Filters Are Our Friends

Posted by Jimmy America on Mar 28, 2010 in Advice | 4 comments

What are filters?

Filters are pieces of glass (or plastic if you get ripped off) that have different properties to manipulate the light that is going into the lens of your camera. They come in all kinds of shapes, sizes, colours and most varied of all, price$. There are oodles and oodles and oodles of filters, so I just thought I’d touch on all the useful ones and then go into a few of the funky ones.

Types of Filters

I’m sure that different companies have invented some obscure ways of attaching filters to lenses such as Rollei and Hasselblads bayonet system, but there are two main systems. First there is the simple cap system that screws in. These kind of look like clear (or coloured as I will get to) lens caps that just screw onto the front of your lens. Nice and easy. The other main mounting system is the Square and Rectangular Filter system, which is predominantly used by Cokin and Hoya. In this version a mounting system is fixed to the front of the lens and then the filters (Which take the shape of glass squares or rectangles) slide into the front. Different people swear by different systems, but to be honest they both have their ups and downs.

For example, with the round thread mounted system, you can stack as many filters on top of each other as you like because they just screw into the next one. The square system is limited to the amount of slots in your mounting bracket. With the rectangular system you can control the amount and position of the gradient if you are using a graduated filter, for example, if you wanted to add more blue to a sunset, but not the rest of the photo.

What filters do what? Well I have tried to organise this section into two groups. What I call “The Useful Filters” which produce results that can’t be replicated in photoshop and “The Funky Ones” that are fun, but you could also do to the photo later in post-processing. I find this a little bit useless because in photoshop you have much more control over the end result. With that said, all you sepia filter fans can start sending me letter bombs now. I’m going to give a little description of what some filters do, but for the most part the names kind of give them away, so bear with me.

Useful

• Close-up/macro – Does exactly what the name says. These will allow you to take a much closer photo. The close up one comes in 1,2,3 or 4 diopters (look it up, I had to) and apparently give a very shallow depth of field and the macro filter will double the magnification of your lens.

• Polariser – A polariser will allow you to remove unwanted reflections from non-metallic surfaces such as water, glass etc. They also enable colours to become more saturated and appear clearer, with better contrast. This effect is often used to increase the contrast and saturation in blue skies and white clouds. I could go into the science behind how it does this, but it can take a little while, so if you want to know then you can look that up while you are looking up ‘diopters’

• Infrared – Infrared filters only allow infrared light through. They were originally designed for film cameras using infrared film, but people have started using them on their regular DSLRS to achieve some spectacular results such as the photo below by Torsten-Hufsky. As you can see, Thee green of the grass and trees are turned white and the blues can sometimes turn black. More information on infrared photography can be found HERE.

• UV – These absorb ultraviolet rays which allegedly makes them sharper. Because this isn’t really a bad thing, people have started attaching them immediately to new lenses as a protection filter. Meaning if it gets scratched or dirty beyond repair, you only have to replace the filter and not the entire lens. However if you really want to protect your glass, you should buy a protection filter.

• Protection - Hoya makes a protection filter that will do nothing to your photos and is heat-treated to become 4 times stronger than regular glass. It is also coated to become finger print and oil resistant. THIS is what you should be using to protect your glass.

• Neutral Density x2 x4 x8 x400 half ND - Think of a neutral density filter as sunglasses for your lens. There are three main uses for these.

• Taking photos of and around snow where bright lights would normally cause over exposure.

• To decrease depth of field by allowing wider apertures to be used, which helps separate subjects from their background.

• To allow you to use a slower shutter speeds and capture motion.

Number three is pretty much all I use mine for and I love it. If you shoot landscapes, you need to have one of these. Using long shutter speeds while taking photos of mountains at sunset will allow you to turn the clouds in the sky into long streaks of colour. This really adds something to what can be ordinary photos. The photo on the right was taken using an ND8 filter at sunset and the exposure time was 30 seconds. Other examples of when this can be useful are when taking photos of waterfalls, streams or oceans, lightning or capturing the motion of cars in bright situations.

An ND2 filter wont filter out much light, but an ND8 will. You can also put two ND8 filters on top of each other to get an ND16. Hoya has also released an ND400. Good luck taking portraits with this one, It’s main use is for taking pictures of the sun! If you are using a rectangular system then you can get graduated ND filters to darken the sky or use a longer exposure on the ground. Very useful stuff.

• White Balance – Instead of carrying different grey cards you can just pop this cap on and adjust your white balance in camera. Yes this can be replicated in photoshop, but it is easier just to properly expose the shot in the first place.

• Underwater – These filters aren’t for waterproofing, they are coloured filters that allow you to properly expose your photos and counter-act the colour of the water so the colour of the coral and fish come out looking great.

Funky ones

• Colour-Spot – A coloured filter with a hole in the middle. This is useful for adding a vignette to photos if you like them.

• Intensifiers – Also known as a ‘didymium’ filter, this is used to enhance red, orange and brown subjects to give more colour saturation and contrast, whilst having very little effect on other colours. Good for landscapes and sunsets.

• Sepia – If you are looking for that wild west look then these are the filters for you. They come in different grades and will add different amounts of brown to your photos.

• Coloured – These are just different coloured glass filters. Ironically by using coloured filters you can really boost your black and white photography, particularly yellow and green glass.  Again these can come in graduated filter squares to add more blue or red to a sky.

• Dual & Tricolour – Just like coloured filters, but there are two or three different colours on the same filter.

• Soft diffused - Also known as Soft-Spot, Fog filters and Softeners, these give a very soft focus to photos, like soap operas from the 80’s. The same result can be achieved by adding Vaseline to your lens, but that gets messy.

• Cross Screen – These filters turn lights into pretty twinkly stars. Well, they are supposed to be pretty, I just find them annoying.

• Multivision – Basically this one turns your lens into a kaleidoscope.

Something to check before you buy ANY of these filters is to check out your in-camera editing system. My D60 is an entry-level camera but it can create sepia, black & white, intensified, white balanced and cross-screened images before they even leave the camera. And more! Something else to think about is the quality of the filter you are going to use. I think that when you buy Cokin or Hoya, you do pay for the name and they do get ridiculously expensive ($189 for one freaking filter!!!!) BUT they do have their image test results available and they are high quality glass. It doesn’t make much sense to go out and buy a $1,300 lens and then stick a $15 filter in front of it because the quality of the lens glass is just going to be let down by the quality of the filter glass. Then again, if you can afford a $1,300 lens, why are you buying $15 filters? Stop being so cheap! And give me your lens! =(

If there are important filters that you think I should have mentioned here (and I know I left some out), please comment so other photographers can gain from your fountain of knowledge!