Advanced Tutorial 12
Rather than leaving adjustment of your images to post-processing, why not try fitting a filter and capturing the effect you want ‘in camera’? There are many types of filter available and in this tutorial we look as the most popular and their uses, and at money-saving converters, too…
Using lens filters & converters
This tutorial looks at ‘supplementary’ filters and converters – as these are devices fitted to the front of your lens, not between it and the camera body.
In today’s digital world, we can add filter effects using software post-shooting, whereas previously photographers would carry a selection of filters to control the light and add ‘special effects’ as they shot. So, let’s look at a selection of modern filters you can attach to help control exposure and enhance your results while shooting.
Filters are fitted via the screw thread on the front of lenses. Diameters vary from 37mm upwards, so check carefully the size you require before purchase! Thread diameter is normally indicated on the front of each lens.
If you have multiple lenses (or cameras), you can buy ‘stepping rings’ to accommodate filters of various sizes; generally, it is preferable to use rings to fit larger filters onto smaller lenses, not vice-versa.
Always buy high-quality filters to maintain image quality and remember, with a filter in place you can still fit the protective lens cap.
Types of filter
The most commonly used filter is the ‘UV’ or ‘Lens Protector’, e.g. Panasonic’s DMW-LMC52 (right), manufactured using multi-coating technology to maintain maximum light transmission, hence the prefix ‘MC’ on the outer rim.
Appearing clear to the eye and with no noticeable effect on colouration or exposure, these filters serve two purposes: they block UV light, which tends to cause a distant haze in landscape photography; and they protect the front element of the lens. Many photographers fit these to all their lenses/cameras, permanently – you can mount another filter on top, but take care not to over-tighten them against each other.
The next most popular type is the PL or ‘Polarizing Filter’ sometimes referred to as ‘CPOL’ (Circular Polarized), which restricts light passing through the lens so only that being reflected directly parallel to the axis passes to the sensor.
Modern auto focus cameras require the use of a circular polarizing filter rather than the older linear polarizing filters. This does not refer to the shape of the filter, rather the way in which the polarization is achieved.
These filters do reduce exposure levels slightly, typically by around 1.25 stops – so can be used to help achieve a particular exposure, but their main use is in reducing glare/reflections from highly reflective surfaces and increasing the saturation of brightly lit scenes.
Polarizing filters are made in two pieces, the front section of the filter rotates, and there is a machined ring that allows your fingers to grip the rear section more easily when fitting. Once you have mounted the filter, turn the front ring in either direction (it rotates a full 360 degrees) and you will see the image on the screen, or in the viewfinder, darken as the level of polarization increases. Compose your picture and then adjust the ring until the scene views at its darkest or the reflections are reduced as much as possible, you have then set it for maximum polarization.
Another common filter type is the ‘Neutral Density’ – photographers use ‘ND’ filters when trying to work with a particular aperture/shutter speed when a scene is too brightly lit for the exposure required. ND filters are available in different densities, commonly ND2, ND4 and ND8, reducing exposure by one, two and three stops, respectively. Shown right is Panasonic’s ‘ND8’ rated filter.
Although these filters increase the required exposure – they are commonly used to control levels for video work – they are colour neutral and have no impact on colour reproduction.
These diagrams illustrate the effect of different strengths of ND filters, starting with the ND2 allowing half the light to pass through, then a quarter, then an eighth:
As an example, when you need a slower speed than the available light permits, Panasonic’s optional ND filters are rated ND8 and will reduce the required shutter speed from a 1/30th of a second to 1/4th, allowing for some interesting effects.
There are many more types of filters available – Starburst Filters add a ray-like pattern emanating from highlights; Soft-focus Filters create a ‘dreamy’ look; Coloured Filters can add warmth or cool down a scene; and it is possible to purchase Graduated Filters, only partially coated with a portion left clear with no impact on exposure – useful for balancing between a dull foreground and a very bright sky.
Not to forget that many modern cameras offer creative filter effects ‘in-camera’ that do a similar job to these types of supplementary filters, and of course as mentioned previously, today’s photographers often choose to use software to create such effects post-shooting.
When to use filters
There are no hard and fast rules, so don’t be afraid to experiment! But here are some useful examples:
- Circular Polarizing Filter – when shooting over water, it can cut through the reflective surface to reveal details beneath – see this example of a garden pond with and without filter:
On bright days, a Polarizing Filter can help to saturate the colours in landscape shots, making the sky more intense, the clouds more defined. The degree of polarization depends on the angle light strikes the lens, so try positioning yourself at right-angles to the major light source for maximum effect. In this example, the greens in the foliage are saturated and sky details are revealed with the filter, as opposed to without:
- ND Filters – popular with landscape photographers, as they allow a slower shutter speed to be used on bright days for deliberately blurring, giving the impression of motion, most commonly used with flowing water – see with filter and without here:
Don’t forget to support the camera securely when working at these longer exposures, as it is movement of the subject that needs to be emphasized not movement of the camera.
Converters or Conversion Lenses
Designed to screw onto the front of existing lenses, converters come in four general types: Telephoto, Wide-angle, Fisheye and Macro.
Telephoto converters increase the telephoto effect of any lens – a cost-effective way of giving you a higher magnification. Wide-angle (and fisheye) converters work the opposite way, providing an increased field of view. Macro converters are often designed to be used with a specific lens to replicate the effect of a dedicated macro lens.
Such supplementary converters may not yield the highest levels of quality offered by dedicated lenses, but they do provide a way to experience the same effects. See the following examples of converters in use:
- Tele Conversion lens – gives you more reach for distant subjects. Remember to account for increased relative focal length when selecting shutter speed, to avoid camera shake. Here, you can see how a 2x converter on a 42mm (84mm equivalent) lens turned this shot into a 84mm (168mm equivalent):
- A Wide-converter increases field of view – ideal for use in cramped interiors, but hold your camera as level as possible to avoid increasing perspective distortion. Using a 0.79x converter on a 14mm (28mm equivalent) lens turned this shot into a 11mm (22mm equivalent):
A Fisheye-converter produces a distinctly rounded distortion. Panasonic’s DMW-GFC1 is designed to work with either the LUMIX G 14mm f2.5 (H-H014) or LUMIX G Vario PZ 14-42mm f3.5/5.6 lens (H-PS14042) for effects like this:
Macro-converters – such as Panasonic’s DMW-GMC1 used with the LUMIX G Vario PZ 14-42mm f3.5/5.6 lens (H-PS14042) – achieve striking macro results with super-close focus:
The LUMIX Advantage
Panasonic’s LUMIX range includes top-quality lenses that can be supplemented with specifically designed compact and lightweight converters, plus a range of high-quality multi-coated filters, to achieve superb results for the most demanding of photographers.
As a start to your experimentation, try a Polarizing filter with a subject in bright directional sunshine. Don’t rotate the filter at first – view from different angles, shoot from different positions and notice how the polarization effect varies according to the angle of light falling onto the subject. Then alter the affect to get used to making adjustments.
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