HDR - Shooting and processing photos. What gives the HDR mode in the smartphone camera
More and more people ask me how I get such HDR photos and why I have such a strange processing "algorithm". I decided to make a separate topic in which I will try to answer these questions.
1. Theory
What is HDR and why is it needed?
HDR - High Dynamic Range, or in Russian Wide Dynamic Coverage. dynamic range measured in " exposition steps" (EV). An exposure shift of 1 EV means a 2x change in the amount of light hitting the film or digital matrix. For example, if the shooting parameters calculated by the camera are 1/50 sec (shutter speed) and f/8 (aperture), then +1 eV exposure compensation will result in shooting at 1/25 sec and f/8 in aperture priority mode, or 1/50 sec and f/5.6 in shutter priority mode.
Very often I see photographs with broken highlights and failed shadows, and almost always the authors of these photos claim that " so it was". The problem is that the dynamic range ( DD) of the human eye (the ability to see details in both highlights and shadows at the same time) is (for different people in different ways) about 20 steps, which significantly exceeds the DD of digital camera sensors.
It's sad, but DD Canon"ov is a little behind Nikon"ov. In principle, this is not "fatal" if you shoot several frames for HDR"a, which is usually done. But, having a camera with a wide aperture, you can get a pretty high-quality pseudo-HDR from one frame and at least a couple of my last shots from Prague can serve as confirmation of this.
Why is HDR needed? Then, in order for the photo to be the same as the shot scene was seen by the eyes of the photographer, i.e. details were visible both in the brightest areas and in the darkest.
HDR "a has both fans and opponents ... some people like such photos, but some do not. In my opinion, high-quality HDR looks gorgeous! The undoubted master in this area is Trey Ratcliff. By the way, from birth he is blind in one eye, but this does not bother him in any way!
HDR or not HDR, that is the question! If the scene being shot has a lot of contrast in highlights and shadows, then it makes sense to take several photos with different exposures for the HDR assembly. Such an example could be a night city or abandoned buildings. If the dynamic range of the scene is not large, then HDR may be superfluous.
2. Practice
What is needed to create an HDR photo? It is necessary to find an interesting place and grab a tripod if handheld shooting is difficult due to slow shutter speeds. Many digital cameras can shoot what is called Exposure Bracketing, which will allow you to shoot a series of frames at different shutter speeds, the first of which (depending on the camera settings) will be very dark, the middle one will be normal and the last one will be very light.
I read somewhere that it is desirable for HDR image assembly programs to have, say, 5 bracketing frames in one stop steps, rather than 3 frames, but in 2 steps. Since the exposure step on my D800 is 1EV, I usually shoot 5 frames of bracketing.
For those who shoot Nikon it might be interesting to watch a video on how to set up a camera that will shoot the entire bracketing series by itself with a single press of the shutter button. This trick is indispensable when shooting at night at slow shutter speeds - even if you shoot from a tripod, the constant pressure of your finger on the shutter button at shutter speeds of 20-30 seconds can lead to a slight shift / shake of the camera and a damaged frame.
If the spread between light and shadows is large, then sometimes I shoot 9 frames in order to "capture" as useful information as possible, such as in the next two photos.
3. Processing
For those who speak English, I want to advise you to read the book, I read a lot of interesting things in it. Concerning " What is the best build program to use?"I think many will agree that Photomatix Pro is the best. Photomatix can work both independently and as a plug-in for LightRoom"a and Aperture. A big plus of this program is the ability to use presets, of which there are a sufficient number in the open spaces Internet.
I will try to describe my processing step by step.
1) All RAW "s (if someone else shoots in JPEG" ah - quit this business and switch to RAW "s) I import into LightRoom;
2) and setting the same White Balance for all frames (sometimes there is a slight discrepancy in WB);
3) Sometimes on some frames I move the Highlights & Shadows sliders;
4) I send all frames to Photomatics. 
If HDR was made from several frames and there are moving objects, I control how well Photomatics "suppressed ghosts" (Ghost removal). There is an opportunity to manually specify "problematic" areas and usually Photomatics "crushes ghosts" very well.
5) There I get a result that suits me, I save it. LightRoom automatically "clings" the result, which is almost immediately "sent" to Photoshop;
6) In Photoshop I clean various "garbage", I correct the geometry;
7) I use it very often Nik Color Effect Pro -> tonal contrast and Darken&Lighten Center;
8) I often apply noise reduction to the sky Nik Dfine;
9) Save and return to LightRoom;
10) "Adjustment brushes" in LightRoom" are very powerful local correction tools. Therefore, I almost always finalize the frame in LightRoom "e using corrective brushes in various modes (darkening, brightening, Highlights, Shadows, Clarity (both plus and minus), Sharpness and Noise). I have a lot with them easier to work with than with adjustment layers and masks in Photoshop.
11) I export the result (usually 1400pix in width), look at it and periodically find some flaws, return to LightRoom or Photoshop, eliminate them, export again, look and ... and often this process is "look-see-finish "It can drag on for a long time, until everything suits me.
12) Very often I wait until the next day and very often I finish something the next day.
Well, here is my process of processing photos ;-)
4. Video footage
This section will be of interest to those who are "friends" with English and those who want to "deepen" their knowledge in the field of HDR. I highly recommend watching all the videos.
All successful experiments in the field of HDR !!!
One of the most interesting and useful image processing techniques is dynamic range expansion. This technique is called HDR (High Dynamic Range). Despite all the advantages of this technique, it is often criticized. All criticism is poured on HDR photography for several reasons. Most often - this is the wrong use of this technique, excessive enhancement of detail and saturation. Also, sometimes people just don't like the creativity used in the realization of the shot and they attribute their dissatisfaction to the technique in general, and HDR can be different. Sometimes the dynamic range expands quite naturally and unobtrusively. Then not everyone will notice that the photo consists of several shots taken with different exposures.
Let's take a look at some of the accusations against HDR.
1. HDR doesn't look realistic
Most often, people are unhappy with the fact that HDR does not look realistic. Search results for the query “HDR” are replete with pictures that ripple in the gases. The thing is that unfortunate photographers turn all the settings to the maximum and the photo begins to convey details and colors that should not be in it. It's all about the lack of measure and aesthetic taste of those who create such works.
If the dynamic range is expanded correctly, if the balance between detail, contrast and natural color is maintained, then such a picture will look very nice and harmonious.
The fact is that the human eye sees in a much larger dynamic range than the camera matrix. The expansion of the dynamic range in photography is primarily necessary to bring the pictures to the form as we would see the picture live.
2. HDR is a fake of what the camera shoots.
Some overly biased photographers say that HDR processing distorts the true look of the photo. In fact, such disputes arise at the border of styles. Photojournalists will not be able to do such processing due to the specifics of shooting. They don't need it. The whole essence of their work in the transfer of information. If you are into landscape or architectural photography, HDR will help to enhance the beauty of the picture. It will increase the amount of detail visible to the naked eye and show how beautiful and diverse the world around is.
HDR began to emerge in the era of film photography. When developing frames, it was possible to overexpose or underexpose some areas and thereby increase the dynamic range. Also, the use of a gradient or polarizing filter also serves to expand the dynamic range. Only this is done not at the software level, but at the hardware level. But, for some reason, no one says that the use of these techniques is a scam with the naturalness of photography.
3. HDR makes everything more attractive
Now HDR is becoming more common thanks to various programs for mobile devices. It is also built into many cameras. But there are people who do not have devices with this functionality, who try to process each of their shots using the HDR technique. They believe that such photos look more juicy, spectacular and interesting. In fact, you should not constantly apply this effect. Only shots with deep shadow gaps or strong highlights, photos with colorful textures require a slight increase in dynamic range. In such cases, the frame will become more informative and enjoyable. If you apply the HDR effect constantly and without a sense of proportion, then nothing good will come of it.
4. Nobody likes HDR
There are separate communities of opponents of HDR. People formulate a lot of conflicting opinions, but a search for HDR shows that many more people love it. The most interesting thing is that if the expansion of the dynamic range is carried out qualitatively, then no one will notice it. The picture will look quite natural and will not stand out from other photos.
5. You need a tripod to create HDR
Due to the fact that you need to create several shots with different exposures, a tripod will greatly facilitate the work, however, you can safely take photos by hand. The main thing is not to leave the place between shots. Light camera movement is compensated by auto-alignment in graphic editors. This procedure is very fast and precise, so there is no special need for a tripod. Exposure bracketing will allow you to take frames quickly and with minimal error.
6. HDR Presets Work Better Than Manual Adjustment
More often than not, photo editor presets are the starting point for manual editing. If they look good with one shot, it doesn't mean that all the scenes in it will turn out the same way. A preset is usually used to bring in the basic settings to suit a particular processing style, but then most of the settings are tweaked by hand to give the best look.
The standard preset very often just spoils the picture and needs to be brought to a normal look. Artifacts and excessively dark or light areas may appear. The contrast may be too much. This will have to be corrected by hand. Each photo needs to be approached individually, and presets can be great helpers, but they should not be completely relied upon.
7. Professional HDR software is better than humans
Many amateur photographers prefer to create HDR with the click of a magic button in special plugins or specialized programs such as Photomatix. To understand the difference between auto-creation and manual HDR, we need to look at a real-world example.
Due to the backlight, the foreground turned out to be very dark and in order to return the detail to it, you will have to use the HDR processing method. Automatic creation led to the appearance of a mediocre picture with many shortcomings. Only by manually working with curves, contrast, colors and sharpness can you get a really high-quality result.
Conclusion
In the right hands, the HDR processing technique produces stunning images that look real and free of many of the drawbacks associated with dips in shadows or blowouts in highlights. There is no need to be biased towards technology in general. If you do not like a particular picture, then claims can only be addressed to the person who processed it.
If you spend enough time on photo sites, you've probably noticed a lot of photos with deliberately bright images. This is an HDR photo. Let's see what this term means.
HDR (High Dynamic Range) is an imaging technique that allows for a wider dynamic range of exposure than would be possible with conventional photographic methods available. HDR is commonly used for landscape photography to emphasize the visual impact of light and shadow over a large range.
by Helmut R. Kahr
No person can be credited with the invention of HDR photography. It is rather an evolution in photography that began with Ansel Adams' zone system and continues all the way to modern photo post-processing programs.
During the reign of film photography, the cut-off range was added by altering the negatives when printed. They darkened or brightened the necessary places in the image in order to eventually get a picture well worked out in all problem areas.
by Ansel Adams. Falls Nevada. Rainbow. Yosemite National Park. California. 1946.
When digital photography took over the world, users very quickly figured out how to increase the dynamic range of an image by taking the same frame with multiple exposures. You can love or even hate HDR photography, but there is no doubt that it already firmly occupies a certain niche today. 
by Marc Perrella
This type of photographic image is characterized by “heavy” color saturation, a strong halo along the border of contrasting shades and a general surreal look at the image. Most viewers, having seen enough HDR shots, say that: “It looks like a painting!” It could be considered a compliment if it were not added: "This is not a photograph."
Meanwhile, there are more and more photographers who often use HDR in their work to create a big effect. As with any art form, do not overdo it, then even the acrimonious criticism that HDR destroys photography as an art form will not be taken so seriously by those who are just taking their first steps in mastering photography.
by Basile Francesco
It is important to know that the increased brightness and expressiveness of the image is not a prerequisite for the HDR process. The term HDR applies to all images in which . The original goal of HDR photography is to look at the world around you in terms of the fantasy of the image, while remaining in the range of balance between light and shadow.
by Danny Xeero
Traditional HDR is achieved by taking multiple frames with different exposures. You need to take 3-7 photos, each with a slightly different shutter speed. After the received images are combined into a single one, the result is that the dynamic range becomes much greater than the most modern digital technology can provide, which sometimes cannot reproduce even the semblance of what the human eye sees.
HDR photos themselves are designed to bring the digital image closer in saturation and detail in highlights and shadows to how a person sees and perceives the surroundings. And as in any creative process, a lot depends on the taste of the photographer, on his preparedness and ability to distinguish a good photo from a bad one. In essence, you need to know when you can use HDR without harming the final result.
Landscapes HDR photo
Whenever a photographer is dealing with an expansive mother nature scene, it's an excuse to take multiple shots of the same scene at different exposures. When there is a large contrast difference between the sky and the ground in the landscape, it creates a problem for the camera, which cannot decipher how to properly process the image that entered the viewfinder due to conflicting data. By exposing first on the ground (water) and then on the sky, the photographer, when overlaying, will receive a more truthful image in the dynamic range as a result.
by Karl Williams
Lighting
When you have to shoot in low light or a backlit subject, this can result in an image that is darker than you hoped. In this case, the use of HDR can be the best.
When not to use HDR
Just as there are situations to make the best use of HDR, there are times when you shouldn't use it at all.
Traffic
There are several reasons why objects in motion don't translate well into HDR. If your subject is running or running or moving, say, on horseback using the HDR technique, you will most likely end up with a blurry shot. Why? It is because the object is moving. Remember that for HDR you need to take at least three shots? In this case, the moving object in a fraction of a second will be in a completely different place in each subsequent image. With a high degree of probability, when combined, blur will occur.
Bright colors
If the scene you are shooting has too many dark areas or too many bright areas, HDR will "invent" some colors on its own in those areas where it is not enough. And if there are many bright colors, then with a high degree of probability it will lighten, “wash” them.
HDR can be a great tool for getting artistically interesting photos, as well as technically better ones when you have to shoot in bright sunlight with dark (failed) shadows. How this tool is used depends largely on the photographer. It is necessary to try, experiment and learn to translate new skills into reality in order to raise the level of your skill and be able to find a way out of seemingly hopeless situations from the point of view of photography.
Any person who acquires a camera and begins to engage in photography goes through several stages of formation. First, the amateur photographer studies his camera, gets used to it, takes pictures using the built-in modes, and then switches completely to the intelligent manual mode, where the creative abilities of a person and the capabilities of the camera are revealed. During this period, the camera, as a rule, is set to settings that save the image in Further, gaining experience, gradually overcomes the first stages of professionalism (we will not describe all the characteristics of this stage) and, undoubtedly, begins to notice that photography is a limitless field for creativity. that using a camera you can literally “write” the history of time, marking moments.
The photographer does not pass by such an interesting topic as HDR photography(hdr technology). What is it and why, having once tried to shoot in order to create an HDR photograph, photo artists are increasingly resorting to this method.
HDR photography- this is a combination of photographs with different exposures (or shutter speeds), taken at the same time, preferably with the same camera, into one shot. To put it even more simply, HDR photography is a cross between an overexposed shot with a normal exposure and a dark photo. HDR photography is a photo with a higher dynamic range, which makes the photo attractive to the observer. As a result, you can get a photo that strikes with its realism and something incredible, since all the shadows are clearly visible in the photo, it is contrasting, all shades and colors are drawn. If a normal photo does not show shadows in dark areas, and the sky looks like a solid white-gray or blue background, thencreating HDR, You get a picture in which you can see literally everything, any shade. And the sky, even if it is without clouds,HDR photosnevertheless, it will contain shades of different saturation, which will please not only the photographer, but also those who simply see such a photo.
In order to take pictures suitable for HDR, you do not need to possess (although it is desirable, but this will come later, when you understand the whole process, how to take pictures and whether you need it), both ordinary and more advanced models are enough, which can be purchased almost in any electronics store. In addition to the camera is essential. Again, at the first stages, the simplest one is quite suitable, there is no need to chase professional equipment. A tripod is needed in order to shoot several frames from one point, in order to combine them into one in the future. And if you shoot for HDR without a tripod, it can be difficult to combine photos (although if you own Photoshop or another graphics editor, this problem can be partially solved).
The easiest way create pictures for HDR next: you need to select the exposure settings in the camera menu, set it to the extreme value - to take a picture, to the zero position - to take a picture, to the extreme right position - to take a picture. The number of photos may be more (not only the extreme-middle-extreme exposure settings are possible, but also intermediate ones).
After the pictures are taken, there are several ways: use graphic editors to create HDR, which is not very easy and not always clear for a beginner, or you can use special programs that automatically merge the received pictures into one, allow the user to make some adjustments for alignment photo, editing color, saturation, etc., then view the finished result and save it.
Some cameras have a function that allows you to immediately take several pictures with different exposures (bracketing), which is incredibly practical and convenient, quite simple and understandable.
Here are some programs that photographers use to create HDR photos:
- easy HDR,
- Photomatix,
- lightroom,
- HDR Effect Pro,
- Dynamic Photo HDR and others.
Sometimes, with the help of these programs, you can make a pseudo hdr, i.e. load into the editor not a group of images, but just one and start editing it. By the way, if your camera supports
The cameras of the Pixel and Nexus smartphones have never been anything special, but over the past four years they have taken a powerful leap forward and now occupy the first lines of the ratings. Why did it happen? Because Google has implemented a software post-processing engine called HDR+. In this article, we will explain how it works and how to enable HDR+ on your smartphone, regardless of brand.
What is HDR
To fully understand how HDR+ works, you will first need to understand regular HDR.
The main problem of all smartphone cameras is the small size of the matrix (or rather, photocells) and, as a result, insufficient coverage of the dynamic range. To correct this drawback, the HDR (High-Dynamic Range) algorithm was developed, the principle of which is as follows: the camera takes a frame with a standard exposure level for a given scene, then takes an underexposed frame, on which only overexposed areas of the original image will be clearly visible, then An overexposed image in which only the dark details of the original image are visible, and everything else is overexposed. Further, the images are superimposed on each other and combined using special algorithms, the quality of which depends on the manufacturer of the camera software. The result is a picture with good detail in both the shadows and the brighter areas.
The disadvantages of HDR are obvious: a long shooting time leads to the fact that moving objects caught in the frame will double, and even a little shaking will blur the picture.
What is HDR+
Smart heads have come up with an algorithm devoid of the shortcomings of HDR. However, it has only one name in common with HDR.
HDR+ stands for High-Dynamic Range + Low Noise. He received his fame for a number of outstanding features: the algorithm is able to eliminate noise with virtually no loss of detail, improve the quality of color reproduction, which is extremely important in poor lighting and at the edges of the frame, at the same time it greatly expands the dynamic range of photography. HDR +, unlike standard HDR, is almost not afraid of smartphone shaking and movement in the frame.
The first HDR+-enabled smartphone was the Nexus 5. Due to not the best white balance and a small aperture (f2.4), the camera of this smartphone was considered nothing more than a strong middling. Everything changed with the release of the Android 4.4.2 update. It was it that brought with it support for the HDR + mode and the amazing quality of night shots. Although they were not very bright across the entire field of the frame, thanks to HDR + they practically did not contain noise while maintaining small details and had excellent (for smartphones in 2013) color reproduction.
History of HDR+
How does a company that has never done a camera come up with an algorithm that works wonders using conventional, by flagship standards, Nexus and Pixel cameras?
It all started in 2011, when Sebastian Thrun, CEO of Google X (now just X), was looking for a camera for Google Glass augmented reality goggles. The weight and size requirements were very strict. The size of the camera matrix had to be even smaller than in smartphones, which would have an extremely bad effect on the dynamic range and would lead to a lot of noise in the photo.
There was only one way out - to try to improve the photo programmatically, using algorithms. This task was to be solved by Marc Levoy, a lecturer in the computer science department at Stanford University, an expert in the field of computational photography. He focused on software-based image capture and processing technology.
Mark formed a team known as Gcam, which began to study the Image Fusion method (fusion of images), based on combining a series of images into one frame. Photos processed using this method turned out to be brighter and sharper, with a small amount of noise. In 2013 technology debuted in Google Glass, and then, in the same year, renamed HDR +, appeared in the Nexus 5.
How HDR+ works
What about dynamic range expansion? As we already know, using a fast shutter speed saves us from overexposed places. It remains only to remove the noise in the dark area using the previously described algorithm.
At the final stage, the resulting image is post-processed: the algorithm minimizes vignetting due to light hitting the matrix at an oblique angle, corrects chromatic aberration by replacing pixels at high-contrast edges with neighboring ones, increases green saturation, shifts blue and magenta hues towards cyan, enhances sharpness (sharping ) and performs a number of other steps to improve the quality of the photo.
On the left is a photo from a stock Samsung camera in HDR, and on the right is a photo created in Gcam in HDR +. It can be seen that the algorithm sacrificed the detail of the sky to draw objects on the ground.
