To store pictures in the camera, storage devices are indispensable. And no matter what they say about the fact that in recent years memory has fallen several times in price, it is still quite expensive. No one complains about the "extra" memory, everyone only talks about its lack. Manufacturers usually do not spoil us with the amount of memory built into the camera, and memory has to be bought in ninety-nine cases out of a hundred. After all, only eight to twelve pictures in JPEG format can fit on a standard eight-megabyte card, and even less in an almost incompressible TIFF format. Agree that it is extremely inconvenient to transfer to a computer or keychain with flash memory every six or ten shots.
Most cameras now have a removable flash memory that stores information without consuming power and, in addition, allows you to connect a portable mass storage device. If the removable memory card is completely filled with images, then you can simply remove it from the camera and insert another module in its place or continue shooting with the built-in memory. A removable memory card is placed in a special compartment of a digital camera, or, more correctly, in a slot. Each type of media has its own slot design - you cannot insert a memory card that the camera does not support into it.
Most slots are designed to prevent the card from being installed incorrectly (eg upside down). The cameras of most models usually “see” only one of the two available memory cards at a time. If a removable card is inserted into the slot, the camera "forgets" about the existence of the built-in memory. If there is no free space left on the removable card, but you want to shoot more and more, you should remove the card from the slot - then the camera will see the free built-in memory. Comparing the advantages of digital cameras, experts pay attention to the type of memory used. It is always useful to know how compatible the camera's memory is with other devices and whether the cheapness of the "brains" will turn out to be expensive or even a hindrance in operation. We list the information storage devices known today, used in digital cameras.
For laptop owners, PC Card ATA, or, as it is also called by the name of the slot, PCMCIA is best suited. Such a connector in laptops, as a rule, is available. Such a card is used to store large amounts of data (up to 1 GB) and is used as an external medium, depending on the type, in photo and video cameras and in laptops. These cards are similar in size and shape to a thick business card. PCMCIA cards are commonly used in large cameras that are close to professional in performance.
Occasionally in digital cameras Mini Card devices are used. They are not very reliable. In addition, their data reading speed is quite low. But they consume little energy and have small dimensions: 38x33x3.5 mm. Mini Card devices hold 64 MB of data.
The most common memory format today, Compact Flash, is similar in many ways to PC Cards, but its physical dimensions are much smaller. More recently, the development of technology has made it possible to increase its maximum volume to 1 GB. Compact Flash media has no moving parts and consumes relatively low power - from 3.3 to 5 V, which has made these cards super popular with manufacturers of digital photographic equipment. Compact Flash cards are strong and durable. Manufacturers claim that they can store information for at least a hundred years.
Compact and not too expensive, Smart Media Cards - or, as they were called more recently, SSFDC (English short for Solid State Floppy Disk) - have been around since 1997. They are less compatible with digital devices than Compact Flash cards, and here's why. Smart Media Cards do not have a controller found in Compact Flash and other storage devices. So they sort of rely on a controller built into the camera. Smart Media Cards are up to 128 MB and 45x37x0.76 mm - approx. Matchbox. In addition to reduced compatibility, they also have other disadvantages: fragility (the life of the carrier is no more than five years), fragility, exposure to external influences and small volume. The latter once seemed sufficient, but today it is quite small compared to that provided by other carriers. To transfer images to a computer from Smart Media cards, a dedicated Smart Media Adapter is required.
Tiny, postage stamp-sized MultiMedia Card (up to 128 MB) is one of the smallest small capacity storage devices. Initially, they were conceived for portable telephones, but their small size and weight, as well as a simple interface and reduced power consumption, attracted the attention of manufacturers of various digital devices. MultiMedia Cards are increasingly being used in "hybrid" devices such as a digital camera with a built-in MP3 player, and also (sometimes) in mobile phones with support for multimedia messages. It must be said that the race of manufacturers of RAM for miniaturization led to the emergence of a MultiMedia Card variant called RS-MMC (Reduced Size MultiMedia Card, reduced size multimedia card). The size of RS-MMC has been reduced to 32x24x1.4 mm and is now widely used in smartphones and new generation mobile phones.
Memory Stick from Sony with a maximum capacity of 128 MB looks like a stick of chewing gum and weighs only 4 g, but has not yet found wide application - although the devices for connecting it can be very exotic. Still: closed standard, high price and small volume. Cameras that provide for the use of this type of memory are produced only by Sony Corporation (they are not compatible with other types of memory).
But SD Cards (Secure Digital Cards), which have only recently begun production, seem to be poised to become very popular media. Today they contain only 256 MB of data, which is quite a bit, but the interest in such cards is not at all accidental. The fact is that SD cards are equipped with cryptoprotection against unauthorized copying and protection against accidental erasure and destruction. Such properties have aroused keen interest from both media corporations and consumers, who sometimes wish that pictures from their personal lives could not be copied without their knowledge. SD cards are very small - with dimensions of 24x32x2.1 mm they weigh only 2 g. The SD Card slot also accepts a MultiMedia Card, which makes the "secure" format even more promising. It is also important that SD Cards consume very little energy and are quite durable.
There were even disposable (non-erasable) flash cards from the Shoot & Store series from SanDisk. Their manufacturer believes that the appearance of such media will contribute to a truly massive transition from film to digital. Indeed, with the advent of disposable memory, the problem of storing images will be solved and the need for a computer will disappear by itself. In terms of cost, disposable flash cards will be comparable to conventional film, and the difference in price is compensated by their reliability and the convenience of choosing frames for printing.
The recently introduced mini DataPlay data offload disks are quickly gaining popularity because of their low cost: 500 MB of such memory costs only $ 10. DataPlay uses smaller DVD optics and the drive looks like a hard drive. In practice, DataPlay can be called a miniature DVD (33.53x39.5 mm in size). DataPlay has announced plans to release devices with a capacity of 4 GB. Here's just one thing is not good: the DataPlay disc is disposable and does not provide for the possibility of re-recording. But how cheap!
In digital cameras, even media such as CD-R discs and CD-RWs. Yes, don't be surprised! The CD is inserted into the camera and carries up to 156 MB of recorded data! True, Sony, which produces such exotics with direct recording of images on CD, is still alone on the market: no one else is trying to imitate it.
Now knowing the pros and cons various kinds memory, try to evaluate the memory of your camera (or the one you are about to buy) against the backdrop of all this variety of external storage media.
conclusions
When removing the card from the camera for the first time, pay attention to how it is inserted. Reversing the direction of the pins can damage both the card and the camera.
Protect the card from the accumulation of static charges. If you had to remove it from the camera, place it on a metal surface or foil from time to time. Avoid rubbing the card against the fabric.
Be especially careful with the contacts of the card. Avoid scratching or other damage.
Keep in mind that many cards are quite fragile. If you drop the card, you can lose both the data stored on it and the money you spent on it.
Any sufficiently complex electronic device is a computer in one form or another, since it provides either information processing or some kind of reaction in response to its change. In particular, any film camera that provides automatic calculation of exposure and focusing is equipped with the simplest or most complex (depending on the class) microprocessor - and often more than one. These devices, analyzing information from sensors, focus the lens and calculate the aperture and shutter speed - and a specialized database is used for the latter operation.
And even more so, you can’t do without a computer for a digital camera that stores the pictures themselves in the form of binary information. Moreover, even the set of components of such a camera is quite familiar to any user familiar with the stuffing of a computer. Among the nodes of a digital camera, you can find ROM, RAM, modest power consumption CMOS memory, non-volatile flash memory, hard disk drives (HDD), often called "hard drives", and even such exotic things as floppy drives and CD-drives. RW.
Obviously, most readers are familiar with the purpose of the above devices - all of them, one way or another, serve for operational or long-term data storage. However, the question may arise how these components are used in digital photographic equipment - especially considering the fact that some of them are distinguished by both excellent "gluttony" (in terms of electricity) and impressive dimensions.
In order for the story to go from simple to complex, it is advisable to review chronologically - both regarding the development of the cameras themselves, and regarding the processes taking place in a digital camera.
ROM, RAM and CMOS
So, if we recall the very first amateur digital camera, which appeared in 1990 and was called the Dycam Model 1 (although it was better known under the name Logitech FotoMan FM-1), then its internal organization will resemble the most primitive computers of the time. The ROM contains both a set of programs that control the "photographic" part of the programs (that is, exposure calculation algorithms), and utilities that provide image formation based on data coming from the ADC, as well as subsequent information compression.
All programs stored in ROM are loaded into RAM after the camera is turned on. Pictures are also stored here - the Dycam Model 1 did not have non-volatile information storage facilities, and when a pair of "finger-type" batteries, which were the main power source of the camera, were discharged, all the captured frames disappeared. Of course, this state of affairs categorically could not suit users, so the following models of digital photographic equipment already had devices that made it possible to store images indefinitely (or almost indefinitely) for a long time without any energy sources. However, both ROM and RAM were preserved in these cameras - the first type of memory still stored programs, but the functions of the second expanded somewhat.
The fact is that digital cameras have found color. However, this color for each frame had to be restored - interpolated, and for such operations it is necessary to RAM, so the pictures still ended up in RAM, only this time not for storage, but for processing. This processing consisted of forming a snapshot based on ADC data, color restoration, and information compression. The resulting images were stored in the built-in non-volatile flash memory of the camera.
In RAM, not only image processing was performed. A section of this memory was allocated and assigned to the role of service memory - it stored all the camera settings made by the user. The first models of digital cameras were quite simple, so the resolution, compression ratio and flash mode selected by the user were lost when the camera was turned off - it was not difficult to set these parameters the next time it was turned on. But when the exposure compensation and white balance functions appeared, it was decided to save the settings made by the user in the RAM section allocated for service memory - at least until the next battery change. As the resolution of CCD matrices grew, it became obvious that storing pictures in the built-in flash memory would obviously limit the user in terms of the available number of frames. Therefore, cameras have acquired interchangeable flash memory modules, from which not only users, but also manufacturers have benefited. Firstly, the demand for cameras increased (it became possible to take them on vacation), secondly, a market for memory modules arose, and thirdly, various devices became widespread that allow reading data from a module without using a camera. These devices, called readers, had a wide variety of designs (they will be discussed in more detail below), although they had one feature in common - they provided access to images organized as files.
Accordingly, another load fell on the camera's RAM - it converted the image into one or another file format. The most common are JPEG, TIFF and RAW files. It should also be noted that by the time of the appearance of removable media, some manufacturers began to equip their cameras with the functions of increasing / decreasing the brightness, contrast and clarity of the image, as well as converting the image to black and white. All these transformations were carried out after color restoration and, frankly, much better results could be achieved using specialized image processing software.
Most often, frames are saved in JPEG files. This abbreviation hides the name of the organization (Joint Photographic Experts Group), which has developed a fairly effective information compression algorithm. This algorithm consists of the following steps:
- converting the image's color space from RGB (which uses shades of red, blue, and green to display all colors) to YUV (where Y is the brightness of the pixel, and U and V are the color data). In this case, first of all, the safety of information about the brightness of the pixel is ensured, and for human vision this is more important than color data.
- splitting the frame into blocks of 8X8 pixels, followed by a discrete cosine transformation of these blocks, which translates the image into a set of harmonic oscillations with different amplitudes and frequencies.
- analysis of amplitude-frequency characteristics for the repeatability of color fields, followed by the exclusion of 50 percent of the brightness and 75 percent of the color data.
It is because of the last step that JPEG is classified as a lossy compression algorithm. In other words, even with the minimum compression ratio, it is impossible to completely restore the original image. And at maximum compression ratios, too much of both brightness and color information is lost, and JPEG artifacts are more and more clearly visible in the image - "blurred" borders of contrast areas, splitting the frame into blocks of 8X8 pixels, and so on.
Unlike the JPEG algorithm, the compression used in the TIFF format does not result in data loss. The algorithms used in this case are very similar to those used in archiving programs and provide 100% image recovery. However, TIFF files take up noticeably more space, even compared to JPEG files with minimal compression, while errors in exposure calculation or focusing spoil the frame much more than JPEG artifacts. The conclusion follows from this - you should shoot as many frames as possible and select the most worthy ones, and from this point of view, the JPEG format is preferable.
RAW format files are "casts" from the CCD without any transformations - first of all, color interpolation is not performed. At the same time, uncompressed files take up more space than TIFF files, and their processing on a computer requires specialized and functionally limited software. However, at the moment, most manufacturers provide compression of RAW files, and they often turn out to be more compact than TIFF files. And for greater convenience in further image processing, plug-ins for Adobe Photoshop are released that allow you to use the full power of this package when processing RAW images.
The question arises - "why do you need a RAW format at all?" The fact is that sometimes both the dynamic range of the matrix and its ADC make it possible to obtain an image with a greater color depth than the standard 24 bits used in JPEG and TIFF formats. And just for saving a 30, 36 or 48-bit RAW image is best suited - excess bits can always be used to correct "overexposure" or "underexposure".
Along with the resolution of CCD matrices, their performance also steadily increased. In the end, the speed of reading data from the sensor became such that it became possible to implement the continuous shooting mode, in which the camera takes a series of shots with minimal intervals between them. And since at high resolution even a short series requires a fairly impressive amount of memory, the size of the RAM has grown significantly. Since then, this type of memory has become known as buffer memory. Simultaneously with the continuous shooting mode, the models began to be equipped with the functions of exposure bracketing, exposure lock, multi-zone autofocus and other useful things. At the same time, as the resolution grew, power consumption also increased, so the batteries had to be changed especially often. And every time I had to completely adjust the camera. This state of affairs did not suit the users, as a result, it was decided to use a CMOS memory with a very modest power consumption as a service memory - it actually "was enough for one" tablet "(meaning a watch battery). Experienced readers guessed that the solution was borrowed from the world of personal computers, in which the motherboard settings are also stored in a CMOS memory powered by a "pill".
However, what is good for a computer is not always good for a digital camera. The compartment for the "tablet" took up space in the case, it was necessary to bring a hatch to one of the panels to replace the battery, and the design of the camera as a whole became more complicated. Therefore, a different solution was required, which, in the end, was found.
Flash memory
As already mentioned, the main distinguishing feature of flash memory is its non-volatility - it is able to store information for a very long time without any energy sources. This is similar to ROM, but unlike the latter, flash memory allows modification of the data stored in it. This is achieved by the fact that when reading information, a low voltage is used, and when writing, a high voltage is used.
The combination of these properties has led to the fact that in digital cameras, flash memory has become the main device for long-term storage of images. In early cameras, flash memory was built-in and after it was full, images were uploaded to a personal computer. With increasing file sizes, replaceable memory modules have become widespread, but the built-in flash memory in cameras has also been preserved.
As already mentioned, the use of CMOS tablets as a service memory complicates the design and increases the dimensions. Therefore, it was decided to use the built-in flash memory of the camera as a service one - in this case, the issue of power supply automatically disappeared. Moreover, there was an opportunity to solve two more newly emerging problems.
Firstly, due to the quite understandable "hurriedness" of manufacturers (after all, the market must be conquered), it often turned out that some of the functions did not work quite the way they should. The same problem occurs with computer motherboards and it is "treated" by flashing basic system input / output (BIOS), which for the time being is not stored in ROM, but in flash memory. This solution has migrated to digital cameras, and now to correct "inadequate behavior" when calculating exposure or focusing, it is enough to get the latest software "patch" and "impose" it on the built-in software camera stored in flash memory.
Secondly, the increase in the resolution of the matrices had a negative impact on the production volumes - an increasing percentage went into marriage due to the abundance of "sticky" pixels. At the same time, the demand for digital photography continued to grow. Therefore, the rejection standards were made more liberal, and so that users would not be embarrassed by "sticky" pixels, cameras began to be equipped with a mode that scans defective elements of the CCD matrix and stores their coordinates in the service flash memory. And when generating a full-color image, the elements included in the "list of stuck pixels" were excluded from consideration.
Removable Flash Memory Modules
So, by the time the resolution of CCDs approached the megapixel mark, most manufacturers of amateur digital cameras switched to replaceable flash memory modules. However, it should be noted that the initiative to switch to removable storage media belonged to the developers of digital SLRs.
It was in the 1994 Kodak DCS-420 SLR digital cameras that slots for installing PCMCIA cards first appeared. In turn, these flash memory cards were developed even earlier for portable computers by the Personal Computer Memory Card International Association (PCMCIA). The standard recommended by this organization described both the shape and voltage of the connectors and the dimensions of the cards. It was also planned that modems, network cards, SCSI adapters and other devices would be produced in this form factor and using the same connector. The standard was later renamed PC Card.
PCMCIA card
Ultimately, three types of PCMCIA cards emerged. All of them have equal length and width (85.6X54 mm), but their thickness is different: type I is 3.3 mm thick, type II is 5 mm, and type III- 10.5 mm. The cards also differ in supply voltage - 3.3 or 5 volts. Flash memory cards were mainly Types I and II.
Despite the fact that the dimensions of the PCMCIA-slots were more suitable for impressive-sized "DSLRs", a place for them was also found in the cases of some amateur cameras - for example, the Kodak DC-50. However, the CompactFlash standard, which appeared in 1994, which became the development of PCMCIA, achieved much more success.
The appearance of cards of this type became possible due to the increase in the recording density in flash memory chips. As a result, chip sizes were reduced, and SanDisk decided to create a new type of memory card, while maintaining compatibility with the PCMCIA format - although the number of contacts was reduced from 68 to 50, the CompactFlash modules were electrically fully compatible with their predecessors. And for mechanical compliance, a CompactFlash-PCMCIA adapter in the form of a PCMCIA card was enough, into which, due to its small size (43X36X3 mm), new modules were inserted. Well, the entire assembly could be placed in a laptop slot and read images directly into a computer, without using any connecting wires or software to communicate with the camera.
CompactFlash module
Like PCMCIA cards, CompactFlash modules initially differed in supply voltage - 3.3 and 5 volts. Then another difference was added - CompactFlash type II cards appeared, the thickness of which was already 5 mm. Thanks to this, it became possible to significantly increase the capacity of the modules, while once again the perspicacity of the developers of the standard deserved praise.
The fact is that the memory controller was located directly in the CompactFlash module, in much the same way as in hard drives. Thereby newest maps high capacity could be installed in a relatively old camera. This flexibility has given the CompactFlash standard unrivaled longevity.
However, placing the controller on the map has its downsides. First, this increases the cost of the device. Secondly, as a result, manufacturers get "hands untied" and they label cards indicating "unformatted capacity" (for example, "64 MB"), although in reality 60 to 63 MB remain free for data storage.
After the spread of the USB interface, CompactFlash-USB data readers became popular. Moreover, CompactFlash modules appeared, which had a chipset that implemented the USB interface. These modules were equipped with a cable that had two connectors - one was intended for connecting to a computer's USB port, and the second, 50-pin, allowed you to connect a CompactFlash card directly to the cable and read data from it into a computer without any additional devices.
Perhaps, in the field of minicomputers, CompactFlash modules have become as widespread as in digital photographic equipment. Moreover, the reserves built into the interface (actually inherited from PCMCIA) made it possible to implement not only memory modules, but also modems and network cards within this format.
In general, the CompactFlash standard for the most part satisfies all modern requirements and is notable for its high popularity, good exchange rate and large reserves for increasing memory volumes.
Question long-term storage digital photography is somewhat deeper than it might seem at first glance. Unlike "real-time" files, a digital photo archive must be guaranteed to remain intact for years and decades. It would seem, what is easier? There are many different media available: optical CDs, DVDs and BlueRay (BR) discs, all kinds of flash drives and memory cards, conventional hard drives and even remote file storages, the so-called file hosting. The main problem of long-term storage of digital images is the reliability of media, and capacity, speed or ease of use fade into the background. It will not be superfluous to remember that when choosing a storage medium, you should take into account the frequency of file accesses. It is one thing to have an optical disc locked in a safe “for ages”, and quite another to have a family album constantly updated. As usual, winning in one, we lose in another, the law fully applies to information carriers. Unfortunately, the ideal storage has not yet been invented. We will try to understand today's abundance and help to make conscious choice without relying on advertising.
Volume. In fact, the more the better, the stock doesn't hurt. But if the budget is limited, the required storage capacity can be estimated based on the total number and size of photos. The author only accepts archives in uncompressed formats, such as TIFF. In a common JPEG, the size of a photo is about 5 times smaller. It is very simple to count, we divide the capacity of the carrier by the volume of the photo. The first one is written on the device itself, and the approximate size of the scanned photo can be estimated from the plate (the dimensions are maximum for color depth when scanning 24 bits):
| Resolution, DPI | Size, cm | Approximate volume, Mb |
| 300 | 9x12 | 5 |
| 300 | 10x15 | 8 |
| 300 | 12x18 | 11 |
| 300 | 20x25 | 25 |
| 600 | 9x12 | 19 |
| 600 | 10x15 | 30 |
| 600 | 12x18 | 42 |
| 600 | 20x25 | 110 |
| 1200 | 9x12 | 72 |
| 1200 | 10x15 | 115 |
| 1200 | 12x18 | 170 |
| 1200 | 20x25 | 430 |
Media. The most compact and probably already the most common storage medium is the so-called flash (flash) memory. Tiny microcircuits are in memory cards, "flash drives" and mounted in various equipment. This type of memory is good for non-volatility, relative cheapness and capacity - today you will not surprise anyone with a 256 GB USB flash drive. The disadvantages include low exchange rate and, most importantly, not very high reliability. Manufacturers of memory chips claim a guaranteed data storage period of up to 10 years, but with a small caveat - under normal conditions. In this context, “normal” means “perfect”, which no one can surely provide. a common person. Stable temperature, humidity and even atmospheric pressure. The absence of radiation, both radio frequency and radioactive. No memory accesses during the retention period. These are “normal” conditions from the point of view of manufacturers ... Under normal use, individual bits of information can be lost already in the first months, after a couple of years, 20 percent (on average) of the recorded data will be distorted or inaccessible. Conclusion: flash memory is great for online data storage and with reservations for long-term storage. There is one caveat, but an essential one: it is required to rewrite all data to a new medium at least once a year. But it is cheap and compact, suitable for a constantly updated archive that is not designed for many years. It is better to buy memory from famous brands such as Kingston, Transcend, Sandisk and others that give a guarantee of at least three years.
Optical discs have been widely used for more than a decade and have undergone only three key stages of evolution - CD, DVD and BlueRay technologies. In appearance, only a specialist can distinguish disks of different generations, but in terms of capacity they differ by orders of magnitude. Compare: CD - 750 MB, DVD - up to 8 GB, Blu-Ray - up to 50 GB today and up to 200 GB are promised in the near future. For clarity, the first will fit approximately 20 big photos, on the second - about 200, and accordingly on the third - in the region of 1500 shots. It should be noted that BlueRay media is quite expensive in itself, and only very wealthy people can afford recording equipment. CDs are already a thing of the past, and today's leader in this area - DVD - is available to everyone. Therefore, BR discs as a home archive storage cannot yet be called mass-produced. About reliability. Here the bar is set by the material itself - a transparent plastic disc. It is obvious that plastic is afraid of high temperature (disc deformation) and mechanical influences (the surface is scratched). Both make it difficult to read the information correctly. But the number of read cycles is almost infinite, besides optical media indifferent to any type of radiation. From this we can conclude that DVDs, and in the near future BR discs, are well suited for long-term storage of photo archives, you just need to take care of reliable packaging. That is, the archive turns out to be compact and very reliable, but it is not convenient for replenishment and / or rewriting - the recording time of one DVD disc can reach up to an hour. The most reliable discs are from Verbatim or TDK, provided they are genuine. It is best to look for media with the words "ExtraLife", "Life Plus" in the name, and the like, which speak of increased storage reliability.
Hard drives- "hard drives" - have long and firmly settled in the niche of operational information storage. Modern technology allows you to create media with a capacity of up to tens of Terabytes (!), where you can record any conceivable photo archive. Hard drives provide high data transfer speed, a huge number of rewriting cycles at a low price and acceptable reliability. But it should be remembered that the hard drive is a complex and precise mechanical device, even if it is high-tech. Therefore, the reliability of storage is determined both by the operating conditions and the quality of a particular instance. Since magnetic recording is used, hard drives are "afraid" of strong magnetic fields and mechanical overloads, especially during operation. Restoring a failed media can be very expensive or beyond the capabilities of the wizard. But in more or less comfortable conditions, a hard drive is almost ideal for storing a photo archive, even a constantly updated one. Moreover, there are simple ways to increase the reliability of storage by an order of magnitude - the use of several hard drives simultaneously in the so-called RAID array. The array can be set up on most home computers, or you can purchase a specialized device (usually in the range of $300). The principle is simple: the storage is created from several identical hard drives, a special controller duplicates and controls the integrity of the recorded data, constantly monitors the status of each media. If one or even two disks fail (which happens extremely rarely), the information will not be lost and will be restored when new clean hard drives are connected. Thus, the reliability of storage increases many times, because even one hard drive is very reliable and can work for many years without turning off. The disadvantages of such a solution include bulkiness, high price, plus the need for some knowledge in computer hardware and software settings. These shortcomings are more than offset by the speed and reliability of the archive in an average home environment. WesternDigital (WD), Samsung, Hitachi hard drives perform well, it is advisable to look for a model for increased loads - it will be more expensive, but more reliable.
Remote data stores. With the development of the Internet, numerous file hosting sites have appeared - sites where you can upload your documents (whether photos, videos or just files) within the allotted quotas and at any time access files through any computer connected to global network. Usually, a very modest amount is provided free of charge, which can be expanded for the same modest money. Services vying with each other boast about the reliability and security of data - and many of them are not unfounded. Large companies can afford state-of-the-art and super-reliable file storage under the supervision of experienced professionals. System administrators do everything to prevent hacking of personal drives. And yet, who can guarantee that this company will still exist ten years from now? Who guarantees that there will not be a hacker who, out of hooligan motives, will put your personal files on public display? Yes, and there is access to the network today - not tomorrow. Still, remote storages are very convenient, especially when combined with a fast Internet connection, and are great for accumulating, updating and creating an archive, which in turn will be stored on a more suitable medium. I deliberately do not give links, because I do not have information about the reliability of a particular service. I myself use the foreign "DropBox" - it seemed convenient, and the service is no longer new.
And finally, the general very important rule , which is valid regardless of the type of media chosen: MAKE BACKUP COPIES! That's right, in capital letters! Let laziness, no time or expensive - at the first opportunity, make copies on different media. Personally, the author has the main archive, which "for centuries" - lies on two dozen DVDs, each disc in two copies. The online archive is on a RAID array of a home computer, and the most valuable files are duplicated on a remote storage on the Internet. Instead of an array, you can use a couple of large flash drives or external hard drives, but be sure to make copies of everything, don't be lazy. Remember that recovering a damaged storage medium is difficult, expensive and not always possible.
If anyone has not read the article, I strongly recommend that you read it, because the topic of today's article will overlap with the previous one. For everyone else, I will repeat the summary again. There are three types of cameras: compact, mirrorless and SLR. Compact ones are the simplest, and mirror ones are the most advanced. The practical conclusion of the article was that for more or less serious photography, you should opt for mirrorless and DSLRs.
Today we will talk about the device of the camera. As in any business, you need to understand the principle of operation of your tool for confident management. It is not necessary to know the device thoroughly, but it is necessary to understand the main components and the principle of operation. This will allow you to look at the camera from the other side - not as a black box with an input signal in the form of light and an output in the form of a finished image, but as a device in which you understand and understand where the light goes further and how the final result is obtained. Compact cameras We will not touch on, but let's talk about mirrored and mirrorless devices.
SLR camera device
Globally, the camera consists of two parts: the camera (it is also called the body - carcass) and the lens. The carcass looks like this:
Carcass - front view
Carcass - top view
And this is what the camera looks like complete with lens:
Now let's look at the schematic image of the camera. The diagram will show the structure of the camera “in section” from the same angle as in the last image. In the diagram, the numbers indicate the main nodes, which we will consider.
After setting all the parameters, framing and focusing, the photographer presses the shutter button. At the same time, the mirror rises and the stream of light falls on the main element of the camera - the matrix.
As you can see, the mirror rises and shutter 1 opens. The shutter in DSLRs is mechanical and determines the time during which light will enter the matrix 2. This time is called shutter speed. It is also called the matrix exposure time. The main characteristics of the shutter: shutter lag and shutter speed. Shutter lag determines how quickly the shutter curtains open after you press the shutter button - the smaller the lag, the more likely it is that the car that you are trying to shoot passing by you will be in focus, not blurred and framed as you did when viewfinder assistance. DSLRs and mirrorless cameras have a short shutter lag and are measured in ms (milliseconds). The shutter speed determines the minimum time that the shutter will be open - i.e. minimum exposure. On budget and mid-range cameras, the minimum shutter speed is 1/4000 s, on expensive (mostly full-frame) cameras it is 1/8000 s. When the mirror is raised, the light does not enter either the focusing system or the pentaprism through the focusing screen, but directly onto the matrix through the open shutter. When you take a picture reflex camera and at the same time look into the viewfinder all the time, then after pressing the shutter button you will temporarily see black spot, not an image. This time is determined by the exposure. If you set the shutter speed to 5 s, for example, then after pressing the shutter button you will observe a black spot for 5 seconds. After the end of the exposure of the matrix, the mirror returns to its original position and the light again enters the viewfinder. IT IS IMPORTANT! As you can see, there are two main elements that regulate the amount of light that hits the sensor. These are aperture 2 (see the previous diagram), which determines the amount of light transmitted, and the shutter, which controls the shutter speed - the time for which the light enters the matrix. These concepts are at the heart of photography. Their variations achieve different effects and it is important to understand their physical meaning.
The matrix of the camera 2 is a microcircuit with photosensitive elements (photodiodes) that react to light. There is a light filter in front of the matrix, which is responsible for obtaining a color image. Two important characteristics of the matrix can be considered its size and signal-to-noise ratio. The higher both, the better. We will talk more about photomatrices in a separate article, because. this is a very broad topic.
From the matrix, the image is sent to the ADC (analogue-to-digital converter), from there to the processor, processed (or not processed if shooting in RAW) and stored on a memory card.
Another important detail of DSLRs is the aperture repeater. The fact is that focusing is performed at a fully open aperture (as far as possible, determined by the design of the lens). By setting a closed aperture in the settings, the photographer does not see changes in the viewfinder. In particular, the IPIG remains constant. To see what the output frame will be, you can press the button, the aperture will close to the set value and you will see the changes before pressing the shutter button. The aperture repeater is installed on most DSLRs, but few people use it: beginners often don’t know about it or don’t understand the purpose, and experienced photographers roughly know what the depth of field will be in certain conditions and it’s easier for them to take a test shot and, if necessary, change the settings .
Mirrorless camera device
Let's immediately look at the diagram and discuss in detail.
Mirrorless cameras are much simpler than DSLRs and are essentially a simplified version of them. They do not have a mirror and a complex phase focusing system, and a different type of viewfinder is also installed.
The light flux enters the matrix 1 through the lens. Naturally, the light passes through the diaphragm in the lens. It is not marked on the diagram, but I think, by analogy with DSLRs, you guessed where it is located, because the lenses of DSLRs and mirrorless cameras practically do not differ in design (except perhaps in size, mount and number of lenses). Moreover, most lenses from DSLRs can be installed on mirrorless cameras through adapters. There is no shutter in mirrorless cameras (more precisely, it is electronic), so the shutter speed is regulated by the time during which the matrix is on (receiving photons). As for the size of the matrix, it corresponds to the Micro 4/3 or APS-C format. The second is used more often and fully corresponds to the matrices built into DSLRs from the budget to the advanced amateur segment. Now full-frame mirrorless cameras have begun to appear. I think in the future the number of FF (Full Frame - full-frame) mirrorless will increase.
In the diagram, the number 2 denotes the processor that receives the information received by the matrix.
Under the number 3 is a screen on which the image is displayed in real time (Live View mode). Unlike DSLRs in mirrorless cameras, this is not difficult to do, because the light flux is not blocked by the mirror, but freely enters the matrix.
In general, everything looks just fine - complex structural mechanical elements (mirror, focus sensors, focusing screen, pentaprism, shutter) have been removed. This greatly facilitated and reduced the cost of production, reduced the size and weight of the apparatus, but also created a host of other problems. I hope you remember them from the section on mirrorless in the article about. If not, then now we will discuss them, along the way, analyzing how technical features these shortcomings are due.
The first major problem is the viewfinder. Since the light falls directly on the matrix and is not reflected anywhere, we cannot see the image directly. We see only what gets on the matrix, then in an incomprehensible way it is converted in the processor and displayed on an incomprehensible screen. Those. There are many errors in the system. Moreover, each element has its own delays and we do not see the image immediately, which is unpleasant when shooting dynamic scenes (due to the constantly improving characteristics of processors, viewfinder screens and matrices, this is not so critical, but it still happens). The image is displayed on the electronic viewfinder, which has a high resolution, but which still does not compare with the resolution of the eye. Electronic viewfinders tend to go blind in bright light due to limited brightness and contrast. But it is more than likely that in the future this problem will be overcome and a clean image passed through a series of mirrors will sink into oblivion as well as “correct film photography”.
The second problem arose due to the lack of phase autofocus sensors. Instead, a contrast method is used, which determines by the contour what should be in focus and what should not. In this case, the lenses of the objective move a certain distance, the contrast of the scene is determined, the lenses move again and the contrast is determined again. And so on until the maximum contrast is reached and the camera focuses. It takes too much time and such a system is less accurate than the phase system. But at the same time, contrast autofocus is a software feature and does not take up extra space. Now they have already learned how to integrate phase sensors into mirrorless matrices, having received a hybrid autofocus. In terms of speed, it is comparable to the autofocus system of DSLRs, but so far it is installed only in selected expensive models. I think this problem will also be solved in the future.
The third problem is low autonomy due to the stuffing with electronics that are constantly working. If the photographer works with the camera, then all this time the light enters the matrix, is constantly processed by the processor and displayed on the screen or electronic viewfinder with high speed updates - the photographer must see what is happening in real time, and not in the recording. By the way, the latter (I'm talking about the viewfinder) also consumes energy, and not a little, because. its resolution is high and the brightness and contrast should be on par. I note that with an increase in the pixel density, i.e. reducing their size with the same power consumption inevitably reduces brightness and contrast. Therefore, high-quality high-resolution screens consume a lot of energy. Compared to DSLRs, the number of frames that can be taken on a single battery charge is several times less. So far, this problem is critical, because it will not be possible to significantly reduce power consumption, and one cannot count on a breakthrough in batteries. At least such a problem has existed for a long time in the market of laptops, tablets and smartphones, and its solution has not been successful.
The fourth problem is both an advantage and a disadvantage. It's about about camera ergonomics. As a result of getting rid of “unnecessary elements” of mirror origin, the dimensions have decreased. But they are trying to position mirrorless cameras as a replacement for DSLRs, and the dimensions of the matrices confirm this. Accordingly, not the smallest lenses are used. A small mirrorless camera, similar to a digital compact, simply disappears from view when using a telephoto lens (a lens with a large focal length, strongly approximating objects). Also, many controls are hidden in the menu. In DSLRs, they are placed on the body in the form of buttons. And it's just more pleasant to work with a device that fits normally in your hand, does not strive to slip out and in which you can feel, without hesitation, quickly change the settings. But camera size is a double-edged sword. On the one hand, the large size has the advantages described above, and on the other hand, the small camera fits in any pocket, you can take it with you more often and people pay less attention to it.
As for the fifth problem, it is related to optics. So far, there are many mounts (types of lens mounts to cameras). An order of magnitude fewer lenses were made for them than for the mounts of the main DSLR systems. The problem is solved by installing adapters, with the help of which the vast majority of SLR lenses can be used on mirrorless cameras. sorry for the pun)
Compact camera device
As for compacts, they have a lot of limitations, the main of which is the small size of the matrix. This does not allow you to get a picture with low noise, high dynamic range, blur the background with high quality and imposes a lot of restrictions. Next comes the autofocus system. If DSLRs and mirrorless cameras use phase and contrast types of autofocus, which belong to the passive type of focusing, since they do not emit anything, then active autofocus is used in compacts. The camera emits a pulse of infrared light, which is reflected off the object and back into the camera. The distance to the object is determined by the time of passage of this pulse. Such a system is very slow and does not work over long distances.
The compacts use non-replaceable low-quality optics. A wide range of accessories is not available for them, as for older brothers. The sighting takes place in Live mode View on the display or through the viewfinder. The latter is an ordinary glass, not very good quality, is not related to the camera's optical system, resulting in incorrect framing. This is especially true when shooting nearby objects. The duration of the compacts from a single charge is short, the body is small and its ergonomics are even worse than those of mirrorless cameras. The number of available settings is limited and they are hidden in the depth of the menu.
If we talk about the device of compacts, then it is simple and is a simplified mirrorless. There is a smaller and worse matrix, a different type of autofocus, there is no normal viewfinder, there is no possibility of replacing lenses, low battery life and ill-conceived ergonomics.
Conclusion
Briefly, we examined the device of cameras of various types. I think you now have a general idea of internal structure cameras. This topic is very extensive, but for understanding and managing the processes that occur when shooting with certain cameras at various settings and with different optics, the above information, I think, will be enough. In the future, we will still talk about some of the most important elements: the matrix, autofocus systems and lenses. For now, let's leave it at that.
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How digital cameras work
Most digital cameras have an LCD screen on which you can immediately view the resulting image. This is one of the main advantages of digital cameras. These photos can be viewed on a computer or sent by e-mail.
Digital cameras, in addition to shared memory, also support flash cards that store the pictures you take. You can transfer photos from the camera to a computer or other device either via flash cards (SmartMedia, CompactFlash and Memory Stick), SCSI, USB, FireWire, or via floppy disks, hard drive and CD and DVD discs.
CompactFlash Memory Card Digital photos tend to take up a lot of space. The most common formats are TIFF, unzipped, compressed JPEG (archived), and RAW. In this case, the data is stored in the form in which they were received from the photosensitive matrix. Therefore, the quality of RAW images is significantly higher than the quality of JPEG images, but they take up much more space. Nevertheless, most digital cameras use the high and medium quality JPEG format to store pictures.
Almost all digital cameras have special data compression programs that allow you to reduce the size of photos and free up some space for other pictures. There are two types of compression: compression based on repeating elements and compression based on "extra details". For example, if 30 percent of the photo is blue skies, this means that the photo will have too many repeating shades of blue. Special programs “compress” these repeated colors, so that the photo does not lose its brightness, and there is more free space on the camera. This method allows you to reduce the size of the image by almost 50 percent.
Compression based on "excess details" is a more complex process. As a rule, a digital camera captures more colors than the human eye perceives. Therefore, as a result of such compression, some “unnecessary details”, so to speak, are removed from the picture, due to which the weight of the photo is reduced. Summarizing:
To take a picture, the CCD camera performs the following operations:
First you need to point the camera at a certain object and set the optical zoom, i.e. zoom in or out on an object.
Then lightly press the button.
The camera automatically focuses on the subject.
The camera sets the aperture and shutter speed for optimal exposure.
Then you need to press the button again until it stops.
The camera exposes the CCD and when the light reaches the CCD, it charges each of the elements - pixels individually. This charging further corresponds to an electrical impulse, and thus we get in digital form luminance data for each pixel
An analog-to-digital converter (ADC) measures the charge and creates a digital signal that represents the charge values in each individual pixel.
The processor collects data from various pixels and creates a specific color gamut. On many digital cameras, you can immediately view the resulting image on the screen.
In some cameras, image compression occurs automatically.
Information is stored on one of the types of storage devices, for example, on a flash card.
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