An evolution of the DxO Optics Pro software which adds local adjustments – the ability to modify selected areas of a photo only – to DxO Optics Pro, amongst other enhancements. DxO PhotoLab is a standalone program for Mac or PC and its speciality is high-quality raw file processing and automatic lens corrections and optimisation. It comes in a lower cost Essentials and more expensive Elite version.
An extreme telephoto lens with an effective focal length of 400mm or longer and most commonly used by sports, wildlife and press photographers. These lenses are big, heavy and expensive but provide high levels of magnification not possible with ordinary lenses. Some consumer-orientated ‘bridge’ and ‘travel’ cameras have very long zoom ranges that fit into this category, though the small size of the sensor and limited optical quality of the lenses stops them being taken seriously alongside professional cameras.
STM stands for stepper motor lenses, a new type of autofocus motor used by Canon in some of its lenses. Stepper motors offer fast, precise and quiet focus adjustments, so these lenses are well suited both to regular stills photography and to video, where autofocus noise can be picked up very easily by the camera’s internal microphone. Canon’s STM lenses work very effectively with cameras using Canon’s Dual Pixel CMOS AF autofocus system.
See also: Autofocus basics
SLT cameras are made by Sony as a kind of hybrid of the regular digital SLR design and the always-on live view of a mirrorless camera. They do have a mirror in the body, but it doesn’t flip up and down when you fire the shutter. Instead, it has a translucent surface so that the image can pass straight through to the sensor on the back of the camera.
The point of this design is that the fixed mirror can reflect light back on to the camera’s fast phase-detection autofocus sensor even while the image is being composed using a live view image on the rear screen or in the electronic viewfinder.
The downside is that you get all the bulk of a DSLR without the clarity of an optical viewfinder. Sony still makes its SLT models but with improvements in sensor-based hybrid autofocus technology, most expect it will soon transfer all its efforts to its mirrorless models.
As the name suggests, stepping motors move in small, incremental steps. They are simple, reliable and offer a good deal of control and precision. They’re now being used by Canon (STM lenses) and Nikon (AF-P lenses) in a number of consumer-orientated lenses, where they offer fast, quiet and smooth autofocus.