The correct photo storage format – RAW vs. JPEG image file
JPEG files are compressed and finished images that have already been corrected fully automatically by the camera. These can be used directly, sent by e-mail, embedded on the website or can be printed as they are. Basically, everyone is familiar with this file format, mobile phone photos are usually JPEG files as well.
RAW files, on the other hand, cannot be used immediately and cannot be printed or uploaded to social media. Without a special program, these can even not be viewed on a computer. Just as old analogue film negatives used to be developed first, RAW files also have to be edited first. A well known RAW file format is the DNG, this abbreviation stands for "Digital Negative".
Real estate photography requires a relatively high dynamic range. Finally, the image is designed with light and shadow in post-processing. This requires the greatest possible latitude in image information. Insofar it is necessary to photograph in raw data format. The RAW format has the advantage that it contains a large part of the information captured by the camera’s sensor. This is also the reason why RAW files are so large compared to compressed JPEGs. The dynamic range and colour depth are much more extensive. A RAW file contains more nuances and allows lossless post-processing. Since the camera does not manipulate the images as much as in case of JPEGs, there is much more room for post-processing. Since JPEGs are irrevocably compressed, the colour and tone values cannot really be optimized in post-processing without a visible loss of quality. This is different for RAW files. Here, even over- or underexposed photos can be corrected and the white balance can be changed afterwards. Even the camera look is not final. For example, if the images are set to monochrome (black and white), colour images can still be generated from the RAW files. After final processing, the images can be converted to JPEG format (For Web) or TIFF format (For Print) at the very end of this process. However, RAWs are less but not really untouched files: Since various settings can still be made as how the files are saved on your memory card. Moreover, a RAW file never reflects the pure sensor information, as between the sensor and the memory card there are still AD-converters, processors and a software. For example, the Nikon D610 and D750 cameras use the exact same sensor, but the D750 still has better values and lower image noise at high ISO settings. The D810 again uses the same sensor as the Sony A7r, but the colour representation is slightly different and the Sony tends to increase edge noise while delivering a sharper image at the same time. Also, some RAW files are ISO invariant and others are not. RAW files should strictly speaking be named differently, because they are neither raw nor untreated... However, they come pretty close.
RAW data is the best that modern cameras can provide and should be preferred. With regard to the RAW settings, it is recommended that the following options be selected for how they will be saved:
Adobe RGB Colour space
lossless compressed RAW
Saved as 14-bit file
The Adobe colour space is the larger colour space. In addition, the classic sRGB colour space is only a subset of the Adobe RGB colour space, so that it can be easily reduced to sRGB at any time. If the camera also supports the ProPhoto RGB colour space, it should be embedded since it is the largest of all. On the other hand, converting sRGB into a larger colour space for gaining extra information will not work at all.
The RAW files should be stored as lossless compressed files. In contrast to uncompressed RAW, the files are much smaller. In addition, the compression is accompanied by no loss of quality, as the name suggests. The disadvantage is that older programs may not be able to read this RAW data because the compression codec changes and is updated from camera model to camera model. Since it is recommended to work with reasonably up-to-date software anyway, this problem will rarely occur in practice. Although there is also the option of lossy compression, which makes the files even smaller, but the image quality would suffer slightly.
RAW files can be saved with 12 or 14 bit. 14-bit files logically provide more tonal gradations and more colour nuances, so this option is qualitatively better. Some manufacturers also specify a 16-bit colour space and advertise with it, but this is only stored as 16-bit on the software side, since there are currently no sensors on the market that can actually deliver 16-bit at the hardware level. Even the Sony IMX161 sensor, which is used for example in the Fuji GFX 50r or the Hasselblad H6D-50c, only delivers 14-bit. The IMX461 (100 MP) and IMX411 (150 MP) sensors, which will soon be installed in PhaseOne's new medium format cameras, are no different. RAW files with 14-bit are thus the absolute maximum according to the current state of the art. RAW files with more than 14-bit have their origins in marketing; this should be kept in mind when deciding to purchase a camera. 16-bit RAW’s are not real. It is like opening a small and compressed JPEG in Photoshop, increasing the image size and saving it as 16 bit Tiff – It is possible but will not provide a better quality whatsoever.
Compared to a simple JPEG you can get the best quality out of a RAW file during post-processing:
RAW files can be recognized by the file extensions: .nef, .cr2, .dng, .orf, and .arw. Unfortunately, every camera manufacturer has its own RAW file formats, so that the multitude of file extensions can get a little confusing. Fortunately, almost all of them can be opened and edited in modern image editing programs such as Adobe Photoshop CC or Lightroom. According to the case that only an older version of Photoshop or Lightroom is available but a new camera model is used, the files may not be recognized. However, this problem can be easily solved. Adobe offer the "DNG Converter" for free download. This program can convert all RAW files into the DNG RAW file format, which is supported by all Lightroom versions and all Photoshop versions starting with CS6. The conversion takes place without any loss of quality and thus enables RAW processing with older program versions. In addition to the comparatively price-intensive programs such as Adobe Lightroom or CaptureOne, there are also cheaper alternatives such as the Luminar program from Skylum. Of course there is also freeware: RAW Therapee or Darktable should be enough as examples. This may sound a bit much and complicated for the beginner, but for real estate photography RAW files are essential if certain quality standards are to be achieved. This does not mean that intensive image processing is always necessary, but at least a colour cast should be removed and the shadows lightened with a few clicks. With RAW files and the corresponding program, all these corrections can be made in two seconds and applied to subsequent images of the same object. Initially it is also possible to set the camera to save RAW files and JPEGs at the same time. In this way, the JPEGs can be used immediately and the RAWs are still available if post-processing is deemed useful.
