Focus: Filters

Focus: Filters

There are many kinds of filters you can use however the main point I want to make is about protecting your lens but first, what is a filter?

A filter for a lens is a piece of glass that is somehow attached to the front of the lens to stop certain light or all types of light from getting through.  Some filters are for Ultraviolet (UV) light which has a small effect on your photos.  I believe it effects the blues of your photos but I could be wrong there.  Another main type of filter is called a polarizer.  This behaves the same as polarized sunglasses which I will explain more later.  There are also filters that just darken your photos called neutral density filters, aka ND filters.  These are like putting sunglasses on your lens to block out a lot of light.  There are also graduated ND filters that have a gradient or a change in darkness from the top to the bottom.

So why have filters? Well it depends on what you want to get from them.  And here is my major point... UV filters are $20-60 (or so) pieces of glass you can screw onto the front of most lenses but secretly do more than block the UV light.  They protect the front element of your lens!  If you accidentally scratch the front of your lens, and you have a UV filter on it, then you just buy a new one for under $100.  However if you didn't have a filter on the lens and scratch the front of it against something... then you have to replace the front piece of glass in your lens or buy a new lens.  Both of which are costly.  However just as the price difference suggests between a filter and the front element on your lens, there is a quality difference as well.  So this is where some people disagree on UV filters for protecting your lens.

Yes, it is almost a no-brainer to want to protect the front of your lens from scratching and such.  Also it is easier to clean cause personally I am way more hesitant to try to clean the actual lens than a UV filter.  However because you are adding a lower quality piece of glass on the front of your lens, it could effect picture quality.  How?  Not sure.  I haven't done much testing with my UV filters on and off.  But I just know the filters are not the same quality of glass so it would effect your photos a little.  How much much?  Not sure but I am will to sacrifice some quality for safety since if I scratch my lens then my image quality I know for sure will go down.  So would my bank account.

So now that my main advice point is made I will go into some detail on the other filters.  UV filters are usually the more inexpensive so they are often what is recommend to just always stay on your lens to protect it.  Now I will move onto the polarizers.

Polarizers can be normal (linear?) or circular.  But first I will explain what it does.  So first some physics.  Light travels as a straight line and when it reflects on uneven surfaces the light starts traveling in all sorts of directions.  So when light hits water, it reflects and sparkles but that light is now not all traveling in the same uniform direction.  So what a polarizer does, is it filters out the stray scattered light so that you only get light that is traveling in the same plane or direction.  So what this does is it lets your colours in your photos be more vibrant because there is less scattered and excess light to kinda "bleach" out your photo.  So the greens are brighter and more strong because there isn't extra light just increasing the lightness of the photo.  These filters allow you also to take pictures of objects that usually reflect a lot of light as well.  So like the surface of water, or a freshly washed car.  The polarizer will cut down on the scattered reflected light.  Polarizers can be non-circular or circular and that I believe just tells you how the glass is designed to filter out the light.  But all you need to know is the circular ones are more expensive because they filter out the light is a better way.  So if you do a lot of landscape photography this may be for you.  However, if you have a ultra wide angle lens, they are pretty much useless because the view is so large the polarizer wont be uniform for the whole photo since the view of the lens is so large.  However on my 18-105mm lens it was great.  Another disclaimer is that these filters let less light in which means you need sunnier days or a tripod to take landscape photos because it is like wearing sunglasses as I said.  So everything will be darker and your camera will want to compensate for that decrease in light.  Smaller aperture values (larger diameter) or slower shutter speeds or last case, higher ISO.

ND filters are filters that are not polarized however are used to just darken the photo.  So if you wanted to do a photo of the slower shutter speed on water like this one:

Lavender Falls - 17-55mm - Tripod

But it was a bright sunny day and you had to use to fast of a shutter speed to get the correct exposure, then you would wish you had just normal sunglasses to just block out some of the light.  That is what a neutral density filter does.  As the name implies, the density of the filter is neutral and is just a solid darkness.  The other type of filter in the category is a graduated filter.  These are like some female sunglasses where the top is darker than the bottom.  So if you nod your head up and down (I don't advise you do this in public) you will see that there is a difference is how much light gets through between the top of the lens and the bottom.  The filters (or some female sunglasses) are designed this way because usually the sky is darker than the ground so if you can darken just the sky or the top half of the landscape then you can bring the exposure difference of the sky and ground closer together.  In some sunsets for instance, the sky is very bright and colourful and the ground is dark so your camera cannot expose properly for both the very dark and very bright.  So these filters help darken the sky closer to the ground so you have a better looking photo.  Personally I have not used either of these filters (unless you count the nodding in female glasses) so I cannot give any tips on their use other than they are very useful.  But you have to know what you are doing to use them since they are definitely not a beginners tool.  Also if you have a lens that extends as you zoom, you will want to be careful because you can zoom your lens into the filter because these ones do not usually screw into the front of your lens.  They are plates of glass that you attach to a holder that fits onto your lens.  

Personally I don't want to be carrying around extra plates of glass however if you want some of your landscapes to be kicked up a notch, filters can do it.  But if you are just looking for a cheap (compared to replacing or fixing a lens) protection for your lens, UV filters are a good thing to have.  Someday maybe I will get some ND filters but I want to master what I have first.

Also just recently I bought a microfibre cloth.  This is because I usually use my merino wool shirts to clean off my filters if dust or water gets on them which isn't a bright idea.  So I was cleaning my filters off yesterday actually and three of them felt a little wobbly.  Not a great feeling.  After closer inspection I did see that the adhesive or whatever is holding the glass to the metal is going.  The three filters that are lose are made by Kenko.  One is on my macro, my 50mm and the other is a 77mm filter on my 17-55mm.  The Kenko filter on my 35mm is fine but I don't use that one that much compared to the others.  However on my Tokina 11-16mm, it has a 77mm UV Hoya filter which was fine.  So Kenko isn't that top quality I guess so I will slowly start replacing my filters now.  It is a bit of a pain since a new UV filter for a 77mm diameter lens is $100.  But again, still cheaper than a new lens.  So go with top quality companies for filters like Hoya, B+W or Tiffen.  So since I have a Hoya already and I trust it I will probably upgrade all to Hoya.  It will be expensive but worth it in the long run.  

Well I hope that helps!