lost and the editing headroom for a .jpg file is fairly limited.
In simple terms, a RAW file, be it 12-bit or 14-bit, contains all the information needed in order to create a potentially better photo, while a huge amount of post-processing can be applied to the file, such as correcting white balance. As a result, professional or enthusiast photographers can choose to shoot in RAW because the resulting images could look a lot better after editing when compared to a straight-from-the-camera JPEG image.
That’s not to say JPEG isn’t used by pros! If you are experienced enough to set the correct white balance, the correct exposure, the desired color space, and the needed picture settings (color, sharpness, noise reduction etc.) before you take the shot, JPEG could be just enough for you. Don’t forget one of the primary advantages of JPEG: it’s ready to be printed, used or shared online.
sRAW and mRAW formats are already offered by Canon
Digital cameras are now offering roughly 10 times the amount of megapixels found in the earliest digital cameras. Photographers capture a lot of photos, but the more megapixels a camera has to offer, the larger the RAW files will be.
Photographers will have to buy more cards to swap during a photo shoot as well as bigger and more expensive hard drives to store and back-up the files, so manufacturers have been forced to come up with a solution. Canon’s response consists of sRAW (small-RAW) and mRAW (medium-RAW) file formats.
According to Canon, mRAW offers all the benefits of a RAW file, however the file size will be smaller. The resulted mRAW files have 55-60% of the the camera’s native resolution, but two thirds of the file size of a full RAW. Still, users can edit the files and create quality photos, but prints should not be bigger than A3 size due to the decrease in resolution.
This method allows wedding and action photographers to capture more photos in burst shooting mode. However, it is also useful for users who do not need to shoot high-resolution photos because they will never print the photos at huge sizes.
The mRAW file size has been introduced in late 2009 courtesy of the Canon 7D and 1D Mark IV DSLR cameras.
sRAW is similar to mRAW, but the file is even smaller and has even fewer megapixels than mRAW. It has been available for the first time in the Canon 1D Mark III, a DSLR released back in 2007.
mRAW and sRAW also record fewer data than the full-sized RAW, but a fair amount of post-processing can still be applied by the users who do not need the entire resolution of a photo.
Although not all photographers are shooting sRAW and mRAW files, there are plenty of Canon users who are willing to sacrifice resolution in order to gain more space on their SD cards as well as an increased burst rate – not to mention a speedier processing time.
Nikon introduced big-megapixel cameras, but forgot to provide smaller RAW files
At the beginning of 2012, Nikon has launched the D800, while a few months later the D800E has become available. The two cameras are very similar, both featuring a 36.3-megapixel full frame image sensor. The biggest difference between them is that the D800E does not feature an anti-aliasing sensor, so the images will be sharper, but more prone to moiré patterns.
Either way, an uncompressed 14-bit RAW file captured with the D800/D800E will have a file size of about 74.4MB. The size can be reduced to 57MB when shooting uncompressed 12-bit RAW, says Nikon.
Furthermore, lossless compressed 14-bit and 12-bit RAW files will have a size of about 41.3MB and 32.4MB, respectively.
Last but not least, lossy compressed 14-bit and 12-bit RAW files will be sized at 35.9MB and 29MB, respectively. This method may save space, but image quality is decreased as some data (usually in the lighter areas of a photo) is thrown away. Some photographers are agreeing that professionals have not purchased an expensive camera to capture low-quality photos at 36.3 megapixels, although convenience is more important for others.
As you can see, Nikon does not offer a lower-resolution file equivalent to Canon’s sRAW and mRAW, even though its cameras have sensors with more megapixels than the EOS-series shooters and such formats would make a bigger difference in this case.
The problem with larger files is that they influence the entire workflow for a photographer:
- the larger the files, the sooner the camera’s buffer is filled, so the burst capabilities of the camera is limited;
- larger files means that fewer photos can be stored on the memory cards in the camera;
- larger (and faster) primary and backup storage devices (hard drives) are recommended to handle those bigger files;
- opening, processing and converting larger RAW files on computers is slower.
As you can see, larger files require many upgrades if you don’t like a slower process. This is why there are many Nikon fans out there that are still using D700 for events, enjoying a fast-enough FX camera which produces small RAW files.
Well, 2014 came and it brought the D4s, which in turn introduced a “RAW S” file size, a first in Nikon’s line-up.
Nikon released the D4s camera with RAW S file size support
The Nikon D4s is now available for purchase as the company’s flagship DSLR. It features a 16.2-megapixel full frame sensor and impressive low-light capabilities.
A quick glance at the camera’s manual reveals that the device can shoot uncompressed / compressed (lossless or lossy) 12-bit / 14-bit RAW files. However, there is another addition to image formats and it goes by the name of “RAW S”.
According to Nikon, the D4s can shoot uncompressed lossy 12-bit RAW files at small resolution. This translates into a photo with 2464 x 1640 pixels or roughly 4-megapixel. The resulting (S) file would have about 13.1MB, whereas a 12-bit, but large (L) file would go to approximately 25.9MB.
Considering the fact that the size of 14-bit uncompressed RAW file captured with the D4s stands at about 33.6MB, wedding and action photographers have believed that they are in for a treat. However, an analysis made by RawDigger has concluded that the image quality is “too poor” to be worthwhile.
The conclusions of the Nikon RAW S file size test
According to RawDigger, the data for Nikon’s RAW-S is actually 11-bit instead of 12-bit. This should not be a major downside because the data is supposed to be uncompressed, but the problem is that it carries YCbCr data (similar to a JPEG file) instead of the RGB data used by RAW files.
In-camera white balance and tone curve are both “applied to the data”, meaning that there is limited post-processing edits that you can apply to these RAW files.
Moreover, color accuracy suffers significant losses in shadows, therefore the dynamic range prowess of the Nikon D4s is dramatically reduced in RAW S files.
Nikon’s own sRAW file format has some of the characteristics of a low-resolution JPEG file and it is not similar to what Canon is providing in sRAW and mRAW file formats.
Another reason why photographers are against using the new Nikon sRAW format is because the file size is not that smaller when compared to compressed lossy 12-bit RAW files, which are capable of retaining much more data.
As stated above, the sRAW has a size of 13.1MB in the D4s. However, the compressed lossy 12-bit RAW is sized at 14.1MB and users will still get 16.2-megapixel photos instead of 4-megapixel ones.
Why having a small RAW file size is still a good idea
The Nikon D4s does not have a big-megapixel sensor – it stands at 16.2 megapixels. The difference would be made in cameras such as the D800 and D800E, which feature 36.3-megapixel sensors.
It is worth pointing out the fact that Canon’s sRAW and mRAW file sizes are also losing some image quality when compared to full-sized RAW files. They “work” better than Nikon’s RAW S, but this technology is only at the beginning in FX-format cameras, so it can only get better in time.
Furthermore, we should mention that image quality is still a debatable thing. For example, some people prefer photos with richer colors, while some say that vivid colors are hurting their eyes. Numerous comparisons can be made, but only users will decide whether Nikon’s sRAW format is usable when it comes to providing decent-enough image quality or not.
The file size difference would be bigger in the D800 and D800E cameras, but it very unlikely that Nikon will bring it to these two shooters. However, it might make its way into the Nikon D800s.
Nikon D800s rumored to come packed with sRAW support
The Japanese company is rumored to replace the D800 and D800E with the D800s this summer. Nikon’s upcoming camera, which will feature a similar 36.3-megapixel sensor, is also said to offer sRAW file support.
As determined above, the sRAW format would make a bigger difference in high-megapixel DSLRs rather than in lower-megapixel shooters such as the D4s.
Although this is just a rumor, trusted sources are claiming that the D800s is indeed coming soon and will provide a RAW S option, allowing users to capture smaller resolution files that can still be post-processed.
Reducing the size of a RAW file is a tricky problem and a perfect solution may not even exist, so it is up to the individual user to decide which compromises he is willing to make.