Lens filters are fabulous little gadgets to have in your photography toolkit. 

By having a bunch of filters at your disposal, you can make beautifully creative and polished pictures without the need for an arsenal of expensive camera lenses. 

The main job of a filter lens is to provide a variety of creative solutions. Plus there’s the added benefit of giving your lovely camera lens a level of protection. 

In this blog we’re going to jump into how they work, what filters are available and what they each do, so you can work out when and where you might want to use them.

So how do lens filters work?

Well basically they alter the characteristics of light passing through the lens. 

It's important to note that using a filter usually requires altering the exposure to compensate for this. We like to call this the Filter Factor.

When you encounter extremely difficult lighting conditions a filter can make a world of difference. Enhancing colors, changing lighting and contrast, reducing unwanted reflections and even adding a selection of special effects.

They're nice to have to hand instead of relying on post production editing. Although, Lightroom and Photoshop can still get you the same effects if you know how to use them… So it depends whether you want to spend a lot of time at your desk or not!

Not all photographers will opt to make use of lens filters. To be honest, a lot of genres just don’t require them… If you’re into landscape photography - using filters is probably going to be something you will want to do.

Photo by Scott Gummerson on Unsplash

What types of lens filters are on the market?

There are many. But the important thing to remember is they aren’t always one-size-fits-all. 

For example, if you’re using a Canon, you might not be able to properly use a Nikon or Sony filter. Some do offer adapters, but this doesn’t always work out perfectly. It comes with limitations e.g. auto-focus or auto-aperture might not work. 

The good news is that most brands that create digital cameras, will offer filters. So you can expect to buy one that’s perfectly suited. Plus, a lot of them will be universal - but be aware to always check before buying.

The most common type are round screw-on filters, which attach straight to your camera lens. However, you can also get square and rectangle drop in/slot in ones. Your camera will require a filter lens holder if using these. 

Filters come in a variety of materials too: glass, plastic, resin, polyester and polycarbonate. 

• Glass is generally the most expensive to buy, it’s also the most fragile. 
• Polyester filters are brilliant quality. They are also thinner, but alas they’re prone to scratches. 
• Plastic and resin filters are cheaper and more durable, however don’t expect the quality to be as high. 
• Polycarbonate filters are pretty tough and scratch-resistant, they’re considered a decent alternative to plastic/resin filters.

If you’re thinking about purchasing a camera, and reckon you’ll want to make use of filters, it’s a good idea to consider all of this initially. Always spend a bit of time researching, ask others who do similar styles of photography, read up on reviews etc.

Let’s move on and talk about some of the actual lens filters out there, and what they do.

Polarising Filter (or Polarizing Filter if you’d rather)

Landscape photographers often warm to polarising filters, due to the fact they are great at reducing haze. These filters also make bright colours brighter, create bluer skies, reduce reflections, and give a higher contrast to images.

It’s important to remember that these filters have both a minimum and maximum effect. AND are relative to the sun. i.e. when the lens is pointed 90 degrees from the sun, you’ll be at maximum effect.

To use the filter you just need to turn it to achieve your desired result. If you want to take it further, that’s something you’ll need to do post-production.

Here’s a before and after of an image taken with and without a polarising filter in place (See the original video here).

If you’re using a DSLR, you’ll be looking for circular polarising filters. They don’t cause any metering issues like the linear version will do. The way they work is basically the same, it’s just the construction that differs. 

Ultraviolet (UV) Filter

UV filters are transparent and block ultraviolet light. Previously that was their main use. However, modern DSLRs already have a UV/IR filter in front of the sensor and therefore don’t require this added extra. So what’s their use now?

Well they are mostly used simply to protect your lens from dust and scratches. Often being mounted permanently onto a camera lens.

As always there’s often a great debate about whether to use or not to use. The problem being that adding a layer in front of the lens can reduce the quality. And who wants that?

However, if you like the idea of a bit of lens protection, I would probably recommend a glass one with a multi-resistant coating (MCR) just to be sure it won’t dampen the lens quality. 

Neutral Density (ND) Filter

Imagine popping a very dark pair of sunglasses over your camera lens. That’s the job of a ND filter. It’s used to reduce the amount of light entering the lens so you can set slower shutter speeds.

Don’t forget - if you’re thinking of slowing your shutter speed, use a tripod. If you don’t stabilise the camera, you’ll end up with too much bokeh for anyone's liking! 

If you're into shooting landscapes cutting out light can help you create some beautiful and dramatic effects like 'misty looking' water. Take a look at the image below to see what I mean…

ND filters come in different densities of dark - but they are of neutral colour i.e. no colour at all. The darker the filter the less light it will admit. Pretty simple.

You can stack neutral density filters to slow shutter speed even more, or if the light is so bright you need to reduce the amount entering your lens further.

My favourite is the Lee ‘Big Stopper’ which loses ten stops of light and is incredibly dark. 

I’ve got a nifty 3-part video series that goes into using ND filters with Tom Mackie, an expert in the filter game - take a look here. 

ND Grey Grad Filter

Graduated Neutral Density - or GND filters - also exist. These are fab things to have in your kit and one of the easiest and most effective filters you can buy. 

The difference between these and standard ND filters, is that half of the filter is clear.  

They work by evening out the exposure between really bright and really dark areas, bringing the difference in contrast together. Fab if you’re shooting a scene or subject where the contrast in brightness is very different i.e. bright sky, dark land. 

If your photo contains the sky on a bright day, without a grey grad filter your camera won’t pick up the cloud detail as you see it with the naked eye. Pop the filter on and voila, you’ve got the finer detail that adds that realistic touch to your sky. 

Close Up Filter

If you’re into macro photography, or maybe just want to dabble and would rather not buy a dedicated macro lens, these filters are your next best option. 

Close up filters are actually more like a lens than a standard filter. Basically it's a magnifying glass that you pop on the end of your camera lens that allows you to get in close, but still get good focus. 

You’ve probably guessed it, these filters come in a variety of magnification powers. 

Another really excellent thing is that they have the ability to be stacked. This allows you to get extremely close to the subject, magnify the pants off it and end up with a nice crisp macro image.

The image below was taken using close up filters, stacked onto a standard 18-70mm lens, and in auto-focus.

I’d have never gotten in this close, capturing the amount of detail and sharpness I did without using the filters. Watch me test out the different magnifications in my Close Up Filters video. 

Special Effects Filter

All 'special effects' filters should be used with caution but with a bit of thought and planning they can result in some interesting images.

For example, have you ever been somewhere and thought it'd look great with a sunset - but the sun won't set where you want it to? Don't just think you can pop on a sunset filter, take the pic and it'll look great!

You need to think about light, composition and all the other things that come into frame. 

Imagine it’s the middle of the day, you’re not going to have the kinds of shadows that are created when the sun sets. So if you try to forge it, it’s going to look all wrong unless you have the natural elements of a sunset in frame…

Personally, I wouldn’t spend too much time, or money, on these lens filters. You can create lots of special effects post production - more than you could with a filter. 

In conclusion

So we’ve covered what lens filters are, how they work in general and some of the main types you can buy. 

We now know that one of the key benefits of filters is that they can really help with difficult lighting conditions. Natural light is something we cannot change or control, there’s no dim switch. Using filters is a clever way to achieve desired results, without the need to pray to gods of the sky.

Other uses are managing reflections, exposure and colours, protecting camera lenses, offering macro zoom and differing special effects.

Remember if you want to explore your photography using filters, do the research, check if they will work with your camera lens and whether they will actually help you get the look and feel you’re after.

If you want support with your photography, whether that’s to learn the basics and photography fundamentals, or to polish your current skills and knowledge, I’ve got some great courses that will help you.

Otherwise keep a check on my blogs, utilise my bank of free video tutorials and book yourself on any of my upcoming webinars.

Your photography needs you!