12 Dec Q & A – Lens Filters
It’s a topic photographers start to tackle as they continue to develop their skills, continue to tackle new subject matter, and continue to tackle the processes in order to capture better photographs. Of course, all of these photographic avenues we try to improve ultimately trickle down to the same solution, much like the branches of a tree to the trunk, and that is – the betterment of capturing light. Each photograph – a simple exposure to light. There are literally an infinite number of situations in which a camera can be asked to best capture that pesky stuff we call “light.” Some of these situations can best be captured by simply fully understanding how to use a camera and how to spin the dials, some may call for the use of a reflector, diffuser, or even an addition of a light source, and some require the introduction of a filter to best capture the moment. In this article, we’ll be taking a look at the latter, an in-depth look at the various filters available to photographers, which ones to avoid, correct and incorrect uses, and when to best use them. The importance of using filters in your work will largely depend on the type of photography you capture. They can have a very dramatic or very little effect on your image, depending on your knowledge of how and when to use them.
There are a number of different filter types out there, some for more generalized purposes, and some for very specific photo tasks. I will only be tackling the more general, widely-used filters in this post. So by no means am I covering the entire spectrum of what is available out on the market for filters.
There are many reasons photographers might be hunting for a filter, and unfortunately, sometimes it can be completely for the wrong reasons. Protection is one of the WRONG reasons to buy a filter. Green photographers will often seek-out a basic, clear filter for the simple purpose of protecting the front element of glass on their lens. If you are newer to photography, you might still be a little clumsy in handling your camera equipment, you might be overly concerned with dropping or scratching up the front element of your lenses. Here are my thoughts protecting the front or your lenses…
Filters should NOT be used for protecting your lens. Of course we are all on-board with wanting to keep the front of our lenses clean and untouched, but there are better ways to do this so that you are not compromising image quality by adding another layer of glass to your images. Use a lens hood for this purpose. Lens hoods extend well beyond the front of the lens, protect the lens from getting touched, banged, etc. A lens hood’s primary function is to reduce unwanted lens flares as a result from side/back light leaking into the lens, which also helps maximize your contrast and saturation levels, however, rarely do I think of hoods as help with this purpose, and you’ll find that they help WAY more in the damage control department. I use lens hoods 100% of the time, and my primary reason for using them IS protection, but it’s also nice the they are there to help block unwanted light.
If you are new to the game, you should have relatively entry-level gear (this is a good thing, as in the event you happen to scratch, drop, or otherwise damage a piece of gear, it is going to be much easier to accept you ruined a $100 lens rather than a $2000 lens, and replacement/repair costs will minimal). As you progress in photography, you’ll become more comfortable with the gear, handling it, and your risk of scratching, dropping/damaging equipment will decrease. Later down the road, your experienced hands will more accurately and confidently handle nicer, more expensive gear, but the same holds true – do not use filters for protection purposes, use hoods for that. The ONLY disclaimer I have to add to using filters for protection purposes is if you were going to use your camera in an extreme environment, like going into the desert or sticking it out your car window where a bug could smack the lens at 70mph. If you are going to purposefully put your camera in harms way, then sure, put a basic filter on for your reckless moments, and then take it off.
The Right Purpose
This information holds true with everything in life, and that is – ensure you have a good understanding of any filters you are using to maximize photo potential. This means knowing how each filter effects your images (both positively and negatively) so that you can make a call on when and how to use a particular filter. Filters are pretty easy to mount and unmount, so don’t think just because you walked out of the house that day with a filter on that it has to endure the entire day mounted to your lens. Worst case scenario, you mount the wrong filter to use for the wrong purpose, due to lack of understand what a particular filter’s true abilities are for. So let’s take a look at couple filters now.
The UV/HAZE filter is the first filter I think most people get wrangled into buying. This is a clear filter that is supposed to help with stray light and haze. This is the filter most people buy who are looking to add a layer of protection to their lens, as it does not effect the light entering the lens. In my opinion, these lenses are a waste of time and money, and I do not see any benefit this has over a lens hood. Again, if you are in an extreme environment where you know there is a good chance of something making direct contact with your lens, put one on for protection, but it’s about the only thing these are good for.
Now here is a filter you should invest in. There is a bit of science behind this guy, but I’ll let you wiki the geeky details, and I will just get to the good parts for why you should own this filter. A polarizer works wonders by blocking certain angles of light from entering the lens, and by doing so, you can get the upper hand in many typical shooting situations.
If you shoot landscape photography… how do I put this simply… you are an idiot if you do not own this filter. A polarizer will add dramatic increases in color and contrast in skies, pull the reflections off of water, foliage, and other surfaces. By blocking these reflections, the true color and details of the objects will enter the lens, and not reflected light bouncing off of these objects (usually sunlight). You’ll see the biggest advantage in mid-day light, when the sun is high, but also when you’ll be seeing the biggest rob of contrast and saturation in your images. There’s a reason for that, because the sun’s light is bouncing off of everything, and you lose visibility of all of the colors because your eyes (or lens in this case) is seeing mostly reflected sunlight bouncing off of the objects. The photo at the top of the post was taken with a polarizer at almost noon (the worst time to take outdoor photographs). With the filter on, I was able to pull good color out of the ground and sky, and without the filter this image would be super bland.
This filter is handy in general with walk-around photographers, as we encounter reflections no matter where we go, and you are probably getting robbed of color in a lot of images because of reflections you are unaware of (and how dramatically they are robbing your photos of contrast and color). Ever want to take a photo of someone sitting in a car behind a window, or maybe you are walking down the street and see something cool in a store window and want to take an image of it. Usually without a filter, this image situation always fails, as your camera will only be able to “see” the reflected light on the surface of the window glass. With a polarizer you can completely filter-out this reflected light, and see into the window. The same is true with any other surface that is reflecting direct light, like water, plants, walls, whatever.
To effectively use a polarizer, first make sure that you are dealing with a polarized light source, like the sun. With the filter on your lens, look through the viewfinder and the scene you are about to photograph. Spin the filter and watch how the light entering the camera is effected. By rotating the filter, you are changing the direction of polarized light being filtered out of the lens. For example, if you are shooting a landscape and want that deep, dark blue sky, rotate the lens and watch the sky change. Spin and adjust a couple times until you’ve found the sweet spot. Polarizers are manually intensive, meaning you’ll need to adjust them just as much as you are recomposing various images. Remember, if you flip your camera from a landscape to a portrait framing, you’ve just turned your filter 90 degrees as well. Don’t think that you are done and will get the pictures you want by simply mounting the polarizer, it needs a lot of attention.
If you are working with flash lighting (which is not polarized) you will not be getting any benefit from a polarizer. Again, wiki this topic to form a better understanding of the details.
In my line of work, I am usually capturing portraits, but that doesn’t mean that I never use a polarizer. It can be a very complementary tool in my line of work. Often I’m on-location and shooting outdoors, and even though I am utilizing off-camera lighting, I’m often working with a skyline as a backdrop. So I’m working with both flash lighting (non-polarized) and the sun (polarized). The polarizer will not effect the light falling on my subject, but definitely will on my background which is being lit by the sun. If I want to add contrast and saturation to my background, I’ll add the polarizer. Below are a couple images I’ve recently captured where I’ve taken advantage of a polarizer (for both color in the sky and make the mountain “pop” in the background).
Without the polarizer, these particular images would not have the same look and feel, in regards to the background (which happened to be extremely important in this shoot).
As far as a general use filter, I think a polarizer is the one to own. There are just so many practical uses where it can enhance your photos ranging from barely to dramatically.
Here is a wiki page with some great examples of leveraging a polarizer (click here).
Neutral Density Filter
Think of a neutral density (ND) filter as a pair of sunglasses for your lens. It’s sole purpose is to knock light down as it enters your lens. It’s called “neutral” because it does not otherwise effect the light entering the lens via color and manipulation. ND filters are measured in “stops,” a term all photographers should be familiar with (a stop of light is the equivalent of doubling or cutting the light in half). In this case, an ND filter always subtracts stops of light from entering the lens. ND filters can be acquired in single or multiple-stop increments (you can stack ND filters on top of each other to cut more light from the lens). You can also buy variable-stop ND filters, which can be adjusted by spinning the filter, this is the route I chose to go. My ND filter has a 2-8 stop range, which is adjusted by spinning the filter.
You might be asking yourself when an ND filter would come in handy, as most of us are always looking for ways to add MORE light to our photographs. One of the key areas where they can be utilized is long exposure photography. Sure, long exposures are easy to snag when it’s nighttime, or at dusk, but what if you want the effects of long exposure in the middle of the day? ND filter to the rescue. What if you want to shoot a low aperture (like F4), resulting in a shallow DOF, but it’s so bright out that you are being forced to stop down to F16? Slap on a couple stops of ND to make it happen. There are other occasions, like in my portrait example above, that you are trying to balance off-camera lighting with ambient, and ND filters can help out there as well.
There is one variation of the ND filter that is worth mentioning, and that is a graduated ND filter. The graduated version has a gradient fade, so that it’s darker on one end and fades to a lighter tint on the other (much like a pair of sunglasses that have a faded tint, with more shading on the top and less on the bottom). These can be best utilized where you have a hot spot in your image, however, you want the entire image to be exposed evenly. Ex. is a typical sunset photograph, say… on a beach. You are exposing the photograph for the sunset, but normally this would leave the water and beach area of the photograph super dark because it is not nearly as bright as the sky you are exposing for. Add the graduated ND filter, with the darker portion on top. This will knockout some of the light of the sunset, which will allow you to get a better balanced exposure for the entire scene.
There Are Others
There are lots of specialized lens filters out on the market, however, I think the ones I’ve covered above will fit most, if not all, of your general photography needs. There are color filters, warming filters, cooling filters, the list goes on. As your photographic journey matures, you may find yourself looking for more specialized filters to fit your very specialized needs.
The digital age has given us the ability to do away with a lot of these specialized filters because of the power we now have in post software. Of course, you want to do the job right at time of capture, and I believe that the filters recommended above will answer that call, manipulating light accordingly, while many of the other filters available can be properly replicated in digital post production. For example, we don’t need to limit our camera by setting it to take a black and white exposure, when you can simply take the color photo in post and turn it black and white. This leaves you with the flexibility of both a color and B&W photo. The same holds true with a lot of specialized filters out there. Why use a warming filter when you can warm the photo in post? Gone are the days of film, and digital fortunately frees us of a lot of the at-capture necessities.
Minimize Filter Usage
Limit filter use to ONLY when they are serving a direct benefit to your image, and take them off when they are not required. You pay a lot of money for really nice lenses and the glass elements that are designed in them. It’s very important to keep in-mind that adding an extra layer of glass will only degrade your image quality. It’s a give-take scenario, degrading overall image quality by introducing another layer of glass for the light to passthrough, versus the light altering benefits from the filter. Keep this in-mind when you are shopping for filters as well. When it comes to that that $1000+ pro lens you have… are you going to buy a $20 or $200 filter? Your image will only be as strong as it’s weakest element, and we don’t have to guess what that weakest link is if you settled for that $20 special. You shouldn’t get super paranoid about filter glass quality and it’s degrading effects on your final image, however, it’s something to consider when you are shopping and really need something that will produce the best image possible.
Your subject matter in photography should be your guide in filter usage. There is no universal lens filter to make all of your images better, so only use them for their intended purpose, and make the most of out of the light in your world.