Have a deep understanding of RAW format.

Unfortunately, many readers have to face some bigger problems after choosing the RAW format. RAW file is very large, and not all post-processing software can open it directly. Camera manufacturers are unwilling to choose the same format to save the original image information of the camera, which is really a nerve-racking thing and brings us a lot of inconvenience. But once we solve these problems and get used to shooting and processing in RAW format, we will find that the actual situation is not as painful as we thought at first, and your photography level will enter a new level in one fell swoop. We will explain the reason and necessity of shooting with RAW from the beginning, and answer all questions related to RAW.

As a photographer, RAW format is the only choice for Charles to shoot.

A deep understanding of RAW: the characteristics of 1 Original format

Before you start shooting, find out what the RAW format is. What is the RAW format?

Original English translation of raw materials. To understand the RAW format, we need to understand the actual imaging process of digital cameras. After we press the shutter, the light shines on the photosensitive element of the camera through the lens, and the photosensitive element converts it into an electrical signal to form image data. In short, these electronic signals are the main raw materials of the original documents.

16 bit image contains more tone information, and the same processing operation can get better results.

The key to distinguish RAW format from JPEG format is to process these electronic signals after acquisition. RAW file is composed of the original electronic signals and related basic information recorded by photosensitive elements, and it is directly saved to the memory card without any compression and processing. Before the JPEG file is saved to the memory card, the original electronic signal recorded by the photosensitive element has been processed by the processor inside the camera according to the settings such as white balance and picture style we chose. The processing result is converted into JPEG format and then written into the memory card. In other words, no matter which format we use to shoot the camera, we need to collect the original picture data. We decide whether to give these original data to the camera as JPEG format or save them as RAW format for our own processing.

Are all the original documents the same?

No, most of the confusion around the RAW format is due to this problem. Unlike JPEG format, RAW format has no uniform standard. Each major manufacturer has its own way, and the format of RAW file used is different, even the standards used by different cameras of the same manufacturer are different. For example, although the RAW files of Canon digital SLR all have the suffix of .cr2, there are still some small differences between EOS 1 100D and EOS 7D.

The format of the RAW file used by the same camera will not change, so if you find a conversion software, it will not affect your work. However, if we need to process files from multiple cameras of different models, or switch to a new camera without updating the corresponding software version, we can appreciate the inconvenience caused by this difference, and you will not be able to convert the photo format.

In this chaotic situation, DNG format is the only exception. It is an open file format developed by Adobe, and any digital camera manufacturer can choose it. But among all the mainstream digital SLR camera manufacturers, only Pentax has provided this format in its own camera. However, even if we choose cameras from other manufacturers, DNG format can still bring us convenience. After converting the camera's original Raw format into DNG format through the conversion tool provided by Adobe, we can use the Adobe Camera Raw provided by the old Photoshop to open the RAW file taken by the new digital camera.

Why can I only preview RAW files stored on my computer through special software?

RAW file is a packet file, not an image file. Our computer doesn't know how to interpret this kind of data packet. Unlike standard formats such as JPEG, RAW files do not contain information needed for computer decoding. I think the following analogy may help you understand this problem: JPEG format is like an article, with clear division of words and sentences and neat punctuation; Although the RAW format also contains the same article, all the words in it are scattered into basic strokes and combined together in disorder. So we can't browse at all.

Is the RAW format an uncompressed format?

Part of it is. In order to reduce the size of image files, people have designed various complicated compression algorithms. There is an important difference between these algorithms, lossy and lossless.

As the name implies, lossy compression means that some image data will be discarded during compression. But after discarding this information, you can get a much smaller file than lossless compression. Some RAW formats, such as Nikon's. NEF format, can be saved in this way, so that you can get a file that takes up less space. However, this will lead to a decline in image quality, especially in parts with smooth tone transitions such as the sky.

All JPEG files use lossy compression algorithm. JPEG files will provide a picture quality setting for us to choose when saving. The lower the image quality we choose, the more image data we discard and the smaller the image file we get. On the contrary, JPEG files with higher image quality are larger than those with lower image quality. If we only save the obtained image file once, the degradation of image quality caused by the saving process is almost imperceptible. However, with the increase of saving times, more and more image data will be lost, so the overall image quality will decline more sharply. Lossless compression format contains all the data in the original file, but the generated file size will also occupy more storage space. Most RAW formats are compressed in this way to ensure that the image information is not lost during repeated storage, so the image quality is higher.

These two compression modes are set by the manufacturer, so we can't choose them in the camera, but in any case, RAW format files contain much more information than JPEG files.

What's the difference between 8 bits of RAW file, 12 bits, 14 bits and 16 bits?

Every photo we take consists of different tones from black to white, and? Bit? It represents the hue range between black and white. The bigger the bit, the richer the tone between black and white. All JPEG format files are 8-bit image files, so there are only 256 tone changes between black and white. RAW format files are mostly 12 bits or 14 bits, and contain at least 4096 tone changes between black and white. It is generally believed that to express a soft and natural picture, at least about 250 tones are needed, so an 8-bit image file containing 256 tone changes can meet the needs in most cases.

But when we use color scale or curve command to adjust photos in Photoshop, the problem arises. This command will compress or expand the tone range of the photo, resulting in a gap in the middle of the image histogram, as shown on the previous page. At this time, there will be defects such as ribbons and color blocks in the picture. This phenomenon is particularly obvious in areas with smooth tone transition such as the sky. RAW files have provided us with richer colors from the beginning, and even if we do more extreme operations, similar problems mentioned above will not occur. This is especially obvious when repairing photos with inaccurate exposure. Even if the exposure is greatly adjusted, the fine texture can be preserved on the photos.

Photoshop cannot directly edit 12 or 14 bit files. Most RAW editing or conversion software provides two options when outputting RAW to other common image formats: 8-bit and 16-bit.

A deep understanding of RAW 2. Conversion of RAW format

Although this process is short, it can bring you great convenience. What software should I use to open and edit my RAW files?

There are countless RAW conversion software to choose from, which one is the most suitable depends on the number of your films, the content of your works and the degree of post-processing.

Most digital cameras provide users with camera-specific RAW conversion software, which can be used as a starting point for us to learn RAW processing. However, most of these softwares have some shortcomings, such as low efficiency, outdated technology and limited functions.

If you need to make more professional adjustments to RAW files, such as highlight and shadow restoration, then you should choose professional processing software, such as Adobe Camera Raw(ACR). ACR is an integrated conversion software in Photoshop CS series, which provides very rich adjustment options. If used properly, it can even replace Photoshop, and you can do most of the photo processing in ACR.

At present, the latest decontamination tool provided by ACR 6.x is similar to the repair brush tool in Photoshop, which can be used to remove the photoreceptor stains and other defects in pictures; The black-and-white photo conversion function in HSL/ grayscale is more powerful than that in Photoshop. Although other old versions of ACR are not as powerful as the new version, it is still a RAW conversion software suitable for most photographers because of its function and ease of use.

If you often need to process a large number of RAW image files, you can also consider professional RAW processing software such as Adobe Photoshop Lightroom, Apple Aperture or Capture One Express/Pro 6. Compared with the original software produced by Adobe Camera Raw and camera manufacturers, this kind of software is not only powerful and rich in functions, but also provides a more flexible and easy-to-use workflow. If you are used to the interface and functions of Photoshop, Lightroom is undoubtedly the easiest software of the three, which is basically Adobe Camera Raw with improved workflow.

Adobe DNG converter is a very practical software. With its help, the old users of ACR can also open RAW files shot by new digital cameras.

I can't open the RAW file generated by the camera in Photoshop. What should I do?

This is a common problem. Camera manufacturers will improve their own RAW file algorithm while producing new cameras, which leads to incompatibility with software. At this time, we can open these files with random software, but it also means that we must master a new way to use the software. However, considering that most of the functions of the random software mentioned above can't be compared with Adobe Camera Raw, it is really reluctant.

Upgrading Adobe Camera Raw is also an optional solution, but it has limitations. The latest version of ACR supporting new cameras can only be compatible with the latest version of Photoshop in the same period. In other words, if you want to upgrade your version of Adobe Camera Raw to the latest version 6.6 when writing this article, you must have Photoshop CS5.

Considering that not everyone has the strength to keep up with Adobe's upgrade, there is still a way to download the latest version of DNG conversion software and convert RAW files shot by cameras into open RAW formats. DNG。

Since Photoshop CS3, ACR has provided complete black-and-white conversion options.

A deep understanding of RAW 3. Use of raw format

After understanding the theoretical basis, let's see what RAW can do for us. Apart from the advantages, what are the advantages and disadvantages of shooting in RAW format? There are many reasons for taking pictures in RAW format, but compared with RAW format, JPEG format is not completely without benefits.

RAW has higher picture quality and provides more post-production space. Most image settings of the camera, such as white balance, sharpness, saturation, etc. , will not be directly applied to RAW files, we can adjust these parameters more finely on the computer. Compared with JPEG files, RAW files contain more image information and richer colors. In other words, the tone transition in the RAW file is smoother, and even if it is greatly adjusted, it is not easy to have defects such as color splitting or pixelation. This is especially important for pictures with similar tones or colors. This advantage is not without cost. RAW files are usually three to five times the size of high-quality JPEG files, so fewer files can be saved on the same size memory card.

Different from JPEG files, the browsing and output of RAW files are very troublesome and must be carried out with the help of special conversion software. In other words, before sharing or outputting the shooting results, we first need to convert them into common file formats. At this time, we have to face another most annoying problem of RAW files: we need to spend more time adjusting the works, and the endless setting options in Adobe Camera Raw and other software make this long process worse.

What is the biggest advantage of RAW files compared with JEPG files?

The extra highlights and dark information contained in the RAW file can perfectly reproduce all the details in high-contrast scenes such as sunsets.

The biggest advantage of RAW file is that it saves more details of highlights and dark tones, and provides better white balance control. Compared with JPEG files, RAW format contains more extra information, so it is more comfortable to record high-contrast scenes.

Although the photos taken in JPEG format can also restore the dark details through post-processing, it will cause obvious noise. Using RAW files can restore dark details while still maintaining a relatively high picture quality. Similarly, using the highlight/shadow tools provided in Photoshop, we can also recover limited details from the highlights of JPEG files, and more details can be recovered if shooting in RAW format. In a word, the more original information a file contains, the richer the content that the RAW conversion software can restore.

With the RAW format, we can also change the white balance settings of photos at will after shooting. Although for JPEG images, we can also control the color of photos through the color balance function, compared with the adjustment results of RAW in Adobe Camera, it is really childish, and the processing process will also destroy the original image information of the file.

Professional photographers shoot in RAW format, right?

Not exactly. Although most professional photographers do shoot in RAW format, there are many exceptions. Some photographers think that the speed and convenience provided by JPEG format are more important than the image quality provided by RAW format. This is true for sports photographers and some news photographers, because they need to take, edit and upload photos in a short time.

In this case, how can I set the camera to RAW shooting mode?

Most cameras shoot in JPEG format by default, so we have to set it to RAW shooting mode ourselves. How to operate depends on the camera model. Most digital SLR cameras and micro-system cameras can set the storage format of photos through menus such as image quality. See the camera manual for details. Some cameras sold in recent years provide buttons specially set for shooting format. After setting the shooting format, you can shoot normally according to your usual habits. Some Canon digital SLR cameras? After EOS 60D? Provide three storage options: RAW, MRAW and SRAW, corresponding to different photo resolutions. RAW is a full resolution format. Take EOS 7D as an example, and the file it gets is18 million pixels. When set to MRAW, the file is 6.5438+million pixels, and when set to SRAW, the file is 4.5 million pixels. If you don't need to enlarge photos and want to have the advantages of RAW format at the same time, you can use RAW format with lower resolution to save memory card space. Digital cameras after Nikon D7000 also provide rich RAW format settings, allowing us to adjust the compression ratio and bit depth of the image. Remember what we said before, the higher the bit depth, the larger the file.

The RAW format in the above picture is generally set by the image quality option in the menu, and some cameras also provide special setting buttons.

When shooting in RAW format, which parameter settings on the camera can be ignored? What should I pay attention to?

When shooting in RAW format, we can adjust many parameters of the image on the computer, which has been mentioned many times. But this does not mean that we should ignore these parameters when shooting, especially exposure. Even if it is a RAW file, the timbre information that can be recorded is still limited, so it should be as accurate as possible when exposed.

White balance settings should be equally accurate for two reasons. First of all, using the correct white balance setting can save post-processing time. Most RAW conversion software will take the white balance setting built into the photo as the default value when processing. Secondly, the white balance setting we choose will affect the tone range of the photo, and then affect the exposure. Other settings, such as sharpening, noise reduction and color space, are only stored with the original image information in the form of labels, and will not directly affect the file content. If we use the RAW processing software provided by the camera manufacturer to open the photographed photo file, these settings will be loaded as default values, but we can also change their settings as needed.

At this time, we should also pay attention to the long-time exposure noise reduction function. Whether using RAW format or JPEG format, its function is obvious. This function is to shoot an all-black picture after a long exposure, which can be used as a reference to reduce the noise of long exposure.

A deep understanding of RAW 4. Preservation of original documents and advanced skills.

In the Workflow Options panel, you can set the file color bit depth to 8 bits or 16 bits.

What is the difference between different file formats (such as JEPG and TIFF) provided when saving images? What is the difference between 8-bit, 16-bit and other different color depths? Which format is best for saving the adjustment results of RAW files?

Which format to choose depends on the final use of the photo. TIFF files can be saved repeatedly without worrying about quality problems, while JPEG format will cause a certain degree of file information loss and reduce quality every time it is saved. If we have completed all necessary operations in the process of RAW conversion and the exported files are only used for browsing, output or communication, then JPEG format can be used. However, if we want to continue to make more complicated adjustments to the photos in the main interface of Photoshop, only by saving the files in TIFF format can we ensure that the image quality will not decrease.

When saving TIFF files, we need to choose 8-bit or 16-bit color depth. As mentioned earlier, the 16 bit file contains more tone information, but this format is not completely compatible with all adjustment commands in most software. Photoshop CS5 can make full use of this extra tonal information, but if you are using an earlier version of Photoshop CS series, then an 8-bit TIFF file is the safest choice, so you can use all the adjustment commands and filters provided by the software.

Isn't saving RAW files in JPEG format the same as shooting directly in JPEG format? I don't understand why it's unnecessary.

If you just open the RAW file in Adobe Camera Raw and save it directly as a JPEG file by applying the default adjustment settings, it is really no different from the JPEG file obtained directly from the camera. But doing so loses the meaning of using RAW format. We use RAW format to make more delicate adjustments according to the different characteristics of photos. Even with the default settings, JPEG files converted from RAW files in some extreme light environments are better than JPEG files directly converted from cameras in noise performance, highlights and dark details.

I found that every RAW file is a file with the same name and suffix after ACR adjustment. Xmp will appear in the folder? What's going on here?

After adjusting the image with ACR, you will find one. Xmp file with the same name in the folder where the original file is located.

Except DNG file, ACR will not modify the original information contained in any RAW file, so we must find a new way to save the adjustment and setting operation of the file, so there is a file with the same name in the folder. When we click the Save Image, Open Image or Finish button in ACR, this attachment will be automatically generated in the folder. The next time you open the adjusted RAW file, ACR will automatically read the operation setting information saved in it. For them, the only thing we need to pay attention to is to move, copy or back up RAW files, or continue the last adjustment operation on other computers. Otherwise, the next time we open these files in ACR or Photoshop Lightroom, they will remain in the original state when they are not edited, so don't delete them as viruses.

If we want to save the adjustment information, we must pay attention to the attached file with the same name when moving or copying files, or put the whole folder? One pot end? . However, the safest way is to copy or move files in Adobe Bridge, and the program will automatically copy or move attached files with the same name. Like the dilemma faced by RAW files, different software vendors save the adjustment and setting information of RAW files in different ways, so this. Xmp files can only be recognized by Adobe's RAW adjustment software.

What did you say before? Nondestructive adjustment? What the hell does this mean?

When we save the edited file in JPEG format or TIFF format without layers, the file will be rewritten. After closing the file, all the original data will be lost. When we edit the RAW file, all the settings will be saved as attachments, and the original file information will not be affected. In fact, there are many ways to realize lossless adjustment. In addition to generating an attached file by software to record the previous operations, you can also directly save the settings in the file.

Adobe Camera Raw can not only lossless adjust Raw files, but also lossless adjust JPEG or TIFF files in the same way, and save the adjustment settings in an attachment file with the same name, so that we can go back and make adjustments again at any time. Of course, if we use other software to edit and overwrite the original document in JPEG or TIFF format, then our setup file will lose its meaning, so it is better to use the same software to adjust a photo.

The above is all the content I shared that I know the RAW format. Welcome to read the collection!