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BOOKS AND ARTICLES Using a digital camera as a camcorder
First, let's try to take a photo with a video camera, and then shoot a video with a camera. At the same time, we will evaluate not the quality of the filmed material (we will return to this a little later), but only whether it was convenient for you to shoot. Most will answer: "No, it is inconvenient to take pictures with a video camera, and it is inconvenient to shoot video with a camera." And it's not just unusual - many users masterfully own both of these devices for their "intended purpose", but they, most likely, were dissatisfied! The fact is that the requirements for the “grip” with which we hold the camera are completely different in each of these cases. The camera should be such that it is convenient to hold it in your hands, making manipulations with the camera on the composition of the frame and framing, mainly with the help of your wrists*, and at the same time be able to firmly fix the camera with both hands, squeezing it with your fingers at the time of shooting. True, while manipulating the Zoom and other controls, the camera may move slightly, but in this case it is practically unimportant - the main thing is that the camera should be rooted to the spot at the moment of shooting. * Note: of course, there are various wrist straps that fix handles and “butts” for cameras, but still they are designed for special conditions (for example, for working with long lenses), and under normal shooting conditions, as a rule, are not used. We hold the video camera with the whole palm, while the fingertips are free from holding it, we can even relax the palm - the camera will not go anywhere. The second hand only supports the camera, and the composition of the frame is manipulated not so much by a rather stiff wrist, but by the entire forearm. In this case, the movements are more limited relative to the "camera" grip, but here this is not perceived as a drawback - in the process of video shooting, too fast panning would be rather harmful, but when working with Zoom and other manipulations with the controls during the shooting process, the video camera is held more stable. There is also a kind of "pistol" grip, but it is somewhat compromise both for the camera (after all, it is too "harsh" for it) and for the video camera (all manipulations to control video shooting here have to be done only with the thumb - the only one free from it retention). In addition, it is more convenient to hold a camera with a "pistol" grip not at eye level, but somewhat lower, so usually such cameras do not have an optical viewfinder.*, and are equipped only with an LCD display. * Note: many old film camcorders with optical viewfinders also had a "pistol" grip, but there, due to the large size of the camera, the hand was at chest level. Now let's talk about the lens of the camera and video camera. A lens, and especially a Zoom lens, is a complex optical device. The greater the zoom ratio of the lens, and the greater the aperture ratio it has, the less, other things being equal, it will have sharpness. Of course, from a technical point of view, you can make a fairly sharp and fast lens with a large Zoom range, but it will turn out to be very heavy and extremely expensive. Therefore, a compromise needs to be found. Well, with any compromise, first of all they sacrifice a "minor" function ... Consider from this point of view the requirements for photo and video lenses. The camera's matrix has a high resolution, but if its lens is not sharp, then there will be no sense from the matrix - the picture will turn out to be "soapy", unsharp. Therefore, the aperture ratio and Zoom range of digital cameras are quite moderate. If we talk about cameras with fixed lenses (and now we are interested in them, as they have the ability to record video), then their aperture rarely exceeds 2.0-2.8, and the Zoom range, as a rule, is from three to five, and only for individual models reaches 10-12 - by "camera" standards, this is already an ultra-reason. In addition, if when photographing we do not have enough maximum focal length of the lens, and we do not have the opportunity to get closer, then in extreme cases we can take a picture of a more general plan than we would like to get, and then cut out the desired area in the photo editor. Of course, this is undesirable, but in this case it is still not fatal. We also note that when photographing in low light conditions, we have the opportunity to use a flash. The resolution in video shooting is much less than in photography, so such a high sharpness is not required from a video lens. This allows (at the expense of some reduction in sharpness) to make a video lens much faster, and with a larger Zoom range, than a photo lens. In addition, a "clean" camcorder usually has a smaller sensitive sensor. For example, the 1/2.5" CCD sensor installed in the cameras considered at the beginning of the article is simply "huge" by video camera standards. Smaller sensor sizes also make it easier to create a fast zoom lens at a moderate price. In video shooting, we are practically deprived of the opportunity to crop after shooting as when photographing, and we do not have the opportunity to use the flash during video shooting. Therefore, a tenx Zoom of a conventional video lens looks almost a record by camera standards, and a typical three to fivex Zoom of a photo lens by the standards of video cameras looks simply not serious. The same can be said about aperture ratio - if video lenses are characterized by values of 1.5-1.8 and even brighter, then, as we have already noted, in a photographic lens (especially ultrasonic) the aperture value rarely exceeds 2.0-2.8. Thus, in cameras, the lens has "excessive" sharpness for video shooting, but it is too dark for this, and its Zoom range is too small. True, there is also a digital Zoom :-) "What a digital Zoom! It's mauvais ton!!!" - for sure, both video and amateur photographers will say. And they will be right! Or rather, in this case, ALMOST right ... And here's why "almost": The fact is that the resolution of the CCD matrix of the camera is many times greater than required for video shooting, and even if only a part of the sensor area, this may be enough to provide the necessary resolution for video shooting. Of course, due to the decreasing useful area of the matrix, noise becomes more noticeable, but the clarity remains quite high. So such a digital zoom is better than nothing, and sometimes it can somehow compensate for the small range of the optical zoom of the camera when shooting video. Unfortunately, such a possibility of a large matrix is not always realized by manufacturers of photographic equipment; a simpler algorithm for working with a catastrophic drop in resolution is often used. In addition, digital Zoom is rarely studied in reviews and tests, so it is quite difficult to say in which camera models digital Zoom can be used for video shooting, and in which it is a useless "chip".
Let's continue talking about the matrix. As we have already noted when considering lenses, the CCD matrix used in cameras is simply huge compared to the one usually used in video cameras. In principle, this could well not only make it possible to compensate for the relatively low aperture ratio of a camera lens, but also achieve high sensitivity when shooting video. However, not everything is so simple here either. The fact is that the information received by the matrix must not only be recorded, but also read, delivered to the digital processor of the video camera, and then processed and stored. If you can spend a relatively "much" time on this when shooting a photo (several tenths of a second), then when shooting a video, you have to do it much faster - 30 times per second. If the task of processing and saving information during video shooting has already been successfully solved for both video and photo cameras (we will talk about this a little later), then reading information is still a "needle's eye" for multi-megapixel CCD matrices. In modern video cameras, the resolution of the matrix usually does not exceed two or three megapixels, which allows you to read information from it at the speed required for video shooting. In cameras, the CCD matrix has a much higher resolution, which seriously complicates the task. Creating a matrix capable of transmitting "to the outside world" such a large amount of information at the right speed is still too difficult a task. Therefore, when shooting video, not all pixels of the camera CCD matrix are often processed, but only a part of them. For example, to form one "video pixel", information from nine or even only four pixels is used, i.e. when shooting video in standard resolution, information is read only from one and a half to three megapixels of the CCD matrix. It is easy to calculate that in this case only from a quarter to a half of its effective area is actively working.*. Although the sensitivity is 4-9 times higher than in the photo mode, it turns out to be much less than a "clean" camcorder with a CCD matrix of the same size would have. * Note: we emphasize that we are talking about the use of pixels uniformly distributed over the entire effective surface of the CCD matrix, and not concentrated only in its central part. As a result, the advantages that could be given by the large size of the CCD matrix of the camera, due to the not very efficient use of its area when shooting video, are actually leveled, and in combination with the smaller aperture of the photo lens, the ability of the camera to shoot in low light conditions usually turns out to be somewhat worse than that of a good one. video cameras. Let's mention one more problem, which is a consequence of the high resolution of the camera and the large (by "video camera" standards) size of its CCD matrix. The fact is that the larger the size of the matrix, the smaller the depth of field (depth of field), and the more accurate the focus should be. Therefore, cameras require much more "small-step", and, as a result, more "thoughtful" focusing (of course, video cameras also come with a large matrix, but these are cameras of a completely different class, with a different, much more expensive focusing mechanism). When shooting still images, the extra few tenths of a second required for precise focusing is unpleasant, but not as deadly as when shooting video, when all this will be visible on the screen, especially if optical Zoom was used during the video shooting, or the focus point was changed. Therefore, when filming fast-moving scenes (for example, sports competitions), the camera is not always able to focus quickly enough, much less follow a fast-moving subject in tracking focus mode. The rest of the shortcomings associated with using the camera as a video camera are more local in nature, associated with specific models, but they should definitely be mentioned. To begin with, let's talk about the overall quality of the video, due to the method of its compression. It is for this that it is traditionally "customary to scold" the use of cameras for shooting video. A few years ago this was absolutely true. At that time, Flash memory cards were very expensive, their volume was small, and their speed was not high, so when using MJPEG compression, photo equipment manufacturers were forced to severely limit the bitrate when recording video. Often they limited not only the bitrate, but also the resolution or frame rate. MPEG encoding, in principle, made it possible to significantly increase the recording time, but the first cameras using such encoding, due to the very high resource intensity of such a process, did not cope with this task very well. Now the situation has changed significantly. Flash memory cards have fallen sharply in price, their volumes have increased many times over, and manufacturers of photographic equipment no longer need to restrain their appetites for voracious MJPEG encoding. So many modern cameras with this encoding provide a bit rate that is quite sufficient for high-quality video recording. The performance and "skill" of camera processors have increased many times, so that many of them "learned" not only to encode video in MPEG4 ASP much better (their video quality level here became comparable to the lower models of miniDV camcorders), but also mastered MPEG4 AVC (h. 264) encoding, including for high-definition video. So in this regard, many cameras with video recording in AVC, and even more so AVCHD, are no different from the corresponding AVCHD camcorders. However, video recording quality can vary greatly from model to model. It often happens that cameras that differ in only one character in the name have video capabilities that are simply incomparable in all important parameters. Therefore, this issue needs to be given increased attention when choosing a camera. It is advisable to find and view test videos to make sure that such video quality suits you (well, or does not suit you :-\ ). Unfortunately, only a few models of cameras in this class have an optical stabilizer, some at best are equipped only with an electronic stabilizer for video shooting, or even not at all. You also need to pay attention that, even with the presence of an optical stabilizer, some cameras use it only when taking pictures, and use digital for video. So when choosing a camera and this issue should also be given considerable attention. We note another feature that is often found in inexpensive cameras. The optical zoom drive is a mechanical device, the noise from which can later be heard on the video. Of course, this problem is peculiar not only to photo cameras, but also to video cameras. They try to deal with it using less noisy mechanisms, directional microphones and other tricks that significantly increase the cost of the camera. But some manufacturers of photographic equipment are trying to save on the "minor" function of the camera, and "fight noise" in other, less expensive methods. For example, in some cameras, optical zoom can only be used before video recording begins, and when video recording has already begun, the Zoom drive is blocked. So to say, "no Zoom - no problems" :-(. Sometimes the opportunity to use the optical Zoom is left, but during its operation they muffle the sound with the help of a low-pass filter, or even turn off sound recording altogether. "No sound - no problems " Consider another issue directly related to the use of a digital camera as a video camera. It's a matter of price. At first glance, the video features in this case are absolutely free. However, this actually only applies to cameras with primitive video features. More advanced photo and video cameras, as a rule, are more expensive than the simplest devices in this regard. An analysis of the prices of cameras with advanced video capabilities and simple cameras close to them in other functions shows that the "issue price" here is usually $50-$150 or even more, especially for cameras with high-resolution video recording. On the one hand, it seems to be not so much, but still not quite for nothing. But, on the other hand, such a camera will still be cheaper than the total cost of a separate photo and video camera (even if it is an entry-level one). Let's note a few more arguments in favor of using a digital camera as a video camera. If you are going to shoot both photos and videos, then you will need to take with you either one camera with advanced video capabilities, or both of these devices separately. It is obvious that one camera takes up much less space, and weighs less than a camera and a video camera. This can make a huge difference, for example, in extreme travel conditions, and even in a simple hike, lighter weight plays a big role. In addition, the 2-in-1 device gives you more operational space when shooting. For example, if during a “photo session” a scene suddenly appeared in the frame that would be more rational to shoot in motion, then the camera will allow you to switch from one mode to another with just one movement, which is simply impossible if you use a “separate” camera and video camera. But many everyday home scenes, in particular, shooting children or animals, can turn out to be unique ... Some cameras even allow you to take a picture without stopping video recording at all, or have special modes in which when you press the shutter button, a picture is first taken and video recording starts at the same time . Sometimes this can be quite convenient. When camping or traveling, a camera with advanced video capabilities can be useful even if you have a "separate" video camera. In this case, one of the operators is "armed" with a video camera and shoots video, and the second - with a camera, mainly taking pictures with it, but if necessary, having the opportunity to shoot a small video clip. Then the video from both cameras will be edited into a single film, some of the frames of which were taken from different points. However, here it is necessary to mention one more feature of "camera video". The fact is that almost all cameras with advanced standard-definition video recording capabilities "can" do this only with NTSC parameters - 480 lines at 30fps, while camcorders (if we talk about Europe and Russia in particular) are more likely to write with PAL parameters - 576 lines at 25fps. If only frames taken by the camera are used in the film, then this does not matter much - now, in fact, all DVD players and TVs can display NTSC video, so in this case this feature of the cameras is not a drawback. But if you plan to mount video from different cameras in the film, then you will need to reduce them to the same parameters. From a technical point of view, this is not a problem now, almost all video editors can easily do this, but the quality of the finished video may suffer. Perhaps the predominance of cameras with NTSC recording is due to the fact that almost all cameras use only frame-by-frame video recording. The question of which is better: frame-by-frame (progressive) vs interlaced (interlaced) video is very ambiguous, it requires separate consideration and is beyond the scope of this article. Let's just say that interlaced video looks smoother on interlaced display devices (many CRTs, part of PDPs), but on progressive scan devices (LCDs, most PDPs), viewing such video can be accompanied by a "comb effect" or other negative phenomena. At the same time, progressive video is better suited for viewing on such devices, but looks less smooth than interlaced. However, in this case, a slightly higher fps with NTSC recording allows you to compensate for this to some extent. As there are more and more progressive scan display devices, this feature of "still camera" video is not in itself a disadvantage, and in some cases can be regarded rather as an advantage. But still, it is not very pleasant that in this parameter we are actually deprived of the possibility of choice. In conclusion, we note that only cameras with a small CCD matrix by "camera" standards have sufficiently high video capabilities - as a rule it is 1/2.5", well, at best 1/1.8". Thus, if you want to have a camera with a larger matrix, or even more so a SLR camera, then you will definitely have to purchase a separate camera for video shooting. So, let's try to draw some conclusions from the above, formulate the arguments "for" and "against" the use of a digital camera as a video camera. But, since some of the advantages are a consequence of the shortcomings, it will be more convenient to consider them in reverse order, first give the arguments "against" (contra), and then "for" (pro): cons:
Pro:
Conclusion. Let's formulate some conclusions: If you do not accept compromises in both video and photography, you are ready to carry a multi-kilogram case with a "SLR", video camera and accessories for them, so that as a result you will be able to take great pictures and video frames in any shooting conditions, and at the same time you are ready pay a fairly large amount for a high-end camcorder, then choose it. If "DSLR" is not your choice, you are going to settle for a camera with a small CCD matrix, and also get an inexpensive video camera, then you should probably look at a camera with advanced video capabilities. A similar choice can be recommended for conditions where the weight of the camera is extremely important (for example, extreme or hiking), or the speed of the transition between video and photography (for example, everyday home video shooting, including shooting children). Publication: ixbt.com
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