[Xperia Z1 Q&A, Help & Troubleshooting] jos_031:
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

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.

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.

Now i guess everyone got importance of OIS feature..

And i tried the camera of xperia Z1.. the picture was blurry at full zoom. but noise was absent..I feel low noise is more important than full zoom blur...because the photo is excellent for normal usage