To store pictures in the camera, you cannot do without storage devices. And no matter what they say about the fact that memory has fallen in price several times in recent years, it is still quite expensive. No one complains about “extra” memory; everyone only talks about its lack. Manufacturers usually don’t spoil us with the amount of memory built into the camera, and we have to buy additional memory in ninety-nine cases out of a hundred. After all, a standard eight-megabyte card can hold only eight to twelve images in JPEG format, and even less in the practically incompressible TIFF format. Agree that it is extremely inconvenient to transfer to a computer or keychain with flash memory every six or ten pictures.
Nowadays, most cameras have removable flash memory, which stores information without consuming power and, in addition, allows you to connect a portable high-capacity 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 on 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 will not be able to insert a memory card into it that the camera does not support.
Most slots are designed to prevent the card from being inserted incorrectly (eg upside down). 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, and 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. When 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 result in high cost or even a hindrance in operation. Let us list the information storage devices known today that are used in digital cameras.
For laptop owners, the best choice is PC Card ATA, or, as it is also called by the name of the slot, PCMCIA. Laptops usually have such a connector. This card is used to store large amounts of data (up to 1 GB) and is used as external media, depending on the type, in photo and video cameras and laptops. The size and shape of these cards resembles a thick business card. PCMCIA cards are usually used in large cameras with performance characteristics approaching professional ones.
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 in many ways similar to PC Cards, but its physical dimensions are much smaller. More recently, developments in technology have made it possible to increase its maximum capacity to 1 GB. Compact Flash media has no moving parts and consumes relatively little power - from 3.3 to 5 V, which has made these cards super popular among digital photographic equipment manufacturers. 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 abbreviation 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 the controller found in Compact Flash and other storage devices. So they kind of rely on a controller built into the camera. Smart Media cards have a capacity of up to 128 MB and a size of 45x37x0.76 mm - approximately Matchbox. In addition to reduced compatibility, they have other disadvantages: fragility (the lifespan of the carrier is no more than five years), fragility, vulnerability to external influences and small volume. The latter once seemed sufficient, but today it is quite small compared to what is provided by other media. To transfer images to a computer from Smart Media cards, you need a special Smart Media adapter.
Tiny, the size of a postage stamp, the MultiMedia Card (up to 128 MB in capacity) is one of the smallest small-capacity data storage devices. They were initially conceived for portable telephones, but their small size and weight, as well as a simple interface and reduced energy consumption attracted the attention of manufacturers of various digital devices. MultiMedia Cards are increasingly 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 RAM manufacturers for miniaturization has led to the emergence of a MultiMedia Card variant called RS-MMC (Reduced Size MultiMedia Card, reduced-size multimedia card). The dimensions of RS-MMC have been reduced to 32x24x1.4 mm and are now widely used in smartphones and new generation mobile phones.
Memory Stick memory from Sony with a maximum capacity of 128 MB looks like a piece of chewing gum and weighs only 4 g, but has not yet found widespread use - although the devices for connecting it can be very exotic. Of course: closed standard, high price and small volume. Cameras that use this type of memory are produced only by Sony (they are not compatible with other types of memory).
But SD Cards (Secure Digital Cards), the production of which began quite recently, seem to promise to become very popular media. Today they hold 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 cryptographic protection against unauthorized copying and protection against accidental erasure and destruction. Such properties have attracted 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 MultiMedia Card, which makes the “safe” format even more promising. It is also important that SD Cards consume very little energy and are quite durable.
There are even disposable (non-erasable) flash cards of the Shoot&Store series from SanDisk. Their manufacturer believes that the emergence of such media will contribute to a truly massive transition from film to digital. After all, with the advent of disposable memory, the problem of storing pictures will be solved and the need for a computer will disappear by itself. The cost of disposable flash cards will be comparable to regular photographic film, and the difference in price is compensated by their reliability and ease of selecting frames for printing.
The recently introduced miniature DataPlay data offloading disks are quickly gaining popularity due to their low cost: 500 MB of such memory costs only $10. DataPlay uses smaller DVD optics and a drive similar to a hard drive. In fact, DataPlay can be called a miniature DVD (dimensions 33.53x39.5 mm). DataPlay has announced plans to release devices with a capacity of 4 GB. There's just one thing that's not good: the DataPlay disc is disposable and doesn't allow for re-recording. But how cheap!
Even such media as CD-R discs and CD-RW. Yes, yes, don't be surprised! The CD is inserted into the camera and carries up to 156 MB of recorded data! True, the Sony company, which produces such exotic devices with direct image recording to CD, remains alone on the market for now: no one else is trying to imitate it.
Now, knowing the advantages and disadvantages various types memory, try to evaluate the memory of your camera (or the one you are planning to buy) against the background 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. By mixing up the direction of the contacts, you can damage both the card and the camera.
Protect the card from accumulating static charges. If you have to remove it from the camera, place it on a metal surface or foil from time to time. Do not allow the card to rub against the fabric.
Take special care with your card contacts. Do not scratch or otherwise damage them.
Keep in mind that many cards are quite fragile. If you drop your 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 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. digital camera, which 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 hardware of a computer. Among the components of a digital camera you can find ROM, RAM, modest power consumption CMOS memory, non-volatile flash memory, hard magnetic disk drives (HDDs), more often called “hard drives”, and even such exotic devices as floppy drives and CD drives. R.W.
Obviously, most readers are familiar with the purpose of the above devices - all of them, one way or another, serve for quick or long-term data storage. However, the question may arise as to how these components are used in digital photographic equipment - especially taking into account 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 conduct the discussion chronologically - both regarding the development of the cameras themselves, and regarding the processes occurring in a digital camera.
ROM, RAM and CMOS memory
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 it internal organization will resemble the most primitive computers of that time. The ROM stores both a set of programs that control the “photographic” part (that is, algorithms for calculating exposure), as well as utilities that ensure image formation based on data received from the ADC, as well as subsequent compression of information.
All programs stored in ROM are loaded into RAM after the camera is turned on. Images are also stored here - the Dycam Model 1 did not have non-volatile means of storing information, and when a pair of AA batteries, which were the main source of power for the camera, were discharged, all captured frames were lost. 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 pictures indefinitely (or almost unlimitedly) 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 were somewhat expanded.
The fact is that digital cameras have acquired color. However, this color for each frame had to be restored - interpolated, and for this kind of operation it is necessary RAM, so the pictures still went into RAM, only this time not for storage, but for processing. This processing consisted of forming an image 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.
Not only image processing was performed in RAM. A section of this memory was allocated and assigned to the role of service memory - all camera settings made by the user were stored in it. The first models of digital cameras were quite simple, so the user-selected resolution, compression ratio and flash mode were lost when the camera's power was turned off - adjusting these parameters the next time it was turned on was not difficult. But when the functions of exposure compensation and white balance appeared, it was decided to save the settings made by the user in a section of RAM allocated for service memory - at least until the next battery replacement. With the increase in the resolution of CCD matrices, it became obvious that storing images in the built-in flash memory would obviously limit the user in terms of the available number of frames. Therefore, cameras acquired replaceable flash memory modules, which benefited not only users, but also manufacturers. Firstly, the demand for cameras has increased (it became possible to take them on vacation), secondly, a market for memory modules has emerged, and thirdly, various devices have become widespread that allow reading data from the module without using a camera. These devices, called readers, had a wide variety of designs (they will be discussed in more detail later), although they had one thing in common - they provided access to images organized as files.
Accordingly, another load fell on the camera’s RAM - it was converting the image into one or another file format. The most common files are JPEG, TIFF and RAW formats. It should also be noted that by the time removable media appeared, some manufacturers began to equip their cameras with functions to increase/decrease the brightness, contrast and clarity of the image, as well as convert the image to black and white format. All these transformations were carried out after color restoration and, frankly, much better results could have been achieved using specialized image processing software
Most often, frames are saved in JPEG files. This abbreviation hides the name of an organization (Joint Photographic Experts Group), which has developed a fairly effective information compression algorithm. This algorithm consists of the following steps:
- Converting the color space of an image from RGB (which uses shades of red, blue and green to display all colors) to YUV (where Y is the pixel brightness, and U and V are 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.
- dividing the frame into blocks of 8X8 pixels, followed by discrete cosine transformation of these blocks, which converts the image into a set of harmonic oscillations with different amplitudes and frequencies.
- analysis of amplitude-frequency characteristics for repeatability of color fields, followed by exclusion of 50 percent of brightness and 75 percent of color data.
It is because of this last step that JPEG is classified as a lossy compression algorithm. In other words, even with a 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 increasingly visible in the image - “blurred” boundaries of contrast areas, fragmentation of 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 are very similar to those used in archive programs and ensure 100% image restoration. However, TIFF files take up noticeably more space, even compared to JPEG files with minimal compression, while errors in calculating exposure 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 “impressions” from the CCD matrix without any transformations - first of all, color interpolation is not performed. However, 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 for RAW files, and they are often more compact than TIFF files. And for greater convenience during 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 we need the 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 RAW is best suited for saving 30, 36 or 48-bit images - excess bits can always be used to correct “overexposure” or “underexposure”.
Along with the resolution of CCD matrices, their performance has also steadily increased. Ultimately, the speed of reading data from the sensor became such that it became possible to implement a continuous shooting mode, in which the camera takes a series of pictures 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 increased noticeably. Since then, this type of memory has become known as buffer memory. Along with the continuous shooting mode, models began to be equipped with exposure bracketing, exposure locking, multi-zone autofocus and other useful functions. At the same time, as the resolution increased, the power consumption also increased, so the batteries had to be changed especially often. And each time I had to completely adjust the camera. Users were absolutely not satisfied with this state of affairs; as a result, it was decided to use CMOS memory with very modest power consumption as a service memory - in fact, “one “tablet” (meaning a watch battery) was enough for it. Experienced readers guessed that the solution was borrowed from the world of personal computers, in which motherboard settings are also stored in tablet-fed CMOS memory.
However, what works for a computer doesn't always work for a digital camera. The compartment for the “tablet” took up space in the body, a hatch was required on 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 was ultimately 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 its similarity to ROM, but unlike the latter, flash memory allows modification of the data stored in it. This is achieved by using low voltage when reading information, and high voltage when writing.
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 needed to be uploaded to a personal computer. As file sizes have increased, replaceable memory modules have become widespread, but built-in flash memory in cameras has also remained.
As already mentioned, the use of CMOS memory on tablets as service memory complicated the design and increased the dimensions. Therefore, it was decided to use the camera’s built-in flash memory as a service memory - in this case, the issue of providing power automatically disappeared. Moreover, an opportunity arose to solve two more newly emerging problems.
Firstly, due to the understandable “hasty” of manufacturers (after all, the market needs to be conquered), it often turned out that some functions do not work quite as they should. The same problem occurs with computer motherboards and is “treated” by flashing the firmware. basic system input/output (BIOS), which for some time now has been stored not in ROM, but in flash memory. This decision has migrated to digital cameras, and now to correct “inappropriate behavior” when calculating exposure or focusing, it is enough to acquire the latest software “patch” and “overlay” it on the built-in software camera stored in flash memory.
Secondly, the increase in matrix resolution had a negative impact on production volumes - an increasing percentage were scrapped due to the abundance of “stuck” pixels. At the same time, the demand for digital photographic equipment continued to grow. Therefore, the rejection standards were made more liberal, and so that users would not be embarrassed by “stuck” pixels, cameras began to be equipped with a mode that scans defective elements of the CCD matrix and stores their coordinates in service flash memory. And when generating a full-color image, elements included in the “list of stuck pixels” were excluded from consideration.
Replaceable flash memory modules
So, by the time the resolution of CCD matrices reached 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 “DSLRs”.
It was in the Kodak DCS-420 SLR digital cameras of 1994 that slots designed for installing PCMCIA cards first appeared. In turn, these cards equipped with flash memory were developed even earlier for laptop 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, as well as 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 PCMCIA slots were more suitable for impressive-sized DSLRs, there was also a place for them in the bodies of some amateur cameras - for example, the Kodak DC-50. However, the CompactFlash standard that appeared in 1994, which became a development of PCMCIA, achieved much greater success.
The appearance of cards of this type was made possible by increasing the recording density in flash memory chips. As a result, the size of the chips decreased, 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, electrically CompactFlash modules were fully compatible with their predecessors. And for mechanical compliance, a CompactFlash-PCMCIA adapter in the form of a PCMCIA card was sufficient, 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 pictures directly into the computer, without using any connecting wires or software to exchange data 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 - Type II CompactFlash 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 the foresight of the standard developers once again deserved praise.
The fact is that the memory controller was located directly in the CompactFlash module, much the same as in hard drives. Thereby newest maps increased capacity could be installed in a relatively old camera. This flexibility has given the CompactFlash standard unsurpassed longevity.
However, placing the controller on the map also has disadvantages. Firstly, the cost of the device increases. Secondly, as a result, manufacturers have a “free hand” and they label cards indicating “unformatted capacity” (for example, “64 MB”), although in reality only 60 to 63 MB remain free for storing data.
After the spread of the USB interface, CompactFlash-USB data readers became popular. Moreover, CompactFlash modules appeared that had a chipset that implemented a 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 the computer without any additional devices.
Perhaps, in the field of minicomputers, CompactFlash modules have become no less widespread than in digital photographic equipment. Moreover, the reserves built into the interface (in truth, 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 distinguished by its high popularity, good exchange speed and large reserves for increasing memory capacity.
Question long-term storage Digital photography is a little deeper than it might seem at first glance. Unlike “operative” files, a digital photo archive must be guaranteed to remain intact for years and decades. It would seem, what could be simpler? There are many different media available: optical CDs, DVDs and BlueRay (BR) discs, all kinds of flash drives and memory cards, regular hard drives and even remote file storage services, so-called file sharing services. The main problem with long-term storage of digital images is the reliability of the media, while capacity, speed or ease of use fade into the background. It is also worth remembering that when choosing a storage medium, you should take into account the frequency of accessing files. It’s one thing to have an optical disc locked in a safe “forever”, and a completely different thing to have a constantly updated family album. As usual, if we win in one thing, we lose in another, the law fully applies to information carriers. Unfortunately, the ideal storage facility has not yet been invented. Let's try to understand today's abundance and help make conscious choice without relying on advertising.
Volume. In fact, the more the better, it doesn't hurt to have some extra. But if your budget is limited, you can estimate the required storage capacity based on the total number and volume of photographs. The author only accepts archives in uncompressed formats, such as TIFF. In the common JPEG, the photo volume is approximately 5 times smaller. It’s very easy to calculate: divide the storage capacity by the volume of the photo. The first is written on the device itself, and the approximate volume of the scanned photograph can be estimated from the plate (the dimensions indicated 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 |
Carriers. The most compact and, probably, the most common storage medium is the so-called flash memory. Tiny microcircuits are found in memory cards, flash drives and mounted in various equipment. This type of memory is good for its energy independence, relative cheapness and capacity - today you won’t surprise anyone with a 256 GB USB flash drive. The disadvantages include low exchange speed 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 “ideal”, which probably cannot be provided by any a common person. Stable temperature, humidity and even atmospheric pressure. Absence of radiation, both radio frequency and radioactive. No memory accesses during the retention period. These are the “normal” conditions from the point of view of manufacturers... With normal use, individual bits of information can be lost 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 quick data storage and, with reservations, for long-term storage. There is one caveat, but an important one: you need 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 to last for many years. It is better to buy memory from famous brands such as Kingston, Transcend, Sandisk and others that provide a guarantee of at least three years.
Optical discs have been widely used for decades and have undergone only three key stages of evolution - CD, DVD and BlueRay technologies. Only a specialist can distinguish disks of different generations by appearance, but their capacity differs 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 one will fit approximately 20 large photos, on the second - about 200, and accordingly on the third - around 1500 images. It should be noted that BlueRay media is quite expensive in itself, and recording equipment is affordable only for very wealthy people. CDs are already becoming a thing of the past, and today's leader in this field - DVD - is available to everyone. Therefore, BR disks cannot yet be called widespread as home archive storage. About reliability. Here the bar is set by the material itself - a transparent plastic disk. Obviously, plastic is afraid of elevated temperatures (disc deformation) and mechanical stress (the surface is scratched). Both prevent you from reading the information correctly. But the number of reading cycles is almost infinite, and optical media indifferent to any type of radiation. From this we can conclude that DVDs, and in the near future also 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 for one DVD disc can take 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” and the like in the name, indicating increased storage reliability.
Hard disks- “hard drives” have long been firmly established in the niche of online storage of information. Modern technology allows you to create media with a capacity of up to tens of Terabytes (!), where you can record any imaginable photo archive. Hard drives provide high data transfer speeds, great amount rewrite cycles at a low price and acceptable reliability. But it should be remembered that a hard drive is a complex and precise mechanical device, even a high-tech one. Therefore, storage reliability is determined both by operating conditions and the quality of a particular specimen. Since magnetic recording is used, hard drives are “afraid” of strong magnetic fields and mechanical overloads, especially during operation. Restoring failed media can be very expensive or even beyond the capabilities of the technician. But in more or less comfortable conditions, a hard drive is almost ideal for storing a photo archive, even one that is constantly updated. Moreover, there are simple ways to increase storage reliability by an order of magnitude - using several hard drives simultaneously in a so-called RAID array. The array can be organized on most home computers, or you can purchase a specialized device (usually within $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, and constantly monitors the condition 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 over, because even one hard drive is very reliable and can work for many years without turning off. The disadvantages of this solution include cumbersomeness, high price, plus the need for some knowledge of computer hardware and software settings. These shortcomings are more than compensated for by the speed and reliability of the archive in average home conditions. 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 storages. With the development of the Internet, numerous file hosting services have appeared - sites on which you can upload your documents (no matter whether photos, videos or just files) within the allocated quotas and at any time access files through any computer connected to global network. Usually a very modest volume is provided for free, which can be expanded for the same modest money. Services vying with each other to boast about the reliability and security of data - and many are not unfounded. Large companies can afford the most modern and super-reliable file storage under the supervision of experienced specialists. System administrators do everything to prevent personal drives from being hacked. And yet, who can guarantee that in ten years this company will still exist? Who guarantees that there won’t be a hacker who, out of hooligan motives, will post your personal files for everyone to see? And today you have access to the network, but tomorrow you don’t. And yet, remote storage is very convenient, especially in conjunction with a fast Internet and is great for accumulating, updating and creating an archive, which in turn will be saved on a more suitable medium. I deliberately do not provide links, since I have no information about the reliability of this or that service. I myself use the foreign “DropBox” - it seemed convenient, and the service is no longer new.
And finally, in general, Very important rule , valid regardless of the type of storage media selected: MAKE BACKUP COPIES! That's right, in capital letters! Even if you’re lazy, don’t have time, or it’s expensive, make copies on different media as soon as possible. Personally, the author’s main archive, which is “for centuries”, lies on two dozen DVDs, with each disc in duplicate. The operational archive is on the RAID array of your home computer, and the most valuable files are duplicated on remote storage on the Internet. Instead of an array, you can use a couple of large flash drives or external hard drives, just be sure to make copies of everything and don’t be lazy. Remember that restoring damaged storage media 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 have something in common with the previous one. For everyone else, I will repeat the summary once again. There are three types of cameras: compact, mirrorless and DSLR. 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 DSLR cameras.
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 you need to understand the main components and operating principle. This will allow you to look at the camera from a different perspective - 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 next and how the final result is obtained. Compact cameras We won’t touch on it, but let’s talk about DSLR and mirrorless devices.
SLR camera design
Globally, a camera consists of two parts: a camera (also called the body) and a lens. The carcass looks like this:
Carcass - front view
Carcass - top view
And this is what the camera looks like complete with a lens:
Now let's look at the schematic image of the camera. The diagram will show the structure of the camera “in cross-section” from the same angle as in the last image. The numbers on the diagram indicate the main components that we will consider.
After adjusting all the settings, 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 matrix 2. This time is called shutter speed. It is also called the matrix exposure time. Key shutter characteristics: shutter lag and shutter speed. Shutter lag determines how quickly the shutter curtains open after you press the shutter button - the lower the lag, the more likely it is that that car rushing past you that you're trying to capture will be in focus, not blurred, and framed the way you did when using the viewfinder. For DSLRs and mirrorless cameras, the shutter lag is small and is measured in ms (milliseconds). The shutter speed determines the minimum amount of time the shutter will be open - i.e. minimum shutter speed. On budget cameras and mid-level cameras, the minimum shutter speed is 1/4000 s, on expensive ones (mostly full-frame) – 1/8000 s. When the mirror is raised, light does not enter either the focusing system or the pentaprism through the focusing screen, but directly onto the sensor through the open shutter. When you take a shot SLR camera and at the same time look into the viewfinder all the time, then after pressing the shutter you will temporarily see black spot, not an image. This time is determined by the shutter speed. If you set the shutter speed to 5 seconds, for example, then after pressing the shutter button you will see a black spot for 5 seconds. After the matrix is exposed, the mirror returns to its original position and light again enters the viewfinder. IT IS IMPORTANT! As you can see, there are two main elements that regulate the flow of light entering the sensor. This is aperture 2 (see previous diagram), which determines the amount of light transmitted, and the shutter, which regulates shutter speed - the time it takes for light to hit the matrix. These concepts are at the heart of photography. Their variations achieve different effects and it is important to understand their physical meaning.
Camera matrix 2 is a microcircuit with photosensitive elements (photodiodes) that react to light. In front of the matrix there is a light filter, which is responsible for obtaining a color image. Two important characteristics of the matrix are its size and signal-to-noise ratio. The higher both are, the better. We will talk more about photomatrices in a separate article, because... this is a very broad topic.
From the matrix, the image goes to the ADC (analog-to-digital converter), from there to the processor, processed (or not processed if shooting in RAW) and saved to a memory card.
Another important detail of DSLRs is the aperture repeater. The fact is that focusing is done with the aperture fully open (as far as possible is 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 depth of field remains constant. To see what the output frame will be like, you can press the button, the aperture will close to the set value and you will see the changes before pressing the shutter button. An aperture repeater is installed on most DSLRs, but few people use it: beginners often don’t know about it or don’t understand its purpose, while experienced photographers know approximately 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 design
Let's immediately look at the diagram and discuss in detail.
Mirrorless cameras are much simpler than DSLRs and are essentially their simplified version. They do not have a mirror and a complex phase focusing system, and also have a different type of viewfinder.
The light flux enters through the lens onto matrix 1. Naturally, the light passes through the diaphragm in the lens. It is not indicated on the diagram, but I think, by analogy with DSLRs, you guessed where it is located, because the lenses of DSLRs and mirrorless cameras are practically the same in design (except perhaps in size, mount and number of lenses). Moreover, most lenses from DSLRs can be installed on mirrorless cameras via adapters. Mirrorless cameras do not have a shutter (more precisely, it is electronic), so the shutter speed is adjusted by the time during which the matrix is turned on (receives photons). As for the matrix size, it corresponds to Micro 4/3 or APS-C format. The second is used more often and fully corresponds to matrices built into DSLRs from the budget to the advanced amateur segment. Now full-frame mirrorless cameras have begun to appear. I think that in the future the number of FF (Full Frame) mirrorless cameras will increase.
In the diagram, number 2 indicates the processor, which 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, this is not difficult to do in mirrorless cameras, because the light flow is not blocked by the mirror, but flows freely onto the matrix.
In general, everything looks just great - complex structural mechanical elements (mirror, focusing sensors, focusing screen, pentaprism, shutter) have been removed. This made production much easier and cheaper, reduced the size and weight of the devices, but also created a lot of other problems. I hope you remember them from the section on mirrorless cameras in the article about. If not, then now we will discuss them, simultaneously examining what technical features caused by these shortcomings.
The first major problem is the viewfinder. Since the light hits the matrix directly and is not reflected anywhere, we cannot see the image directly. We see only what gets onto the matrix, then is incomprehensibly 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 right away, 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 cannot be compared with the resolution of the eye. Electronic viewfinders tend to become 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 pure image passed through a series of mirrors will go into oblivion just like “correct film photography.”
The second problem arose due to the lack of phase detection autofocus sensors. Instead, a contrast method is used, which determines by contour what should be in focus and what should not. In this case, the objective lenses move a certain distance, the contrast of the scene is determined, the lenses move again and again the contrast is determined. And so on until maximum contrast is reached and the camera focuses. This takes too much time and is less accurate than a phase system. But at the same time, contrast autofocus is a software function and does not take up additional space. Nowadays they have already learned to integrate phase sensors into mirrorless matrices, creating 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 fact that it is stuffed with electronics that are constantly working. If the photographer is working 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 recordings. By the way, the latter (I’m talking about the viewfinder) also consumes energy, and not a little, because its resolution is high and brightness and contrast should be at the same level. I note that with increasing pixel density, i.e. when their size decreases with the same power consumption, brightness and contrast inevitably decrease. Therefore, powering high-quality, high-resolution screens requires a lot of energy. Compared to DSLRs, the number of frames that can be taken on a single battery charge is several times less. For now, this problem is critical, because it will not be possible to significantly reduce energy consumption, and we cannot count on a breakthrough in batteries. At least this problem has existed for a long time in the market of laptops, tablets and smartphones and its solution has not been successful.
The fourth issue presents both an advantage and a disadvantage. It's about about camera ergonomics. Due to the removal 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 size of the matrices confirms this. Accordingly, lenses of not the smallest size 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, bringing objects very close). Also, many controls are hidden in the menu. In DSLRs they are placed on the body in the form of buttons. And it’s simply more pleasant to work with a device that fits well in your hand, doesn’t tend to slip out, and in which you can quickly change settings by touch without thinking. But camera size is a double-edged sword. On the one hand, a large size has the advantages described above, and on the other hand, a small camera fits into 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. There are currently many mounts (types of lens mounts for cameras). There are an order of magnitude fewer lenses made for them than for the mounts of the main DSLR systems. The problem is solved by installing adapters, with which you can use the vast majority of DSLR lenses on mirrorless cameras. Sorry for the pun)
Compact camera design
As for compacts, they have a lot of limitations, the main one of which is the small size of the matrix. This does not allow you to get a picture with low noise, high dynamic range, high-quality blurring of the background and imposes a lot of other restrictions. Next up is the autofocus system. If DSLRs and mirrorless cameras use phase and contrast types of autofocus, which are classified as a passive type of focusing, since they do not emit anything, then compacts use active autofocus. The camera emits a pulse of infrared light, which bounces off the object and back into the camera. The travel time of this pulse determines the distance to the object. This system is very slow and does not work over significant distances.
Compacts use non-replaceable low-quality optics. A wide range of accessories is not available for them, as for their older brothers. Sighting occurs at Live mode View on the display or through the viewfinder. The latter is ordinary glass, not very good quality, is not connected to the camera's optical system, resulting in incorrect framing. This is especially noticeable when shooting nearby objects. The operating time of compacts on a single charge is short, the body is small and its ergonomics are much worse than those of mirrorless cameras. The number of available settings is limited and they are hidden deep in the menu.
If we talk about the design of compacts, then it is simple and is a simplified mirrorless camera. It has a smaller and worse matrix, a different type of autofocus, no normal viewfinder, no ability to replace lenses, low battery life and ill-conceived ergonomics.
Conclusion
We briefly looked at the design of various types of cameras. I think now you have a general idea about internal structure cameras This topic is very broad, but to understand and control the processes that occur when shooting with certain cameras at different settings and with different optics, I think the above information 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 photo. This is one of the main advantages of digital cameras. Such photographs can be viewed on a computer or sent by e-mail.
In addition to shared memory, digital cameras also support flash cards on which the pictures you take are saved. You can transfer photos from the camera to a computer or other device via flash cards (SmartMedia, CompactFlash and Memory Stick), SCSI, USB, FireWire, as well as via floppy disks, hard drives and CD and DVD drives.
CompactFlash Memory Card Digital photos tend to take up a lot of space. The most common formats are TIFF, unzipped, compressed JPEG (zipped), and RAW. In this case, the data is saved in the form in which it was 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 images.
Almost all digital cameras have special data compression programs that can reduce the size of photos and free up some space for other photos. There are two types of compression: compression based on repeating elements and compression based on “extra parts”. For example, if 30 percent of a photo is blue sky, that means there will be too many repeating shades of blue in the photo. Special programs “compress” these repeating 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 "extra parts" is a more complex process. Typically, a digital camera captures more colors than the human eye can perceive. Therefore, as a result of such compression, some so-called “excessive details” are removed from the picture, due to which the weight of the photograph is reduced. Summarizing:
To take a photo, a CCD camera performs the following operations:
First, you need to point the camera at a specific object and set the optical zoom, i.e. bring an object closer or further away.
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 all the way again.
The camera exposes the CCD and when light reaches the CCD, it charges each of the elements - the pixels - individually. This charge subsequently corresponds to an electrical impulse, and thus we get in digital form data on the illumination of each pixel
An analog-to-digital converter (ADC) measures the charge and creates a digital signal that represents the charge values at each individual pixel.
The processor collects data from various pixels and creates a specific color scheme. On many digital cameras you can immediately view the resulting image on the screen.
Some cameras compress images automatically.
Information is stored on one type of storage device, for example, a flash card.
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