When it comes to filters for digital camera, you’re mainly dealing with UV, Polarizing, and Neutral Density filters. There are variations of these filters, such as a graduated ND filter, but these are the key filter that you would want to use. There are plenty of gimicy special effect filters, but we won’t be covering those in this post.
We can’t see UV light, it’s invisible to us. But then, why would we want a UV filter? It’s because our cameras can see what our eyes can’t, including this UV light. This UV light often appears as a haze, which we like to remove.
In actuallity, this is problem that effects film shooters, and rarely digital shooters. Digital sensors are much less sensitive to UV light.
Why still use one? Well, I never take mine of the camera, as it will protect the front element of my lens, so that if I’m clumsy and accidentally knock it, it’s damages my filter, and not my rather expensive lens.
If you buy a good enough quality filter, you can’t even see the glass, so there is no damage to your image quality. This statement will be argued with, as some people seem to think it does, but I think that’s mostly down to poor quality filters. I don’t see a problem at all.
If you have an expensive, professional lens, which you would like protected, use a UV filter.
Polarizing filters are really useful, because they reduce glare, and improve the saturation of photos. The effect created by a polarising filter is one of the only effects that can’t be replicated in post production so it’s important that you own one.
I would say that most people who use a DSLR, should buy a polarizing filter.
There are 2 types of polarising filters; linear and circular. Linear are traditionally used in film photography, where as circular is used in digital as they’re designed to not confuse the camera’s autofocus. When you attach the circular filter to the end of your lens you’ll find that you can still rotate the filter, which changes the direction that the light is polarised.
When shooting in direct sunlight, you’ll often find that your images come out harsh and feel overexposed. Think of it as being in the sun with no sunglasses on, it’s hard to see. Polarisers work by only allowing light from a certain direction, which removes the glare from photos.
Of course, there’s more to it than that, read more about them here.
Neutral Density (ND)
Neutral density filters are used primarily to decrease the shutter speed. The way they work is to reduce the amount of light entering the lens at once, which means that if you want to correctly expose, you need a longer shutter speed.
Why would you want this? Well, sometimes it’s nice to capture movement in your photos, but there’s too much light and the shutter speed is too fast, even with a narrow aperture. This is where the ND filter comes in. It reduces the amount of light hitting the sensor, which allows you to decrease your shutter speed, without ruining the exposure.
You might also want to capture no movement at all. This can be done when you take a really long exposure, for a few minutes with people passing through the scene. The result is a photo which is devoid of any people.
If you’re a landscape photographer, I would thoroughly recommend one of these. They come in different values, depending on the amount of light you would like to block out.
This is the same as above, only the ND filter is only on one section of the filter. This will help you to evenly expose your photos.
Imagine you’re taking a photo of a landscape, and the sun is in the background; you’re going to encounter a problem. The sky becomes over exposed, and the foreground becomes underexposed. Rather than defaulting to HDR, you can use a graduated filter, which will darken the sky, and leave the foreground as it is. This will result in a much more even exposure.
White Balance Filters (Warming/Cooling)
These filters will make your photos look warmer and colder, effectively changing the white balance. They’re basically out of date now, as we can change our white balance as we please. When film was more popular, these were used a lot, because film is set to a single white balance that can’t be changed.
A little history lesson for you there.
How To Choose A Filter
You want quality? You have to pay for it. I’m of the opinion that you need to invest in the right ares of your gear, and lenses and filters is definitely where you should be investing.
Go for a good name-brand filter, such as Hoya, and buy the best one you can afford.
Check the diameter of your lens first, to make sure you order the right size. Some kit lenses are usually 52-58mm in diameter, mine is 72-77mm depending on the lens. The wider the diameter, the more expensive the filter.