How to choose a digital SLR
Digital SLRs belong to the top class of cameras. The main advantages include interchangeable lenses and manual settings, allowing you to achieve high-quality photographs. SLRs can also be upgraded using a wide range of optional accessories. They use an optical viewfinder, which reflects the image in the lens using a system of mirrors. The photographed image can thus be seen in the viewfinder exactly as it will be captured by the sensor.
Advantages and disadvantages
Frequently asked questions when choosing a digital SLR
Why should I choose a digital SLR?
There are many reasons to choose a digital SLR over another type of camera. Firstly, digital SLRs remain the best cameras in terms of image quality and the obvious choice not only for professionals but also keen amateurs. Digital SLRs come equipped with high-quality sensors and offer many options for controlling the exposure and focus. This means they require a creative approach and optimal settings in a particular situation.
In addition to high image quality, DSLRs are very ergonomic, and their optical viewfinder can capture images in RAW format. DSLRs allow you to use interchangeable lenses and a wide range of other accessories, giving you more options and control than any other type of camera.
How do digital SLRs work?
Digital SLRs use a folded mirror positioned in front of the sensor chip (mostly CMOS or CCD). This mirror reflects the light that passes through the lens directly into the optical viewfinder. This means you actually see in the viewfinder the image exactly as it will be captured in the final photograph. When you press the shutter button, the mirror tilts and the light passes through to the sensor chip. Modern digital cameras are also equipped with Live View function, which allows you to use the LCD display as a larger viewfinder.
Are digital SLRs suitable for beginners?
While it's true that digital SLRs are more difficult to operate, they are still suitable for beginners with a keen and active interest in photography. It is possible for beginners to acquaint themselves with the various manual settings while using the camera. This way you will gain first-hand experience of how the different settings effect the resulting photos, making you a more proficient photographer along the way.
You can either choose a camera body without a lens or an inexpensive kit with a lens. The most popular digital SLR brands are Canon and Nikon.
What is included in the price of an SLR?
You can buy SLRs as a kit including a lens or a body and lens separately. The wide range of accessories available for SLRs, such as tripods, flashes, camera bags and memory card readers, can add to the overall price.
What's important when choosing a digital camera?
Focal length
The focal length of a lens indicates its angle of view and can be divided into two categories: fixed focus lenses and zoom lenses.
Lens types:
Fish Eye (8-14 mm) - for widescreen pictures. Images feature the characteristic hemispherical distortion.
Super wide-angle (15-24) - suitable for landscape photography, interiors and architecture.
Widescreen (25-34 mm) - suitable for indoor and landscape photographs as well as photo reportage.
The perspective of the human eye (50 mm) - corresponds to the viewing angle of the human eye. Suitable for reportage and portrait photography.
Medium lenses (35-100 mm) - perspective close to that of the human eye. Used especially in everyday situations and portrait photography.
Telephoto (100-300 mm) - suitable for portrait, reportage, landscape and sports photography.
Super telephoto (over 300 mm) - used for shooting wildlife and sports.
Aperture
Aperture refers to the opening of a lens's diaphragm through which light passes. The bigger the aperture, the more light the lens is able to let through, which in turn effects the exposure time. Aperture also plays a crucial part in determining the depth of field, or the range of distance in an image that appears sharp. Aperture is measured in so-called f-numbers or f-stops.
- F / 1.8 and below is suitable for portrait lenses, for which a shallow depth of field is important. Such low apertures are possible with some fixed lenses.
- An aperture of about f / 2.8 is achievable with a better lens with varying focal lengths. It can be used in photojournalism and sports photography.
- High f-numbers (eg. F / 16) are used in landscape and architecture photography.
Stabilisation
Some lenses feature optical image stabilisation, which can minimise blur caused by camera shake. Image stabilisation is especially important for reportage and portrait photography.
Focus
Fast and accurate focussing is required when shooting fast motion scenes, typically in sport. The focus mechanism is powered either by a standard motor housed within the body of a digital SLR, or an internal ultrasonic motor, which is both faster and quieter.
Durable body
Digital SLRs feature excellent build quality. More expensive models are even resistant to dust and water.
SLR kits with lenses
Digital SLRs can be purchased individually or in a set with one or two lenses.
Glossary - SLR
CMOS chip
CMOS chips are widely used in digital cameras. Despite low production costs, they offer lower power consumption and faster data transfer than CCD chips. As a result, they are used mainly for digital SLR cameras to help in continuous shooting with faster data transfer. CMOS sensors are able to transmit data from each point separately, while CCD sensors work in rows and columns. CMOS sensors are sometimes abbreviated as APS (Active-Pixel Sensor).
Characteristics of CMOS sensors
Lower energy consumption
Faster data processing
Lower production costs
Both types of sensor chip are suitable for everyday photography.
ISO sensitivity
ISO sensitivity expresses the camera's ability to capture light. To prevent unwanted noise and image blur, higher sensitivity is desirable, especially in low light conditions.
ISO sensitivity can be set individually for each image. The higher the ISO value, the more sensitive the sensor is, and the higher the levels of image noise. Each increasing ISO number is given as twice the value of the previous number, e.g. 100, 200, 400, 800 and 1600. If your camera is set at ISO 400, the image will need half as much light as at ISO 200. At the same time, exposure time will be halved, thereby mitigating potential blur and noise.
RAW
RAW is a high-quality lossless image format that is supported by professional and semi-professional cameras. This format can be used in special editing software to edit sharpness, saturation and contrast without a reduction in the resulting image quality.
Benefits of RAW
- Maximum quality
- The possibility of editing images without affecting their quality
Disadvantages of RAW
- File size
- Slower writing to memory cards
Chip size
The most frequently used sensor chip types in digital SLRs are the APS-C, the dimensions of which are slightly different depending on the manufacturer, and Full Frame chips.