[Xperia Z1 General] jos_031:
Xperia Z1 camera:

Exposure is basically the AMOUNT OF LIGHT (controlled by the aperture) that is captured over a SPECIFIC AMOUNT OF TIME (controlled by the shutter speed).

A HIGH aperture number (fstop) = LESS light being recorded on your digital sensor while a LOW aperture number = MORE light being recorded on your digital sensor. apertures are called fstops.

Xperia z1 have Fstop of 2.0 which is really good and low. Sony Cybershot DSC-RX100, Panasonic Lumix DMC-LX7. Samsung EX2F, Canon PowerShot G15, Leica D-Lux 6, Nikon Coolpix P330, Olympus XZ-2 iHS all have f2.0

Shutter speed: it is the amount of time your shutter stays open when you click the button

The longer your shutter stays open the more motion it will have time to record. The shorter the time your shutter remains open, the more motion it will freeze. But at low light you need more exposure

ISO rating along with the shutter speed and aperture setting are the three elements that determine the final exposure of the photographic image.

The ISO rating, which ranges in value from 25 to 6400 (or beyond), indicates the specific light sensitivity. The lower the number, the less sensitive to light the film stock or image sensor is. Conversely, a higher number indicates a higher sensitivity to light, thereby allowing that film or image sensor to work better in low light conditions.

the lower ISO rating also meant that the photosensitive grains of salt on the film acetate were very fine, thus producing a smoother, cleaner image. A higher ISO had larger, jagged grains of salt, thus producing “rougher” or grainier images.

Lower ISO ratings produce color-accurate, smooth and aesthetically appealing images… and this requires ideal lighting conditions. However, there are some subjects that you want to photograph in low light conditions. Or, you may want to stop fast-moving objects. In both situations, you need higher ISOs to capture those images with an acceptable exposure.with the higher ISOs, you can use faster shutter speeds to eliminate motion blur and/or camera shake. In the event that you want to use motion blur creatively, then decreasing the ISO is simple, and you can then decrease the shutter speed to achieve the desired motion blur and still have smooth, noise-less images.

The size of the digital camera’s image sensor dictates what ISO setting provides the least amount of digital noise. One must understand that image sensor size is not the same thing as pixel count. Image sensor size is the actual physical dimensions of the sensor, for most of the history of digital photography the image sensor has been smaller than a 35mm film frame. On point and shoot cameras, the sensor was quite small, and on most DSLR cameras, the image sensor has been the size of APC film (23x15mm). Smaller image sensors produce much more digital noise at higher ISOs (like 800) mainly because the high pixel count means that more pixels are being packed into a smaller area, thus producing more grain at all but the lowest ISO.

Sony xperia Z1 has sensor size of 1/2.3. Most compact digital cameras used small 1/2.3" sensors. Such cameras include Canon Powershot SX230 IS, Fuji Finepix Z90 and Nikon Coolpix S9100.

Whenever you shoot in low light or use a long lens, or if you simply aren't holding a camera steady, you risk introducing camera shake into your images. This manifests itself as a blurring of details, and unlike other image quality issues it's not something that can be fixed in post-processing.

The three main image stabilisation systems on offer:

Manufacturers have different names for lens-based stabilisation, but they all largely work in the same way.

ISO based

All but the cheapest compacts offer image stabilisation, and the easiest solution from the manufacturer's point of view is one based on sensitivity. This adds nothing to the manufacturing of a camera as it's simply the ISO which needs to be adjusted, easily handled by the camera's firmware.

As this is the most basic form of image stabilisation, and as other types are preferable, manufacturers often call it 'digital' image stabilisation in press releases and throughout specification lists.

With this type of image stabilisation, the camera looks at the focal length and shutter speed being used, and decides whether the two will create a sharp enough image. If it deems them to be inadequate the camera's sensitivity will be raised, which in turn increases the shutter speed, but the resulting signal will need to be amplified to a greater extent.

So, a camera could choose to raise an image that would be otherwise captured at 1/20sec to 1/80sec, but it would need to raise the sensitivity twofold. So, from ISO 100 this would rise to ISO 400, from ISO 200 to ISO 800 and so on.

The image is still captured sharply as a more appropriate shutter speed has been used, but this process gives rise to noise which is typical with images captured at higher sensitivities. For this reason other systems are preferable in more expensive cameras and lenses. In many compacts, this method is often complemented by sensor-based stabilisation.

Sensor based

Sensor-based stabilisation also uses information such as focal length and shutter speed on which to base its calculations, but instead of adjusting the sensitivity the camera physically moves the sensor.

The sensor will typically be mounted on a platform, which will move to compensate for any movement when the camera senses it is necessary.

Minolta first introduced the feature in its DiMAGE A1 camera back in 2003, and, after merging with Konica, incorporated it into the 7D DSLR.

Sony continued the feature when it took over Konica Minolta's imaging business, and was soon joined by Pentax, Olympus and others. All three companies continue to use the system today, and it has since been adopted by other manufacturers for their own hybrid systems and compacts.

In the case of DSLRs and hybrids, this type of image stabilisation brings the significant advantage of allowing lenses to be made smaller, lighter and cheaper (as they do not need to incorporate any form of image stabilisation themselves), and is effective with virtually any mounted lens. This is particularly handy in the case of older lenses which predate image stabilisation technology, although it may be necessary to first input the focal length of the lens into the camera, depending on the lens, camera and the nature of communication between the two.

Lens based

Lens-based image stabilisation came just before digital cameras were made accessible, but the two have more or less evolved over a similar space of time.

Today, the technology is found in a range of optics manufactured by Canon and Nikon (particularly those targeted towards the professional), as well throughout the ranges from independent lens manufacturers Sigma and Tamron. Panasonic also uses the system in its lenses designed for the Micro Four Thirds system, as well as those found in its Lumix range of compacts.

Lens-based stabilisation systems typically work by shifting a lens group towards the rear of the lens on a plane perpendicular to the optical axis.

This is done with the help of two gyro sensors inside the lens, one for yaw and one for pitch. These notice the angle and speed of any movement, and this information is fed to a microprocessor which computes the necessary adjustments needed to be made by the lens group. By doing so, the light's angle of refraction is changed so that it hits the sensor in the right place.

Manufacturers of these systems claim that this type of stabilisation is the most effective as it can be tailored specifically to the objective in which it us used. And, as stabilisation takes place in the lens, the photographer is able to view the effect through the viewfinder.

Typically this activates once the shutter release has been half-depressed, although it is possible on different camera/lens combinations to set when the stabilisation begins, such as only at the moment of capture, for example. This has the additional benefit of conserving power, as, left on all the time, lens-based image stabilisation systems can eat up battery power fairly quickly.

One recent development in this area is Canon's Hybrid IS system, which offers two types of correction.

The first is via an angular velocity sensor which notices rotational shake, which is found in existing image-stabilised lenses.

Canon 100mmThe second - and what makes the Hybrid IS system different - is a separate sensor for noticing camera shift (linear) movements, such as when a camera moves up, down, left or right while remaining parallel to the subject. Canon claims that by incorporating both sensors camera shake is better corrected.

I feel low noise is more important than full zoom blur..

the focal length describes the distance in millimetres between the lens and the image it forms on the sensor (or film) when it is sharply focused at infinity - the farthest possible distance.

When a ray of light passes from a less dense to a more dense medium (such as from air to glass) it slows down. If it strikes the glass surface at an angle, it is also bent a little, and this is called refraction. When it passes back into air, it speeds up again, and is again refracted if the surface is at an angle.

Thus a curved piece of glass will focus a parallel beam of light (arriving perpendicular to the lens, that is along its axis) to a point. The interesting thing happens when the light rays are parallel to each other but not parallel to the axis through the centre of the lens. This same lens will also focus these, but to a point above, below, or beside the focal point for rays along the axis, and all these points of focus of parallel rays will form a plane, called the focal plane of the lens. So, you put the sensor at this focal plane, and you've now used the lens to concentrate the light on the sensor.

As the focal length and magnification of a lens increases, the image appears more compressed, resulting in less visual distinction and separation between the foreground, middle ground, and background.

With shorter focal lengths and wider angles of view than standard lenses, wideangle lenses are employed by landscape and reportage specialists. Remember you'll need a shorter focal length on many DSLRs to get the equivalent field of view if you don't have a full-frame sensor. There's a plethora of wideangle lenses available, from 8mm ‘fisheye' lenses to 28mm lenses. Wide zooms are increasingly popular and effective.

Sony xperia Z1 uses 27mm wide angle lens... this good for parties if you need background and sceneries.

Personally i feel the problem with all sony mobile phone camera is their digital image stabilisation process. they are kicking in more ISO to make it look grainy. i cannot confirm it since i cannot get the picture sample during various stages of processing. but this is a very possible candidate. Since post processing will not induce so much issue.. even with not so professional algorithms i made using wavelength, cosine transforms and other denoising and sharpening algorithms. I can make better results.

Camera Sensor

There are 2 types of sensors CMOS and CCD

In a CCD device, the charge is actually transported across the chip and read at one corner of the array. An analog-to-digital converter turns each pixel's value into a digital value. In most CMOS devices, there are several transistors at each pixel that amplify and move the charge using more traditional wires. The CMOS approach is more flexible because each pixel can be read individually.

CCDs use a special manufacturing process to create the ability to transport charge across the chip without distortion. This process leads to very high-quality sensors in terms of fidelity and light sensitivity. CMOS chips, on the other hand, use traditional manufacturing processes to create the chip -- the same processes used to make most microprocessors . Because of the manufacturing differences, there have been some noticeable differences between CCD and CMOS sensors.

CCD sensors, as mentioned above, create high-quality, low-noise images. CMOS sensors, traditionally, are more susceptible to noise.

Because each pixel on a CMOS sensor has several transistors located next to it, the light sensitivity of a CMOS chip tends to be lower. Many of the photons hitting the chip hit the transistors instead of the photodiode.

CMOS traditionally consumes little power. Implementing a sensor in CMOS yields a low-power sensor.

CCDs use a process that consumes lots of power. CCDs consume as much as 100 times more power than an equivalent CMOS sensor.

CMOS chips can be fabricated on just about any standard silicon production line, so they tend to be extremely inexpensive compared to CCD sensors.

CCD sensors have been mass produced for a longer period of time, so they are more mature. They tend to have higher quality and more pixels.

CMOS sensors produce less noise at high ISOs, but CCD sensors tend to be sharper given a consistent scene.

These factors also contribute to the clarity of the clarity of the image and more noise in sony cameras.

front illuminated sensor

Front-illuminated digital camera sensor consists of a matrix of individual picture elements where each element is constructed with a lens at the front, wiring in the middle, and photodetectors at the back. This traditional orientation of the sensor places the active matrix on its front surface and simplifies manufacturing. The matrix and its wiring, however, reflect some of the light, and thus the photocathode layer can only receive the remainder of the incoming light; the reflection reduces the signal that is available to be captured

Backlit CMOS

A backlit is different from a regular CMOS sensor, in that all the wiring and circuitry that's used to carry the electronic signals from each photosite or pixel is located at the back of the sensor instead of the front.

The photosites on most sensors consist of a micro lens, then some wiring, and behind that the photosites that record the light falling on the sensor. By removing the wiring and circuitry from the area between the lens and the photosite, far more light is able to reach the photosites, and this in turn means the image being captured needs far less amplification.

A back-illuminated structure minimizes the degradation of sensitivity to optical angle response, while also increasing the amount of light that enters each pixel due to the lack of obstacles such as metal wiring and transistors that have been moved to the reverse of the silicon substrate.

However, compared to conventional front-illuminated structures, back-illuminated structures commonly causes problems such as noise, dark current, defective pixels and color mixture that lead to image degradation and also cause a decrease in the signal-to-noise ratio.

This also further degrades the image quality.

Exmor-R

Sony's branding of this backlit sensor is called Exmor sensor..

To overcome the disadvantages of backlit Sony has developed a unique photo-diode structure and on-chip lens optimized for back-illuminated structures, that achieves a higher sensitivity of 6dB and a lower random noise of 2dB without light by reducing noise, dark current(The relatively small electric current that flows through a photosensitive device when no photons are entering the device). and defect pixels compared to the conventional front-illuminated structure. Additionally, Sony's advanced technologies such as high-precision alignment have addressed any color mixture problems. Also it uses unique "Column-Parallel A/D Conversion Technique" and dual noise reduction.. but based on the samples i have tested in mobile sony was not able to reduce noise up to 2db and dark current is not fully filtered out. This can be seen in Xperia Arc. the first phone with this sensor. but still there was supporting circuitry. adjacent to the pixel section.

Exmor- RS

The “Exmor RS” is a CMOS image sensor that adopts a unique ‘stacked structure.’ This structure layers the pixel section, containing formations of back-illuminated pixels over the chip affixed with mounted circuits for signal processing, in place of conventional supporting substrates used for back-illuminated CMOS image sensors.this further reduces light reflection.

Xperia Z1 display:

Triluminous: all LCD display cant emit light by themselves. they need a backlight to produce the light. All displays have white backlight . White light contains all colors of visible color. LCD contains 3 Filters per pixels called subpixel which allows only one light to pass through them. one for red, one for blue and one for green. these are called primary colors. and using the combinations of these colors any color can be made. but in normal screen it passess colors other than these by passing similar colors. for eg orange for red. this produces less accurate colors. Sony changed this white light into triluminous technology. Here they use quantum dots behind each subpixel. these have different properties.the one behind red absorbs blue light, gets excited and transmits red light. green one emits green.. so the backlight used is blue. hence the colors produced are more accurate.

human can see colors between wavelengths of 400 to 700 nm. the following figure represents CIE diagram of human eye

In order to check the color reproduction of the display. pass pure red, green and blue light. mark the point in CIE diagram which gives same color. draw a triangle connecting these points. you will get all the color that display can produce. normally all displays produce sRGB color space.Which is represented in fig

If you see the figures superamoled has the widest gamut.

If you see for triluminous for mobile it is seen that it cant produce the same gamut as seen on TV. it is just a little wider. not as much as sony claims

It is better than all phone except amoled screen

X-Reality:

Hue, along with saturation and brightness make up the three distinct attributes of color.

hue

refers to a pure color—one without added white or black. Hue refers to a specific tone of colour. It is not another name for colour as colour can have saturation and brightness as well as a hue.

Saturation

refers to the purity, or intensity of a colour. It is the intensity of a hue from grey. At maximum saturation a colour would contain no grey at all. At minimum saturation, a colour would contain mostly grey. Pink may be thought of as having the same hue as red but being less saturated. A fully saturated color is one with no mixture of white. We increase the separation between colors to enhance saturation. As a result, an increase in saturation results in an increase in contrast, brightness, and sharpness. A change in saturation normally has a more noticeable effect on vibrant colors and less on dull colors or colors that are almost neutral.

Brightness

: refers to how much white, or black, is contained within a colour.

Contrast

: is defined as the separation between the darkest and brightest areas of the image. Increase contrast and you increase the separation between dark and bright, making shadows darker and highlights brighter. Decrease contrast and you bring the shadows up and the highlights down to make them closer to one another. Adding contrast usually adds "pop" and makes an image look more vibrant while decreasing contrast can make an image look duller.

Gamma Adjustment

: nonlinear adjustment to the distribution of midtones in the image. What this means is that you can adjust the middle tones of the image without changing the darkness of the shadows or the lightness of the highlights.

Sharpness

:Sharpness can be defined as edge contrast, that is, the contrast along edges in a photo. When we increase sharpness, we increase the contrast only along/near edges in the photo while leaving smooth areas of the image alone.

Image noise

: Reducing this noise can greatly enhance your final image or print. The problem is that most techniques to reduce or remove noise always end up softening the image as well. Some softening may be acceptable for images consisting primarily of smooth water or skies, but foliage in landscapes can suffer with even conservative attempts to reduce noise. There are various techniques to achieve this.

Color Temperature

is a measurement in Degrees Kelvin that indicates the hue of a specific type of light source. You can use a Color Temperature (as shown in the chart below) to suggest realistic colors for the lights.

During decoding of an image or a single frame in the video. we divide image into 8x8 blocks and apply certain algorithm. After this they analyses these frame to understand the type of content in the image after this they change saturation, brightness, contrast, gamma, enhance the brightness and reduces the noise. this continues till the entire frame is processed. After this the ambient light sensor calculates the type of room in which we are seeing the video and applies a filter. For different scenarios we get different values of the parameters used. this is a dynamic proprietary algorithm. If we put standard color space image to check this, we always get the same result. as the content is not changing. hence it is not possible to decode the algorithm used easily. Battery consumption will be more during this mode due to increased processing.

Panel Technology

Thin Film Transistor

Liquid crystal displays, which are used in calculators and devices with similarly simple displays, have direct-driven image elements; and therefore, a voltage can be easily applied across just one segment of these types of displays without interfering with other segments of their displays. That would be impractical for a large display because it would have a large number of (colour) picture elements (pixels) and thus, it would require millions of connections, both top and bottom for each one of the three colors (red, green and blue) of every pixel. To avoid that issue, the pixels are addressed in rows and columns, reducing the connection count from millions down to thousands. The column and row wires attach to transistor switches, one for each pixel. The one-way current passing characteristic of the transistor prevents the charge that is being applied to each pixel from being drained between refreshes to a display's image. Each pixel is a small capacitor with a layer of insulating liquid crystal sandwiched between transparent conductive ITO layers. This type of arrangement if used the display is called TFT.. all mobile phone displays use TFT active matrix.

Low-temperature polycrystalline silicon (LTPS )

The circuit layout process of a TFT-LCD is very similar to that of semiconductor products. However, rather than fabricating the transistors from silicon, that is formed into a crystalline silicon wafer, they are made from a thin film of amorphous silicon that is deposited on a glass panel.

For DPI above 200 the use of amorphous silicon is not possible hence it is replace by Polycrystalline silicon. The “low temperature” part is important because it means this process can create screens using low temperatures, allowing low-cost substances such as plastics to be used as the backing material on which the display panel is infused or created. As a result, it also means you can create more flexible display panels. Hence LTPS is a description of a manufacturing process, not a display technology.

It is AMVA Panel.. did tests will show my findings,,,

(To be continued)

I have ordered a xperia Z1 for myself.I love it and will use it for one year. only thing i want is better contrast on screen.. rest are really good... the phone i reviewed is not mine..OIS is not that much of an issue. A thing sony could add is support for changing ISO manually in superior Auto...

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