Sigma Foveon X3 principles of three-tier PC

Full color images of FOVEON X3 sensor chip is in the various types of digital cameras, the first and only full-color images of the intake system. Contains three-tier distribution arrangement with pixel (Pixel) images color cast measuring chip (SI), the image of the shade by sensing body, different colors of light spectrum, the direct head is located in the FOVEON X3 imaging chip, according to the different wave frequency, absorbed in different depth

Full color images of FOVEON X3 sensor chip is in the various types of digital cameras, the first and only full-color images of the intake system.

Contains three-tier distribution arrangement with pixel (Pixel) images color cast measuring chip (SI), the image of the shade by sensing body, different colors of light spectrum, the direct head is located in the FOVEON X3 imaging chip, according to the different wave frequency, absorbed in different depth level sensing body. Formation of 3 layers of red, green and blue color layer to ensure 100% RGB light is admitted without computer simulation of interpolation. By comparison with the traditional sensor lenses, shot better: color granularity higher, less artificial colors and image sharpness strong 3 times. SIGMA SD10 digital SLR-unique FOVEON X3 1,029 full color image sensing million chips; the image of each pixel is more sophisticated, full-color more realistic and sharper resolution, absolute is outside the traditional CCD or CMOS and other sensor chip. So when you in different circumstances, have access to detailed images of colorful photos.

SIGMA SD10 differentiators, is both accurately taking 100% red, blue, green (RGB) color light.

But the traditional CCD and CMOS single is a single photosensitive layer by mosaic (Mosaic) fliter taking shade, each and every pixel (Pixel) can only record one of the primary colors of light (red or blue or green), the other two primary colors of light reflection and wastage caused only blank, fill the blank address by computer simulation of interpolation not true of false positives. Tone-led color distortion, computer noise, insufficient resolution. But the FOVEON sensor full color image X3 chip can simultaneously capture RGB light for each pixel in the image, ensure that color and truthfully make show. Therefore, the SIGMA SD10 is in the same picture in the effect is three times the other brands of digital cameras, SD10 have 1,370 painting of supernatural power.

Traditional single CCD/CMOS sensor, is the use of color filter (color filter), each picture in the induction of different colors, and then apply these colors into a valid picture.

Traditional image sensing modalities, in a single photosensitive layer must pick the three RGB light, therefore, it is designed to be arranged, mosaic-the end result is that the Green light to capture 50% of the amount of light, the Red and Blue 25% of the amount of light to capture. Each picture in the induction of different colors, and then through the math to color simulation into image, the effect is greatly reduced. Sigma SD10 due to discard the irregular distribution of color filter (mosaic color filter), the image will be sharper. And its effective art-more than the original design of 343 million pictures in a resolution of more than three times. FOVEON X3 three photosensitive layer, in different depth capture RGB light, so you can ensure that only retrieve RGB color is 100%. Tiered photosensitive will have several key advantages, for example, more fresh, sharp, color detail increases, you can avoid unnecessary striatum effect ... And so on.

Presented in the Foveon x technology, allowing electronic technology successfully imitate true negatives of colour theory, according to the wavelength of light absorption by colour, the corresponding old mosaic technology a picture of one color only induction-red and blue light only capture 25%, the green light to capture 50% of the defects of the same painting X3 sensors can be in three different colors, greatly improves image quality and color performance.

There is also a characteristic X3, support more powerful computing technology VPS (Variable Pixel Aize), a similar level of vertical SuperCCD III operations consolidation, also through the Group art of mix to reach. You can achieve ultra-high X3 ISO value (must be subtracted resolution), as well as high-speed VGA recording picture rate. Simply put, X3 separations for RGB colors are configured with a 3-layer sensor, with a single picture in original identification 3 color, thus bridging the digital camera often pseudo color phenomenon.

The 7 megapixel camera what advantages?

Recently, the compact digital cameras have also introduced a 700 MB contributory. However, I think the 7 megapixels is too high, it seems unnecessary. I ask, what are the advantages the 7 megapixels? now even small and lightweight digital cameras also took 700 megapixel era. However, as you ask, the 7 megapixels really necessary? pixels less digital camera prices also phase

Recently, the compact digital cameras have also introduced a 700 MB contributory.

However, I think the 7 megapixels is too high, it seems unnecessary. I ask, what are the advantages the 7 megapixels?

Now even small and lightweight digital cameras also took 700 megapixel era.

However, as you ask, the 7 megapixels really necessary? pixels less digital camera price is the lower. "Can reduce pixels, so that the camera cheaper"--If you think it is also understandable. Next, we'll take a look at 700 m pixel image at what time can come in handy.

The number of pixels by impact print size.

High-megapixel digital camera capable of shooting image size larger photos. The larger the image size, you can print to the larger sizes of paper. Even if it is part of the image cropped down to print, can be printed as a fine result. However, it was generally believed that "for L-size paper, 130 megapixel image is sufficient". This is why?

Print fine effect depends on the "DPI (dots per inch)" this index.

For a printer, it represents the "many points can be printed. The higher the number the more precise printing results. In General, more than the prints precision 300dpi, basically there is no problem. As for the latest inkjet printer, as long as we can get enough 200dpi pretty print effects.

Calculation of the desired image size

Here, we calculate to 200dpi print the desired image size.

The calculation formula is 【 the image dimensions (width/height) 】 = 【 print size (width/height) cm 】 ÷ 【 2.54 】 × 【 dpi 】. The reason is that by dividing 2.54 will be carried out with the cm units in inches (1 inch = 2.54cm). The data to be substituted into the formula, you will come to 200dpi in L-size paper (12.7 × 8.9cm) when printing on the desired image size is 1000 x 701 pixels. Due to the mega-image resolution is 1280 × 960 pixels, so that "L size, 130 Megapixels is enough". So, if you are A4 size (29.7 × 21cm) print? use the same calculation to know that you want to print need 200dpi 2339 x 1654 pixels. In this way, 400 megapixel image is sufficient. Therefore, the 7 megapixels (3072 × 2304), nature is a bit high.

7 megapixels-big size images can play a role of occasions is part of the image to be enlarged print.

Please see the following figure. 7 megapixels, respectively, preparing and 400 megapixel 2 images that will cut out the middle section, the print to the printer paper size L. If you are cut out 700 megapixels, the component is unable to print, the effect 200dpi is very beautiful. And 400 pixel image can be printed, 200dpi following effects seem a bit rough. Collective license and cannot zoom shot, hope will be a part of the image to enlarge the print, the 7 megapixels you can come in handy.

The Conference will be a part of the image down to print, the more pixels, the better the effect

Ready to 700 megapixels and 400 megapixel 2 images, respectively the intermediate dog Photo CD down after printing to L size paper.

From 700 megapixel image on the CD off to 200dpi granularity print to L size paper, so the effect was very good. But megapixels, as the resolution is insufficient, the printed results becomes rough.

FUJIFILM exclusive Super CCD and General comparison traditional CCD

To purchase a FUJIFILM digital camera a lot of friends has a doubt is the SUPER CCD and generally have a CCD and different, especially the SUPER CCD with ultra-high output painting pigment, this ultra high art and some use software plug points differ, today we are going to introduce you to these two PC components. First SUPER CCD output picture-not use virtual or

To purchase a FUJIFILM digital camera a lot of friends has a doubt is the SUPER CCD and generally have a CCD and different, especially the SUPER CCD with ultra-high output painting pigment, this ultra high art and some use software plug points differ, today we are going to introduce you to these two PC components.

First SUPER CCD output picture-not use virtual or software plug point, many traditional shops as for the structure of the SUPER CCD does not understand that in order to save explanation or don't know, so I'll tell you what is virtual, it is not a general use virtual or software plug point a digital camera can match.

1. a light area

Traditional CCD Super CCDSuper CCD optical area is approximately equal to traditional CCD optical area 2 x principle: Super CCD sensor diode Control signal path (control signal channel) took off 1 Super CCD sensor diode light an area equal to 2 traditional CCD area affected by light.

Traditional CCD super CCD

2. the light efficiency Fuji Super CCD sensor with unique octagonal diode, digital camera lens is circular, octagonal Super CCD as closer to the circle, so the light efficiency than traditional CCD high square, can effectively guarantee the quality of digital images and photographic images added to balance sensitivity, the more of images and also dramatic effects can improve sexual noise ratio, increasing the image resolution, image fidelity and clarity.

As the third-generation Super CCD sensor, its performance with greater improvement and advancement, but also makes this sensor digital cameras on the market with a strong competitive strength.

3. the arrangement CCD alignment rotate 45 degrees, which increase 60% resolution for the human eye's perception, the same number of photosensitive diode rotate 45 degrees of the arrangement will increase than square arrangement (5-3)/3 = 67%.

Traditional CCD hierarchy (gradation) less traditional CCD color sampling only 24 BitSuper CCD hierarchy (order transfer) is the traditional CCD 4096 x Super CCD color sampling, up to 36 Bit

The advantages of 4.SUPER CCD

A, image quality reference noise reduction (meter noise ratio lifting 130%), the image noise is a transport channel in resistors, Super CCD of light area increase, that is, each picture element (pixel) of the charge (charge), signalling increased, so (signal + noise)/noise = hearing noise ratio lifting 130%

B, smoother animation quality

Understanding digital zoom and the optical zoom

Talk about 「introduction lens, lens focal length 」 is a camera shot of one of the most important characteristics, in order to allow traditional photographers easily understand consumer-level digital camera lens of significance, we are often converted into equivalent focal length 135 camera. 「Cold lens 」 refers to parallel rays after passing through the lens, the focal point of the collection to the distance between the lens. Basically, if it is

Talk about 「introduction lens, lens focal length 」 is a camera shot of one of the most important characteristics, in order to allow traditional photographers easily understand consumer-level digital camera lens of significance, we are often converted into equivalent focal length 135 camera.

「Cold lens 」 refers to parallel rays after passing through the lens, the focal point of the collection to the distance between the lens. Basically, if it is the position of the camera body, lens focal length and objects using the magnification will render a proportional relationship.

Namely: magnification = image size/absorbed body size optical zoom

So, like the Nikon CoolPix 990 digital camera lens focal length is 38 mm-115mm (the equivalent of 135 camera), we would say that it is 3X of optical zoom, meant that the original lens for 38 mm, a lens system with telescopic changes, the maximum you can adjust the lens focus to 115mm.

At the same shooting distance, you will be taken three times the volume amplification.

Digital zoom digital cameras today have evolved into a small computer with operating system in General, internal, you can do one of the established procedures.

Through the firmware on the program's calculus and optical systems, we can be taken in making local amplification to interpolation mode simulation out Optical Zoom effect. 「Cold digital zoom 」 will wear out image quality, in the General conditions of shooting, we do not recommend using 「introduction digital zoom 」. But we also know 「introduction poor photo 」 than 「introduction no photo 」, in certain special circumstances, we will spend 「introduction digital zoom 」.

Optical zoom VS digital zoom optical zoom of the image quality is better than digital zoom, please try to take the optical zoom function.

Optical zoom and digital zoom calculation: If a camera's optical zoom as 3X, digital zoom for 4X, the camera combined with optical zoom and digital zoom function, you can reach the enlarged capacity 12X (though ... This is not very practical).

Fixed focus and zoom no matter what factories camera, 「introduction zoom 」 features the same will result in the loss of image quality, therefore, a sibling of a digital camera/lens system, lens 「introduction focusing 」 taken as a result, should be better than lenses 「business zoom 」 also sharp!, on the other hand, the lenses 「business focusing 」 easier design, lower cost, but in the composition, no 「introduction zoom 」 lens so convenient.

Increasing distance lenses for the same reason, 「introduction increase from microscopic 」 usage increased amplification rate, may result in image quality decreases, in General, we recommend users to try not to use more than 2X of 「introduction increase from microscopic 」.

However, the use of 「introduction increase from microscopic 」, the effect will still be better than 「introduction digital zoom 」.

Optical anti-shake and nature anti-shake comparison

Why use anti-shake has just started to use digital camera friends often encounter problems: your own shooting out of the picture is not clear enough, always occur ghosting or fuzzy. This is why? in addition to the occasional loss of focus (that is, the camera fails to correctly focus), largely because of the shutter speed is too low. In General, in the handheld, shooting to the Qing dynasty

Why use anti-shake

Just started to use digital camera friends often encounter problems: your own shooting out of the picture is not clear enough, always occur ghosting or fuzzy.

This is why? in addition to the occasional loss of focus (that is, the camera fails to correctly focus), largely because of the shutter speed is too low. In General, in the handheld, shooting to clear photos of shutter speed should reach the focal distance countdown or even higher.

In actual shooting, the photographer's hand in film or CCD/CMOS photographic process of jitter is objective and existent, prevention is prevention, can only rely on the machine's special "anti-shake" function to decrease as the photographer's hand jitter caused by image blur.

Anti-shake technology analysis

Currently, anti-shake three types: optical anti-shake, sensor (CCD) anti-shake, natural anti-shake (ISO anti-shake).

Optical anti-shake is dependent on the lens of the gyroscope detects tiny mobile and will signal transmission to the microprocessor immediately evaluated need compensation of displacement, and then through the lens group, under the direction of the camera jitter and displacement quantity to be compensated, thereby effectively circumvent the camera vibration generated image blur.

Photoreceptor anti-shake CCD principle is — the anti-shake is housed in a CCD can move around on the bracket of the first detect whether dithering, and sensors detect dithered direction, speed, move the volume ...

Detection of signal processing to calculate can offset jitter of CCD amount to achieve the anti-shake is moved.

The above principle of two anti-shake is similar, namely through the camera's internal staff of mechanical movement to compensate jitter to achieve the anti-shake effect.

At the same time, the anti-shake technology will result in lower Imaging sharpness. After all, the speck much floating lenses, which require high photographic enthusiasts, it is not good; so this is why the anti-shake system will have a switch, users can select Cancel or turn the anti-shake; plus the anti-shake system is very low, so you generally do not open the anti-shake switch, but only when you want to use to open, if instant capture moving objects that may be because many of these steps and missed opportunity.

Natural anti-shake is ISO anti-shake.

His research interests at the time of the adoption of genuine e-mail. That is, increase the ISO, shutter speed reached anti-shake.

Because the camera has a security shutter (that is, ensure that the image is not blurry shutter speed), the general sense of security shutter speed to 1/60 second, lower than the shutter speed is likely to be photographed image blur.

Suppose that in the same scene under the same display, the exposure is the same (same screen environment definitely identical exposure no doubt), if the aperture unchanged, if ISO improves, inevitably lead to shutter speed so that the original did not reach the security shutter shutter speed, ISO increase of cases it is possible to reach even more than security shutter, natural anti-shake is achieved through such a tad better. The anti-shake effect compared to the other two anti-shake effect even have gone.

Anti-shake optical anti-shake VS nature

Test conditions

Let's choose a price equivalent, with optical anti-shake function of other brand camera (A) and a digital camera with natural anti-shake (hereinafter B) do the comparison, in the same fluorescent circumstances, adopt the following props, can swing to the left is the "head" on the right you can move the "platform", in the same frequency shaking, I made the following three conditions test: the camera moved

JPEG image format

JPEG image format JPEG (Joint Photographic Experts Group) is the most common digital image formats. .JPEG wide range of application, including the world wide web browser, image processing software and so on. .JPEG format used in digital camera photos, it can compress the photo file size to 10% to 20%. .Compared to the original uncompressed image, JPEG image format <P> </ P> <P> JPEG (Joint Photographic Experts Group) is the most common digital image formats. .JPEG wide range of application, including the world wide web browser, image processing software and so on. .JPEG format used in digital camera photos, it can compress the photo file size to 10% to 20%. .Compared to the original uncompressed image, JPEG image quality degradation and loss of detail is not obvious. .</ P> <P> theoretical summary </ P> <P> In short, JPEG the image information (color and other details) to re-schedule, which compressed the color details of the degree of compression than the large, because our eyes on .details of the change in the color change than the high degree of sensitivity. .Then, JPEG to the details of the information classified as meticulous details and coarse detail. .As our eyes on the rough details of the changes in more sensitive, so fine details will be discarded. .JPEG is through a complex series of mathematical operations and the compression method, without serious damage to the case of quality, compressed image size. .The more complicated mathematics and compression methods, without knowledge of the reader may feel that obscure, so we did not in the glossary which records the content. .Interested readers can refer to a more professional image processing books and articles. .</ P> <P> instance </ P> <P> JPEG image file size and image quality between a good balance. .JPEG compressed image, the image processing is divided into one square area, area size is 64 pixels (8 x 8), each region is independent compression. .In the case of small degree of compression, the edge of each region there is a "hair-like" unnatural signs; when the compression level increases, more and more obvious of these signs, we can even see and distinguish the various regions. .Detailed Look at the example of the magnification factor of these pictures is 2. .</ P> <P align=center> </ P> <P> 100% quality compressed JPEG image is difficult to distinguish between the original image, but the original JPEG image file size is only 1 / 6. .</ P> <P align=center> </ P> <P> 80% quality compressed JPEG image quality is still good (remember, after twice the figure is the enlarged image), and its file size is only .the original file to 1 / 10. .Please note that the yellow crayon in the edge of the screen a bit fuzzy fade. .Most digital cameras to provide users the option to JPEG compression level, of which "the highest-quality JPEG" quality level is often higher than 80%. .</ P> <P align=center> </ P> <P> 60% quality compressed JPEG images. .If the reader to look carefully, you will find JPEG compression between the regional and unnatural "hair-like" compression marks. .While the quality decreased, but 60% of the quality of the JPEG compression has been used for the page is enough. .Its size is the original file size of 1 / 20. .</ P> <P align=center> </ P> <P> 10% quality compressed JPEG images, JPEG compression area is clearly visible, image quality decreased significantly. .This low-quality JPEG images only use is to allow us to understand principles of JPEG compression (high quality JPEG compression is difficult to see the area), and of course we would not normally compress the image so powerful. .</ P> <P> practical tips </ P> <P> <1> we edit images, it is best to "middle image" (for example, TIFF, PSP and PSD, etc.) stored for later .use. .If you save an image directly to the JPEG format, and then the file is closed, then open to the same compression quality setting the image then save the image does not become a ... ... a small, but the image quality will decline further. .Therefore, we should be processing the image, fishes pictures to be compressed. .</ P> <P> <2> Digital cameras usually have quality JPEG compression options, such as fine, medium, basic ... ... unless you shoot with RAW or TIFF format, or use the best quality setting. .Some digital cameras, even if choosing the best quality compression, it is still very high degree of image compression. .</ P> <P> Reference: <U> RAW image format </ U> <U> TIFF image format.

Interpolation (Interpolation).

Interpolation (Interpolation / resampling) is an image processing method, which can increase or decrease the digital image pixel number. .Some digital cameras use to create a pixel interpolation method to produce than the actual pixel multi-sensor images, or create images generated by digital zoom. .In fact, almost all of the image processing software to support one or more interpolation. .<P> Interpolation (Interpolation / resampling) is an image processing method, which can increase or decrease the digital image pixel number. .Some digital cameras use to create a pixel interpolation method to produce than the actual pixel multi-sensor images, or create images generated by digital zoom. .In fact, almost all of the image processing software to support one or more interpolation. .Aliasing enlarged image directly reflects the strength of interpolation image processor maturity. .</ P> <P> The following example is a 106 * 40 450% image magnification as the effect of: </ P> <P align=center> </ P> <P> closest to the principle of interpolation (Nearest Neighbor Interpolation .) </ P> <P> closest to the principle of interpolation is the simplest interpolation method, which is the nature of amplification pixels. .New image is the original image pixel color and location of the nearest pixel to create the pixel color. .If the original image enlarged 200%, one pixel will be enlarged into a (2 * 2) 4 and the original pixels of the same color pixels. .Most image browsing and editing software will use this enlarged digital image interpolation method, because it does not change the color of the original image information, and no anti-aliasing effect. .Similarly, in practice this method to enlarge the picture is not appropriate, because the interpolation will increase the visibility of jagged images. .</ P> <P align=center> </ P> <P> bilinear interpolation (Bilinear Interpolation) </ P> <P> in the bilinear interpolation, the new pixel value creation, is the original image .location in its vicinity (2 x -2) 4 are adjacent pixel value calculated by the weighted average. .The average algorithm put jagged effect, created an image with smooth edges, serrated difficult to detect. .</ P> <P align=center> </ P> <P> bi-cubic interpolation (Bicubic interpolation) </ P> <P> bi-cubic interpolation is a more complex interpolation methods, it can create more than double .linear interpolation smoother edges. .The reader is aware of the eyelashes under the part of the figure, in this place, the software created by bi-cubic interpolation of a pixel, and this pixel value is determined by its nearby (4 x 4) were derived from the neighboring pixel values ., and therefore higher precision. .Bicubic interpolation method is usually used in the part of the image processing software, printer drivers and digital cameras, the original image or the original image to zoom in some areas. .Adobe Photoshop CS offers a more user double-cubic interpolation of two different methods: bicubic interpolation bicubic interpolation smoothing and sharpening. .</ P> <P align=center> </ P> <P> bi-cubic interpolation </ P> <P align=center> </ P> <P align=center> (1) bi-cubic interpolation smoothing (2 .) ordinary two-cubic interpolation (3) bi-cubic interpolation sharpening </ P> <P> fractal interpolation (Fractal interpolation) </ P> <P> fractal interpolation is often used in image magnification is .Great situation (such as to produce a substantial print). .It enables enlarged image in terms of shape, edge and color, closer to the original image, and reduce the blurring of photos, better than bicubic interpolation method even better. .The figure on the reader can compare the above picture, you know interpolation fractal of the advantages of: </ P> <P align=center> </ P> <P>, of course, in addition to the four interpolation methods but .There are other interpolation methods. .However, other interpolation methods are not commonly used, but they require more complex and sophisticated image processing (enlarge) technical support. .As non-professionals, we can not have these technologies..

Dynamic Range (Dynamic Range).

The dynamic range of the sensor dynamic range that included the image from the "darkest" to the "brightest" of the range. .Larger dynamic range, can say the level of the more abundant, contained in the more wide color space. .As shown below: the greater the dynamic range of the camera, it can also record the shadow detail and highlight the details of the more abundant. .Note to reader, dynamic range and tonal range (ton <P> sensor dynamic range </ P> <P> dynamic range that included the image from the "most secret" to "the brightest" of the range. Dynamic range greater .beyond the level that the richer the color space is also included in the more widely. as shown below: </ P> <P align=center> </ P> <P> greater dynamic range of the camera, it can also record .The shadow detail and highlight detail richer. Please readers, dynamic range and tonal range (tonal range) is different. </ P> <P> dynamic range images </ P> <P> when we use JPEG format .picture, the camera image processor will be a strong difference between light and dark image information recorded tone curve. In this process, often eliminating the need for the processor as part of RAW data, the shadow detail and highlight detail. RAW format to maintain the digital image .sensor's dynamic range, and allows the user to a suitable dynamic range and tone curve compression tonal range, so that output to display or print the photos came out, appropriate dynamic range for viewing. in the tonal range of topics, we introduce .an extreme example. From this example we can see in the 32-bit floating point images, large dynamic range and tonal range is to be compressed. </ P> <P> pixel size and dynamic range </ P .> <P> see this place, I believe that readers should be clear: the digital camera sensor is composed of hundreds of millions of pixels, these pixels in the sensors absorb photons during the exposure, converted into digital signals, and imaging. .This process took millions as we go outside to collect rainwater buckets. more light sensitive area, the amount of photons collected more natural. the sensor to light, each pixel sensor in accordance with the different amount of collected photons, given they are not continuous .value, converted to digital signals (for details see the front of the AD converter). there is no absorption of photons and the absorption of photons to the full pixel values are "0" and "255", which represents pure black and pure white. The figure .only 16 pixel sensor, the sensor pixels can be rapidly absorbed photons during the exposure. </ P> <P align=center> </ P> <P> Once these pixels loaded, the photon will overflow. Overflow .will lead to information (details) loss to red, for example, high light spill so full of the red pixel values of other nearby pixels have become 255, but in fact they did not reach the true value of 255. In other words, the picture .details of a loss. in the histogram part we have already mentioned some of this will result in the high light information is missing. On the other hand, if we reduce the high light exposure time to prevent overflow, a lot of pixels used to describe the dark environment is not enough time .receiving photon volume, resulting pixel value is 0, so that it will lead to dark parts of the missing information. </ P> <P> Through the above description, we can now understand why the digital SLR will have a greater dynamic range. .The reason is simple: the larger the pixel digital SLR. not too big a pixel is "filled", so described in the dim light environment, the environment pixel pixel in the description "full" before, have more time to absorb .photon, the picture will be more rich detail. </ P> <P> example of the dynamic range </ P> <P align=center> </ P> <P align=center> the dynamic range of the camera and scene dynamic range of basic .match. histogram shows that there is a wealth of photos highlight and shadow detail. </ P> <P align=center> </ P> <P align=center> camera's dynamic range smaller than the dynamic range of the scene. histogram shows photos .missing highlight detail and shadow detail. </ P> <P align=center>.

Digital Zoom (Digital Zoom).

Optical zoom camera by the camera lens in the minimum and maximum focal length to choose between. .And quasi-professional consumer digital camera with digital zoom is often also the following, we had a 500 million pixel digital camera quasi-professional pictures are, for example, talk about the digital zoom. .A, with scenes shot in 31mm B, with a 50mm focal length lens to shoot the scene from the camera 31mm <P> optical zoom in the camera lens are the minimum and maximum focal length to choose between. .And quasi-professional consumer digital camera with digital zoom is often also the following, we had a 500 million pixel digital camera quasi-professional pictures are, for example, talk about the digital zoom. .</ P> <P align=center> </ P> <P align=center> A, scenes shot with the 31mm lens </ P> <P align=center> </ P> <P align=center> B, .with a 50mm lens shooting scenes </ P> <P> change the focal length from 31mm 50mm (50/31 = 1.6X optical zoom), we see pictures of the scene covered smaller. .In Figure B, the red box area is A scene graph. .In the two pictures, the camera will be 500 million pixels of photographic record of the 500 million pixels of information. .</ P> <P align=center> </ P> <P align=center> C, 1.6 times digital zoom, the resolution dropped </ P> <P align=center> </ P> <P align=center> .D, 1.6 times digital zoom The images </ P> <P> 1.6 times digital zoom the image will only be used after the 1,600 x 1,200 pixels of information, and discard the rest of the information (2,560 / 1.6 = 1,600 and 1,920 / 1.6 .= 1,200). .In Figure C, the size of the camera to capture the scene with the map A is the same, but Figure C is only used in 500 million to 200 million pixels pixels! .If the digital camera has a resolution of 1,600 x 1,200 of the shooting options, photographs will be saved as a 200 million pixel image. .So we see that through the digital zoom the map after the D, there are only 200 million pixel resolution, clarity has declined markedly. .In the digital zoom, the camera image processor does not create additional information, so the image quality Figure D Figure B was significantly lower than that. .</ P> <P> in the end whether we should use the digital zoom? .? .</ P> <P> Since the digital zoom through the image quality will be obvious after the drop, then we should also should not use it? .If your goal is to obtain the image information in Figure B, use the 50mm focal length of course is the best choice. .But if your camera is only 31mm (or if you have the optical zoom lever pulled the telephoto end, but you want to zoom even further), you can have the following three options: </ P> <P> <1> .; we recommend the practice of the digital zoom off to the highest pixel camera shooting, shooting and then as you need to repair the computer, to enlarge image. .</ P> <P> <2> If you have a 500 megapixel camera output 200 megapixel image option, put the digital zoom to open, use 1.6 times digital zoom. .1,600 x 1,200 resolution of the photos will be saved to memory card, and photos of this 200 million pixels to record a 200 million pixels of information. .</ P> <P> <3> We do not recommend using the most 1.6 times digital zoom, while the 500 million pixel output. .Because at that time not only takes up more memory card space, and adjust the latter part of output pictures is greatly reduced. .We can imagine: to 200 million pixels of information (Figure C) Zoom into a 500 million pixel images (Figure D), how bad effect. .</ P> <P> Finally, we should keep in mind when using digital zoom point: the digital zoom does not create camera can not capture the details, digital zoom imaging and imaging optical zoom can not be compared. .</ P>.

Image Compression (Compression).

There are two image file compression: lossless and lossy compression. .Lossless compression lossless compression effect similar to WinZip. .In the WinZip compression, if you put a file compressed into a Zip file, unzip and then re-open the original file, you will find the files after extracting the original file and with no difference. .In the process of compression and decompression and image files without any <P> There are two compression: lossless and lossy compression. .</ P> <P> lossless compression </ P> <P> WinZip lossless compression with similar results. .In the WinZip compression, if you put a file compressed into a Zip file, unzip and then re-open the original file, you will find the files after extracting the original file and with no difference. .In the process of compression and decompression, and no information is missing. .TIFF format, digital images will allow users to its lossless compression. .</ P> <P> lossy compression </ P> <P> lossy compression to reduce image size by discarding information (size), as the summary document preparation. .When you need a 10-page document prepared summaries, these summaries may account for only 9 or even one, who did not read the original documents from you to restore the original summary document, because you are in the process in the preparation of summary .has been discarded as part of the original file. .JPEG is a lossy compression image format. .</ P> <P> The following table shows a 500 million pixel images (2,560 x 1,920) the effect of different compression formats. .</ P> image format is usually file size (MB) Notes uncompressed TIFF14.13 channel, 8-bit uncompressed 12-bit RAW7.71 channel 12-bit lossless compressed TIFF6.0 12 RAW4.3 approximate compressed lossless compression .100% Quality JPEG2.3 and uncompressed image is difficult to distinguish between 80% Quality JPEG1.3 can handle 4 "x 6" print size of 60% Quality JPEG0.7 able to cope with network share 20% Quality JPEG0.2 poor quality .<! - Navigation Menu - ".

Color space (Color Spaces).

RGB additive method (Additive RGB Colors) cone cells in the human eye to red, green, blue (RGB) is most sensitive to three colors. .We are perceived by the other colors are three colors obtained by mixing different proportions. .Computer monitors emit red, green, and blue light mix to produce different colors. .For example, red and green mix to produce yellow; <P> RGB additive color (Additive RGB Colors) </ P> <P> cone cells in the human eye to red, green, blue (RGB) is most sensitive to three colors. .We are perceived by the other colors are three colors obtained by mixing different proportions. .Computer monitors emit red, green, and blue light mix to produce different colors. .For example, mixing red and green produce yellow; red, green and blue primary colors mixed produces white. .Look at the chart: </ P> <P align=center> </ P> <P align=center> RGB additive color </ P> <P> CMYk subtractive (Subtractive CMYk Colors) </ P> .<P> a print of their body fell through the reflection of light, indirectly, we can see its color. .For example, a yellow sheet of paper will absorb the white light (natural light) in the blue, red and green part of the reflection, which show yellow. .This approach directly with the display is red and green produce yellow light while the effect is very similar. .Printer through the blue (Cyan), Magenta (Magenta), Yellow (Yellow) ink mixed in different proportions to create other different colors. .CMYk the color combination and subtraction may produce black. .But in fact the printer will use black ink to enhance the effect of black. .Therefore, CMYk final "k" is to represent the black (black). .</ P> <P align=center> </ P> <P align=center> CMYk subtractive </ P> <P> LAB and Adobe RGB (1998) Color </ P> Due to technical constraints, displays and .printer and can not export our naked eyes can see all the colors, the color is LAB color. .Through the following diagram, we can see the horseshoe-shaped distribution of LAB color. .General computer monitors can observe the color is sRGB (add color) color printer output is CMYk (subtractive) color. .CMYk color there are various types, these types of equipment with the output vary. .<P> We can see the picture below, not all colors can be output from the monitor or printer. .Some high-end digital cameras allow users to Adobe RGB (1998) shooting mode, Adobe RGB color range than the sRGB and CMYk large. .Therefore, they are richer color image output. .But we can not forget that most of the displays only support sRGB color. .</ P> <P align=center> </ P ><!-- Navigation Menu - ".

High light spill (Blooming).

Digital camera sensor pixel is responsible for collecting photon and photon by photodiodes put into charge, followed by a series of processing, the formation of the image. We in the "dynamic range" topic has been on the inside, upon receiving the "barrel" photon (bucket) loaded by additional photons into charge will overflow, and the overflow of values the object is not affected,

Digital camera sensor pixel is responsible for collecting photon and photon by photodiodes put into charge, followed by a series of processing, the formation of the image.

We in the "dynamic range" topic has been on the inside, upon receiving the "barrel" photon (bucket) loaded by additional photons into charge will overflow, and the overflow is not an object of value, so the impact will cause the value of photosensitive pixel is insufficient or overexposure. When the charge overflow to the next pixel to pixel in handling next to Photon processes overexposure (for example describes the sky bright pixel is charge overflow leaves or branches on the edge of the darker pixel overexposure), this is the "highlight overflow". Highlight overflow will void the picture loss of detail, but also increases the chance of purple edges appear.

Some of the sensor with the "highlight overflow protection" (anti-blooming gates), absorption, reducing the charge of overflow overflow charge on nearby pixels.

This function can suppress overflow highlights basic unless photos very strong light-dark contrast or due to anthropogenic causes serious too exposed photos.

Aliasing (Aliasing)

Aliasing (Aliasing) refers to the image in a non-linear (slash) lines appear jagged, such as round the edges. Why appear jagged?, in fact, the reason is simple: because the composition of the image pixels are square. Let us look at the chart below: terminology properly view (1 x) magnification view (4 ×) annotations confuse phenomenon sawtooth clearly visible

Aliasing (Aliasing) refers to the image in a non-linear (slash) lines appear jagged, such as round the edges.

Why appear jagged?, in fact, the reason is simple: because the composition of the image pixels are square. Let us look at the chart below: terminology properly view (1 x) magnification view (4 ×) comment aliasing anti-aliasing is clearly visible, enlarged sawtooth particularly obvious-aliasing not so obvious that the line looks smoother

Anti-aliasing (Anti-aliasing)

Aliasing edges by average pixel method so that the image's edge looks smoother.

In the example above, some blue pixel insert into yellow edge pixels, at the same time, some yellow pixel insert into blue edge pixels. This transfer allows image circle from yellow to blue background process is gradual and smooth lines and more. Most image editing software with "aliasing" option, this option can be used for the type of font, drawing lines, shapes, wide selection and so on. In addition, all digital cameras have built-in "aliasing" feature that enables the photos look smoother.

Professional analysis; from imaging on optical zoom and digital zoom

In our contacts with many models of digital cameras appear optical zoom and digital zoom concept. For just getting started with digital cameras, and prepared to make the choice of the consumer, often only see both the ability to zoom in on distant objects, and not specific to tell the real difference between the two. This often leads to a specific purchase choice mistakes. In fact, optical

In our contacts with many models of digital cameras appear optical zoom and digital zoom concept.

For just getting started with digital cameras, and prepared to make the choice of the consumer, often only see both the ability to zoom in on distant objects, and not specific to tell the real difference between the two. This often leads to a specific purchase choice mistakes. In fact, the optical zoom is digital camera lens of a very important parameter, and the digital zoom the existence of differences in nature.

The difference is not only reflected in their works, in the final image, they will also have significant differences.

Only from imaging quality, optical zoom ratio digital zoom elite. But digital zoom because of low cost, widely also in consumer-level digital cameras equipped. Moreover, with the image processing technologies of enhancement, Digital Zoom effect has also improved, for example Sony SmartZoom digital zoom technology, is a more practical digital zoom technology.

In the face a large number of technical information, consumers seems more difficult, but in the optical zoom and digital zoom the how to make a choice between? here is difference, practical and specific problems such as choosing to do some simple statements, hoping to give everybody the purchase offer some advice.

Optical zoom and digital zoom for each principle

Optical zoom

To understand the principle of optical zoom, first of all let's see what lens imaging process.

In our junior high school physics class, the teacher will give us a magnifier Imaging tests, burning candles through magnifying glass will whiteboard clearly came out at the same time as the projection magnifying glass in the before and after the move, burning candles at the Whiteboard image size will change. This is both a camera and imaging of principle, the principle of optical zoom. The camera's optical zoom is by changing the lens focus position, in order to change the angle of the light entering the lens, so that the same distance of the camera object in the PC component becomes larger, or more distant objects can have to focus more clearly on the PC components.

Top camera imaging, simple plan, the optical zoom is by moving the lens the internal lens to change focus position, change the length of the lens focal length, and change the size of the camera lens to achieve the image zoom in and zoom out.

The previous figure, a red triangle long right-angled edges is the camera's focal length. When you change the location of the focus, the focus will change. For example, set the focus to move in the opposite direction of imaging surface, the focal length will get longer, the perspective will be smaller. In this way, the angle range of scenery in Imaging surface becomes even greater. This is the principle of optical zoom.

We always contact digital optical zoom focal length, it actually is on the focal length of length in the figure.

Such as the Canon A95 's 3 x optical zoom lens, focal length 7.8-23.4mm, referring to the focal length can change, in fact that is being taken to enlarge the scope of the object. While the equivalent focal length above jiaochang is formatted as a traditional 35mm camera focal length, and thereby become more intuitive, the problem is not in the scope of our discussions.

Digital Zoom

Digital zoom in principle to understand some of the more complex.

Now the mainstream technology, digital zoom is to use the image processor PC components in a region of the photographic unit of image information for separate zoom. However, the mere fact of zooming and image processing software for local amplification is exactly the same, without any value. Now, many manufacturers of digital cameras internal already contains image routing software, it can image zoom, detail loss at each pixel, peripheral characteristics analysis of pixels, and analysis of data obtained from the increase in the pixels surrounding pixels, in fact is the so-called "interpolation" Imaging. This to some extent reduces local amplification on the image quality of the image, but in fact, such a reduction is often very limited.

We are digital camera imaging structure simplification can get on the map.

In digital zoom, photo objects through the lens in the PC component projection image size does not change. Simply, the camera's internal software through the PC component of the central part, and the pixel for interception with built-in software to zoom in and interpolation, so as to achieve the effect of the image to enlarge. This process is that we often see in the digital camera with digital zoom.

Shutter speed (Shutterspeed)

The shutter speed determines the film or sensor exposure time. Camera lenses and film by controlling (sensor) mechanical shutter "an open a hop" two actions to control the shutter speed, thus controlling the exposure time. For example, the shutter speed to 1/125s means the camera sensor (film) exposure of 1/125 sec. Electronic shutter and similar mechanical shutter, not

The shutter speed determines the film or sensor exposure time.

Camera lenses and film by controlling (sensor) mechanical shutter "an open a hop" two actions to control the shutter speed, thus controlling the exposure time. For example, the shutter speed to 1/125s means the camera sensor (film) exposure of 1/125 sec. Electronic shutter and similar mechanical shutter, but it is by controlling the photodiode sensor to control the shutter speed. Some digital camera shutter is a mechanical shutter and electronic shutter.

Shutter speed in seconds to score form, usually faster shutter speed was at the level of the slow shutter speed at 1/2 that the exposure time by half.

For example, 1/2s, 1/4s, 1/8s, 1/1/15s, 30s, 1/60s, 1/125s, 1/250s, 1/500s, 1/1000s, 1/2000s, 1/4000s, 1/8000s, etc. However, the slow shutter speed is usually expressed in seconds, for example, 8s, 1s, 2s, 4s.

Shooting environment determines the most appropriate shutter speed.

But here there is a small Tip: use the "1/focal length" seconds more shutter speed can effectively prevent camera shake and blur. When the shutter speed value lower than this, please use a tripod or with optical stabilizer lens or camera. If you want to use the camera "freezing" of an action (for example in sports photography), shutter speed of at least 1/250s or even more. However, not all "moves" filming needs high speed shutter. If the user wants to shoot a movement of the car, you can shoot through the camera follow (camera movement and the same vehicle moving relative velocity), the movement of the car remains in the viewfinder. This not only allows the user to use a slower shutter speed shooting, and able to take out the background of dynamic blur effect, increase screen dynamic.

This picture to 1/500s shutter speed shooting, solidifying the spray dynamic posture.

To 1/125s shutter speed shooting, causing the background to follow dynamic fuzzy, speed sense.

Associate professional-level and professional-grade digital cameras typically provide a shutter priority mode that allows the user to maintain exposure constant change shutter speed.

Metering (Metering)

Digital camera metering system in accordance with the shooting environment to different metering mode (following the specific analysis) measurement of luminance, and calculates an optimal exposure value, make photos accurate exposure. AE is all digital cameras come with standard exposure program, as long as you choose good metering mode, turn the lens alignment is a singularly objects, gently press the shutter, an exposure accurate picture

Digital camera metering system in accordance with the shooting environment to different metering mode (following the specific analysis) measurement of luminance, and calculates an optimal exposure value, make photos accurate exposure.

AE is all digital cameras come with standard exposure program, as long as you choose good metering mode, turn the lens alignment is a singularly objects, gently press the shutter, an exposure accurate picture immediately rendered (in most cases).

Metering mode means the metering system according to what information in your environment to what law photometric calculation reasonable exposure value.

Metering mode with the camera model and brand, but most can be divided into the following 3 types:

Matrix metering or evaluation of metering

This is a comprehensive strongest metering mode, basic in any environment, figure out the most accurate exposure.

The essence of the matrix metering is to take the environment into a multiple metering zones of matrix, the system for each region independently metering, and then to a set of algorithms calculate the best exposure value. Therefore, the camera metering system of algorithms is the key to determining the exposure value, a digital camera manufacturer generally does not disclose the algorithms for details. But we know that this set of algorithms are usually based on the shooting environment and some typical scenarios for comparison to calculate a reasonable exposure value.

Central-weighted average metering

This is the most common digital camera metering mode, almost all digital cameras come with this type of metering mode, some no metering mode selection of digital camera's default metering mode is the central focus of average metering mode.

This metering mode the whole screen, the average measuring light, but with a particular focus on the Center area. The central focus of average metering is widely applied in portrait photography.

Point (partial) metering

Point metering allows users to screen center absorbed object focus metering (some cameras are also available on the selected AF point).

At the point of metering mode, move the camera only on a small area metering, ignore the rest of the screen. This metering mode is typically used for shooting silhouettes, macro and shoot the Moon, and so on.