crash course 5: filters - what, how, when, where and why

It's my birthday today - yay!  And the penultimate day of this course you'll be glad to read.

A famous photographer (whose name I cannot remember!) once said that you see an image with your heart and mind, not with your eyes.  This is a philosophy that I try to uphold whenever I shoot a landscape image.  I don’t take a picture of what is in front of me, but one that I feel and sense emotionally.  Does the scene make me feel warm, scared, cold, happy?

I use all the tools at my disposal to record those feelings.  My camera of course, and then my lenses and filters all combine to manipulate the scene to arrive at the image I want to make.

Filters come in all shapes, sizes and of course, prices.  I use the Lee 100mm slot-in filter system, and use filters from Lee, Kood, Formatt Hitech and Haida in it.  You can also get screw-in filters but I find the Lee system more versatile.

The slot-in system is useful as it allows me to stack my filters.  I can fit up to three filters in the slots along with a circular polariser which then screws onto the front of the Lee holder.  I regularly use a combination of a neutral density, graduated and polarising filter.

Using these filters can complicate matters though, and I have to compose and focus manually before employing my filters, as the darker filters in particular make it hard to see the image accurately through the viewfinder or on the camera's screen.

More stops of light also mean that my camera is sometimes unable to calculate an exposure time.  Therefore I have to manually calculate the correct shutter speed (or use an app provided by Lee) and shoot in a mode that allows me to accurately time my exposure.  Also, when shooting really long exposures (say 3 minutes or more) at sunrise and sunset, things are further complicated as the ambient light is constantly changing throughout the exposure.

While all this sounds really complex, with experience I have learned to overcome most of these problems; most of the time!  Also, my newer mirrorless cameras are much easier to use though than the DSLR cameras that I used to employ.

My circular polarising (CPL) filter:

This is an essential for any landscape photographer.  It consists of 2 pieces of glass: one fixed and one which is rotated to deliver the degree of polarisation you need, and is not named for its shape but for the type of polarisation it provides.

my Haida 105mm CPL filter

A CPL filter has two basic uses: to saturate colours and to reduce glare or reflections.  Both are controlled by the degree to which you rotate the filter.

So, if I’m faced with a nice vivid scene, I can use my polariser to further emphasise those colours and make the scene more colourful than it may appear.  This is particularly useful in woodland scenes to saturate the verdant hues there.

When it comes to photographing water, I often don’t like the brightly reflected surface often present.  The polariser helps to cut through this glare and makes objects underneath the water more visible.  It can also be used to photograph through glass by removing unwanted reflections.

You have to be careful where you position your camera in relation to the sun (90 degrees is optimal) or to the reflected surface you’re working with (45 degrees or so here) to get the best results.

 I used my CPL here to cut through the reflection on the rockpool – just a little though

And here I used it to saturate the autumn colours in the scene

A by-product of the CPL is its “stopping power”.  By which I mean it acts to stop a small amount of light (usually by 1-2 stops) and therefore is useful to slow down my shutter speed if I want to introduce blur or a sense of motion into my image.

My neutral density (ND) filters:

Speaking of stopping light I employ one of three filters that enable 3, 6 or 10 stops of light.  This allows me to really slow down my shutter speed for that really milky water or dreamy sky effect.

My 10-stop filter – an almost black piece of glass

Alternatively, I can use an ND filter to shoot with large apertures if I want a shallow depth of field but there is too much ambient light otherwise present.  This is useful for shooting macro images or portraits in the middle of the day.  And essential for shooting video where slower shutter speeds (1/48th of a second or so) are the norm.

My 10-stop filter gave me a 1-minute exposure here – creating a really calm image

ND filters really allow me a high degree of creativity in my image making and together with my CPL they are essential tools as the look they give you cannot easily be reproduced in post processing software.

Also, my Lee 6 and 10 stop filters give my images a blue colour cast, making them look cold which can be useful.  If I want a warmer look, then this “coldness” is easily dealt with by adjusting the white balance in post processing (as long as the image is shot in "raw" mode).

As I've already mentioned, using the darker ND filters necessitates composing and focussing the image manually prior to inserting the filter, and then calculating the correct exposure time.

My graduated neutral density (ND grad) filters:

Often cameras are not able to capture the dynamic range of a scene that our eyes can, particularly at dawn and dusk.  If I expose an image for the shadows, then it’s likely that the highlights will be “blown out” and beyond recovery in post processing.  Similarly, if I expose for the highlights then shadow detail is lost.

I like to overcome these difficulties by employing my ND grad filters which allow me to correctly expose for the overall scene without losing detail.  I tend to expose for the shadows and then employ my filters to control the scene's brighter areas.

 My 3-stop graduated filters (reverse filter on the right)

Sometimes, though, not even my filters can overcome dynamic range and I’ll need to shoot “bracketed” images – usually one for the highlights and another for the shadows – and combine them in post.

Some photographers prefer this method to using ND grads at all, but I still prefer to get things as right as I can in camera in one shot.  Also, some post processing software now allows for an artificial ND grad effect, but again I prefer to keep things as simple as I can.

I use 2 ND grads, both of which give 3 stops of light over the brighter part of an image.  One is a soft-edged ND grad which is useful in shooting scenes without a definite horizon. 

The effect of the filter is shown here – “holding in” the detail in the bright sky

The other has a hard edge and fades out from the middle to the top – a reverse ND grad filter.  This is particularly useful when shooting sunrise or sunset at the coast, enabling me to shoot directly into the sun without losing too much shadow detail in the foreground which, without the filter, would just be in complete silhouette.

The image above is one where I combined three filters: a CPL to cut through the rockpool's reflection, a reverse ND to balance the exposure between the foreground and the sky and a 3-stop ND to slow down the exposure giving a calm, dreamy look to the sky and sea.

So, these are the filters I use personally.  But of course there are many others which perform many varied tasks such as colouring images or for shooting sunbursts.  Also, film photographers will still use various filters to adjust for different lighting scenes or to artistically manage their images (e.g. using a red filter to darken blue skies).  If I choose to shoot black and white though, my Fujifilm cameras have built in filters for these purposes.  Thanks Fuji!

Many photographers also use UV or "skylight" filters.  While essential for film photography they are largely redundant in the digital world but can be used to protect the front element of a lens.  Personally I do not use these but many photographers swear by them.

Oh, that qoute from the start of this post?  Dorothea Lange.