Lens accessories

A run-down of the main accessories for lenses, including hoods, filters, adapters and ring lights.

Lens hoods

Lens hoods help to prevent stray light from entering the lens to create flare. They vary in size and shape and are usually short and rectangular or petal-shaped for wide angle lenses. Ultra wide angle lenses often have a shallow hood permanently attached.

Without an effective lens hood, strong, low-angle side lighting would have produced veiling flare and, possibly, flare artefacts in this picture.

Longer lenses normally use cylindrical hoods. Hoods for zoom lenses are often petal-shaped, with cut-out sections to cater for the wider field of view covered by shorter focal lengths. Hoods for zoom lenses must be correctly orientated; if they’re not, part of the hood intrudes into your shots. Most hoods have matte internal surfaces that are non-reflective.

Lens hoods are most effective when the sun is at an angle to the camera and out of view of the image frame. They can't block stray light when a bright light source is inside the shot.A lens hood also acts as a buffer between the lens and the environment, preventing fingertips from straying onto the delicate front element and leaving greasy marks that will degrade shots. Hoods on longer tele lenses also provide some protection against rain, spray and dust (although lenses that aren't weather-resistant shouldn't be exposed to the former). Some have impact-resistant rubber moulded around the front of the barrel for additional protection.

High-quality lenses like the zoom lens shown in this illustration usually come with petal-shaped lens hoods, which provide some protection against light showers as well as minimising the risk of lens flare in bright conditions. (Source: Nikon.)

While manufacturers normally provide hoods with more expensive lenses, they seldom do so with the cheaper, entry-level lenses. This strategy is essentially penny-pinching and environmentally unsound because most lens hoods are made of industrial plastic and inexpensive to produce.

A few third-party manufacturers produce adjustable hoods with a bellows-like design, usually made from rubber. They are generally conical in shape and attach to the lens via the filter thread.

Hard plastic hoods can normally be reversed over the lens barrel when not in use. Make sure you fit the hood properly before shooting. Hoods and other attachments should be fitted ‘finger-tight’ so they stay in place but are easy to remove.

Filters

Photographic filters are sheets of glass or resin that are positioned in front of the lens or (with some lens types) between the lens and the image sensor to modify the imaging light in some way. Although handy in some situations, their general use in digital photography and cinematography is debatable.

UV, Clear and Haze filters are largely unnecessary with digital cameras, although some people like to use them to ‘protect’ the lens from impact damage. Polarisers can be more worthwhile. However, unless you invest in top quality filters, cheap glass can degrade image quality and adding a piece of glass in front of a lens does very little to protect it.

Lens filters come in different shapes and forms, as shown below.

Circular screw-on filters are most common type. They attach directly to the filter thread on the inner surface of the front of lens and come in different thicknesses. Popular types include polarisers, neutral density and colour filters.

Square and rectangular ‘gel’ filters are normally made from optical quality resin that is light and virtually unbreakable. They must be mounted in a filter holder that attaches directly to the lens filter thread and can hold one or more filters.

A popular choice for landscape and other photography, these filters come in different sizes to suit different camera formats. The most popular types are neutral density, graduates (with different densities from top to bottom) and polarisers. They can be stacked together in certain situations, although this can negatively impact image quality and add unwanted reflections.

Plastic resin filters that can be fitted to a lens with a screw-on holder are available in different sizes and for different applications.

Drop-in filters are used inside long telephoto lenses where regular filters can't be fitted because of the design of the lens or the large size of the front lens element. Only ND and polarising filters are available.

There are two types of polarising filters, linear and circular. Linear polarisers are cheaper but can produce metering errors with today's cameras. Circular polarisers are used to reduce haze and suppress reflections off surfaces like water and glass.

The alignment of a circular polariser determines its effect, relative to the sun. The maximum effect is achieved when the lens is pointed at 90 degrees from the sun, where blue skies are darkened to make clouds stand out.

Watch out for unnatural sky darkening when using polarising filters, particularly with clear skies at high altitudes.

Always rotate the filter when you’re composing shots to find the best alignment. Avoid using them with ultra wide angle lenses because they can cause varying darkening in the sky. Watch out for unnatural-looking darkening in some situations, particularly clear skies in high altitude areas. Because of their thickness, polarisers can cause unwanted vignetting so as a general rule they shouldn't be stacked with other filters.

Neutral Density (ND) filters are used to reduce the amount of light that gets to the camera so you can shoot with slower shutter speeds. They’re handy when you want to blur moving water or when using fill-in flash to lighten shadows in bright outdoor lighting.

ND filters can also be used to slow shutter speeds when you’re shooting video to create more natural-looking motion, especially in bright conditions where low ISO settings aren't available.

The lower image in this pair shows the use of a graduated ND filter to selectively darken the sky, creating a more dramatic effect.

Graduated Neutral Density filters are dark at the top and clear from about half way down, usually with a ‘soft’ tonal transition. They are used mainly to stop sky tones from becoming over-bright and ‘blowing out’ to white in images and videos. Hard-edge graduated ND filters have a hard transition from dark to clear but it's essential to align the hard edge with the horizon.

You can also buy coloured graduates that let you add colours to skies or foregrounds. They’re seldom used for digital photography, since colour effects and white balance changes are best applied with post-processing software, which provides a wider range of adjustments.

Lens adapters

Lens adapters can greatly expand the range of lenses you can use on your camera and enable you to fit old lenses onto a modern camera. However, they also add weight to your camera kit and may cause some communication issues and reduce image quality. They’re best used as a transitioning aid when you’re moving from one system to another or swapping to a different camera brand.

There are plenty of options available. Leading manufacturers like Canon and Nikon offer DSLR lens to mirrorless mount adapters, while companies like Fotodiox, Techart and Metabones produce adapters for swapping between brands and formats.

Lens mount adapter to fit a Nikkor DSLR lens to a Nikon Z-mount camera. (Source: Nikon.)

‘Smart’ adapters can transmit electronic signals between the camera and the adapted lens, which means autofocusing and auto exposure will work almost as well as they do with the camera manufacturer's lens. Most will record the EXIF metadata for the lens. ‘Dumb’ adapters lack electronic communication and require manual control over focus and exposure settings. Many don't record the EXIF metadata, which can be problematic in some cases.

A few adapters (mainly from Metabones) act as ‘Speed Boosters’ by reducing the effective focal length of the lens to increase the effective lens aperture by up to a stop.

Ring lights

Ring lights are often used for macro photography because they provide an even spread of light over the subject, usually with little in the way of dark shadows. They can be either flash tubes or an annulus of small LED lights, both of which are attached to the front of the lens barrel. They are usually simple to work with and surprisingly versatile.

Ring lights that fit directly onto the front of the lens produce soft, shadowless lighting that is ideal for close-up photography and can also be used for close-up portraits. These illustrations show two different types: LED and flash. It's important to note that their light output can seldom illuminate subjects more than about 80 cm from the camera. (Sources: Canon and Godox.)

Ring lights can produce a soft, even distribution of light, so they are often used for portraiture, particularly for glamour shots. Product photography is another area in which ring lights are useful, especially for close-ups of jewellery, flowers and other small items.

Both kinds of ring lights are battery powered and the batteries may be stored inside the unit (in the case of low-power lights) or in a separate module that is attached via a cord. Some are triggered by a unit that attaches to the hot-shoe on top of the camera, while others require a remote control.

AppsDownloadable apps that let you update the firmware on a lens you own are also entering the market. Check out the offerings from Tamron and Sigma, with the latter requiring you to purchase a USB dock to connect the lens to your computer. Sigma's dock also lets you access software for customising the lens controls.

Newer lenses from other manufacturers are usually updated by connecting the camera you’ve fitted them on to the internet via a USB cable. For older lenses you must download the new firmware to a memory card in a card reader and then insert that card into the camera to install the firmware.

Useful links

When to use filters

Lens accessories

This article by Margaret Brown is an excerpt from Lenses 2nd Edn pocket guide

Pocket guide Partner: Camera House