Group (lenses)

Camera lenses used complex configurations of different optical elements, often cemented or fixed together in ‘groups’. Lens groups may be designed to counteract common optical aberrations and you may have autofocus ‘groups’ and zoom groups. Lens elements and groups often move relative to each other in complex ways as the focus and zoom settings are changed.

See also: Lens explained

STM (Canon)

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

Lenses explained

The lens is a fundamental part of any camera. It’s what creates the image on the camera sensor (or film). Some cameras have a fixed, non-removable lens while others offer interchangeable lenses. Your choice of lens has a major impact on the appearance of your pictures, including the lens’s focal length (angle of view) and its aperture setting (which you may or may not be able to adjust). At a simple level the lens is just the thing on the front of the camera, but on a more advanced level lenses open up a whole world of photographic choices, buying decisions and technical comparisons.

Here’s a selection of further lens-related topics

Elements (lenses)

Camera lenses are made up of not just one single lens but many different lens ‘elements’, sometimes cemented or fixed together in ‘groups’. A comparatively simple prime (non zoom) lens may have 6-7 elements while a complex zoom lens might have 17 or more. The different lens elements are needed to compensate for a variety of common lens aberrations and offer autofocus and zoom capabilities.

Pentax K-1 Silver edition announced

Pentax K-1 Silver edition

Pentax K-1 Silver edition

Pentax has announced a limited run of Silver edition K-1 DSLRs.The new camera also includes the latest Pentax K-1 firmware, version 1.4.1. Apart from that, the new model is technically identical to the regular Pentax K-1, the company’s full-frame DSLR.

Highlights include a 36.4-megapixel sensor, an unusual scissor-action tilting rear screen and an in-body anti-shake system that works with any lens. The sensor shift mechanism is used to provide other innovative features, including an anti-aliasing simulation mode to avoid moiré with subjects containing fine patterns, and a Pixel Shift Resolution mode for increased colour resolution with tripod-mounted shots of static subjects. The mechanism also allows an automatic levelling mode and an AstroTracer mode which can keep star fields stationary in the sky during long exposures. The K-1 also has GPS built in, and is compatible with APS-C format Pentax K-mount lenses in ‘crop’ mode.

The K-1 sells for slightly less than the popular Nikon D810 and has more features, but the Nikon’s system support and lens line-up is more extensive and the D810 has a better autofocus system. The K-1’s resolution is now slightly upstaged, too, by the Canon EOS 5DS, Sony A7R II, Sony A99 II and the brand new Nikon D850.

The Silver edition’s finish perfectly matches Pentax’s silver FA Limited Lens Series and you also get a limited edition metal hotshoe cover with logo. There’s a matching silver finish battery grip with two batteries,too, so the slightly higher price of £2,149.99 (UK) compared to the standard model makes it look good value.

Pentax K-1 Digital Full Frame SLR Camera Body – Black

Lomography Neptune Convertible Art Lens system

As well as making wide range of retro-themed film cameras and lenses, Lomography also makes ‘retro’ lenses for modern DSLR and mirrorless cameras, and its new Neptune Art Lens system goes a step further by introducing an new three-lens system sharing a common base mount. It won’t be available until 2018 but you can pre-order now, and it will come in Canon-fit, Nikon-fit and Pentax-fit versions, though adaptors for other camera types will be available.

The Neptune Convertible Art Lens system consists of a base unit which attaches directly to the camera’s lens mount, and three interchangeable front lens elements. These include a ‘Thalassa’ 35mm f/3.5 lens ideal for street photography, a ‘Despina’ 50mm f/2.8 general purpose lens and a ‘Proteus’ 80mm f/4 lens for shallow depth of field portraiture.

Also included is a macro adaptor for extra-close focusing and a series of six custom aperture plates for producing artistic bokeh effects.

The Neptune Convertible Art Lens system is manual focus only and designed for a slower, more creative approach. It won’t be cheap, alas, costing £839/$990.



Nikon D850 announced

Nikon D850

Nikon has announced its keenly-anticipated D850 DSLR. Unlike most high-end DSLRs, which offer a stark choice between high-speed continuous shooting or high resolution, the D850 offers both. It’s designed to appeal to professional wedding, landscape, nature and fashion photographers but its abilities are so broad it could be used for practically any kind of photography.

The D850’s key specs are a 45.4-megapixel full-frame sensor and 7fps continuous shooting, which rises to 9 frames per second with the optional MB-D18 battery grip. This also offers a duplicate set of controls for vertical shooting. The only other camera to offer this combination of speed and resolution right now is the Sony A99 II. The continuous shooting speed would be of little value without a big buffer capacity, but the D850 can capture 51 RAW files in a burst, which is extremely impressive.

Other specs include an ISO range of 64-25,600, expandable to ISO 32-102400, and a 2350K-dot 3.2-inch tilting touchscreen which also offers touch-focus and touch-shutter control. This works in conjunction with the new camera’s silent shutter mode, where it uses an electronic shutter and makes no sound at all, even when shooting continuously at speeds of up to 6 frames per second. This could make the D850 perfect for wedding and social photographers, sports photographers and even wildlife photographers. There’s also a 5-megapixel mode that shoots at 30fps.

The D850 has an in-built focus stacking mode which can be programmed with the number of shots required and the focus interval between each, together with an in-camera 4K timelapse movie mode and an 8K timelapse mode for use with external software for super-high-quality timelapse movies.

The video capabilities should attract film makers too. The D850 shoots 4K video using the full sensor area, so there’s no crop factor to take into account and movie makers will get full benefit from their wideangle lenses. This is in contrast to the Canon EOS 4D Mark IV, one of the D850’s chief rivals, which shoots 4K video with a large crop factor.

The control layout mirrors that of its predecessor, the D810, and Nikon’s other professional DSLRs. The D850 is weatherproof and has a shutter life rated at 200,000 actuations. The EN-EL15a battery is good for over 1800 shots on a single charge, giving the Nikon a big operational advantage over rival mirrorless cameras. It has two card slots, one for the new, fast XQD format and another for SD/SDHC/SDXC, which is UHS-II compatible.

The D850 goes on sale on September 7th 2017 and will cost £3,499/€3,899.00/$3300.

Camera types

Digital cameras come in a multitude of different types and sizes, and some of the jargon can be quite unhelpful. For example, ‘compact’ cameras aren’t necessarily compact and the real difference is that they have non-removable lenses. DSLRs and CSCs are both examples of interchangeable lens cameras, or ILCs, and these are differentiated by their design, sensor size and intended market. Most novices start off with a compact camera, move up to a DSLR or CSC when they become enthusiasts and then upgrade to a full-frame or medium format camera if they turn professional.

Alpha (Sony)

‘Alpha’ is the generic brand name used by Sony for its interchangeable lens cameras. This can be confusing because Sony makes cameras in two types – SLT (single lens translucent) and mirrorless models. Both are Alphas, but the Alpha A9 (mirrorless) and Alpha A99 II (SLT) are entirely different cameras with different lens mounts and lens ranges. Sony’s SLTs use Alpha A-mount lenses, while the mirrorless models use E-mount lenses.

SLT (single lens translucent)

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.

Alpha (Sony)

‘Alpha’ is the generic brand name used by Sony for its interchangeable lens cameras. This can be confusing because Sony makes cameras in two types – SLT (single lens translucent) and mirrorless models. Both are Alphas, but the Alpha A9 (mirrorless) and Alpha A99 II (SLT) are entirely different cameras with different lens mounts and lens ranges. Sony’s SLTs use Alpha A-mount lenses, while the mirrorless models use E-mount lenses.