Do you filter your Photons ?
With a press of a button we capture speeding photons moving about 186,282 miles per second (that is the rough speed of light) as it travels into our lens and strikes our sensor and is converted into an electrical signal equaling a value which we will assign to a range from 0 (total absence, black) and 1 (total presence, white), with any fractional values in between. How do we control those values? Also how do we control the temperature (expressed as a Kelvin temperature) where warm light is redder and cool light is bluer. When we used Film we had to filter our Photons. Now with digital capture we use software in lieu of physical filters, but the Question remains, Do we still have a use for physical filters? The answer is . . . The answer is partly Yes & No.
In the years that film was king we had to use filters to control both Color and Temperature of the light and well as for special effects. These filters helped control contrast, many of which were for Black & white film such as Red, Orange, Yellow, Green. Color correction filters for use with color film to match our lighting to the film or the film to the light being used to add or subtract red or blue light from our color photos. These where called Warming filters or cooling filters and also ones to take the green out the image when shooting under fluorescent lighting. That was part of the knowledge of becoming an advanced or pro photographer, knowing the temperature of light, what filters to use. Also there were special filter tools that controlled light by removing a portion or eliminating parts of it all together. These filters where UV blockers, Polarizers, “ND” or Neutral Density and Graduated ND filters most of which where common in the Movie industry. Yes there were many different filters available and some with very special purposes of which today many can be duplicated in post processing with various software photo editing programs or add-on routines (referred to as Filters) . This leads us to the topic of this Blog . . “Do you filter your Photons” or as some say “Do you use physical filters with your digital cameras?” or do you “Do it in Photoshop” . . . Is there any real necessity to have a filter other then as a protective cover to a lens?
Well lets discuss it, The most likely answer I hear is “I’ll fix it in Photoshop” or “I can do that in Photoshop or (Insert favorite add on filter/action program)” . . but, do those filters and actions really do what the actual filter is capable of and is the results the same? In this discourse I will present my reasons for using a physical Filter rather then waiting to apply some action or software version in post. Yes I do use some filters. If you were to look in my bag you would find several types Polarizer’s, ND filters and a few specialty filters, one Filter I use often is the Polarizer . .
(Note: I will provide some useful links to further discussions or examples of the various filters I use or discussed here)
In the photo above you see the “Yellow/Blue Polarizer” by Cokin it is a very special filter and will emphasize any Blue or yellow element in your photo. As I noted I do not use this filter often as it is a very specialized filter. The most common filter for me to use is the “Circular Polarizer”, It can help saturate colors for me by removing reflections on leaves or other objects, it can intensify blue skies and make clouds seem to POP a bit more and of course can remove glare from glass or water. I can often use it to control the amount of light that strikes the sensor much like an ND filter without stopping the lens down further. This is very useful if I want movement in my photo (like waves or streams) and it can also act like a heavy duty skylight or UV filter removing some atmospheric haze. The last filter included here is the Variable ND filter, there are cheap ones and there are expensive ones, some include one element of a polarizer. The “Variable ND filter” helps me control the amount of light without using my shutter speed, aperture or ISO. This is a most usable filter but it does come with some drawbacks like most ND filters in that it can effect the color of the light and add what is called a color cast to the overall image (this can be removed later in post). We will discuss ND Filters in another paragraph later.
What is the benefit of using a physical Polarizer or waiting to apply an action in Post-Processing? I am of course a bit old school and believe that it is better to accomplish as much in camera as possible rather then in post. Using filters like the polarizer help the sensor see more saturated colors and detail by removing glare when the image is captured, I would challenge you that when this action/filter is applied in post processing that you lose both color detail and image resolution. If you shoot landscapes or waterscapes give this filter a try. Shoot several scenes with and without the filter and do a comparison, my bet is that you may agree with me about using a real Polarizer verses a Post editing filter or action meant to simulate this filter type. (You must use a Circular Polarizer with digital cameras so the AF will properly work, although you can use a regular polarizer if manually focusing). Back in the film days we had to compensate for exposure variations when using filters, today’s digital cameras read through the filter and give correct exposure without the need for compensation.
Control, Control . . . control
Filtering those Photons . . enter the ND filter (Neutral Density filter) which is basically a gray colored filter of a set density that cuts out a percentage of light. Suppose I wanted to shoot a picture but I wanted movement in the scene such as blurring waves breaking or the cascading of a waterfall or light streaks from passing cars in my scene, maybe I wanted to use a shallow depth of field but there was too much light. This is where the ND filter comes in, they allow us to control the Photons. I love long exposure photography and these help me achieve this.
Graduated ND filters come in a few types, Solid ranging from 1/2 a stop reduction to 9 stops reduction and Graduated in two types (Soft, Hard & Attenuator). The most common is a soft edge and provides a smooth transition from the ND side and the clear side. Hard edge grads have a sharp transition from ND to clear and the attenuator edge changes gradually over most of the filter so the transition is less noticeable.)
Yes there are many reasons to us a Post editing simulation of an ND filter, and the Horizon of a landscape is the primary reason, but there is a flaw in this thinking. As an example, We might would grab a Soft edge or Attenuated ND because the scene has to broad of a latitude between shadow and light, in other words in a sunset scene if we expose for the sky the foreground goes dark, if we expose for the foreground the sky washes out. In order to get this shot we either resort to two shots and a merge in Post processing, an HDR compiled in Post or we can bring this in line with a Graduated ND filter to capture detail in the sky and the foreground. Later in post I can tweak. I might do two of the above if time permits, also I might do the same for experimentation purposes, but the one thing about film that has carried over to digital. If you record Zero data in a white area, there is nothing there to recover in post with software, even in raw. I opt for exposing for the highlights if possible and keeping details in the shadows.
So the question remains, real filters? or Post simulations of filters? I will only say this, each is a valued tool and each has its place. I prefer to stack the odds in my favor and use real Filters. There are cheap ones medium priced one and some that are trinkets for those with too much money in their pockets. Glass or Plastic? either works. Coated/non-coated? You decide, coated are harder to clean, if shooting in a dirty area use a non or single coated lens, the coating cut glare. Protective filters? Heck yeah, $30.00 is chump change protections compared to the bill for replacing a scratched front lens element. Plastic filters like Coken can scratch easily but cost less, glass do not scratch as easily but the cost can be very high. Buy filters one size larger or as large as your biggest lens and use a step down ring so they fit every lens, by doing this you can save a few $$ on not having to buy a specialty filter for each lens. Do buy individual protective filters for each of your lenses. Stacking filters on wide angle lenses can cause vignetting so you might invest in slim designs but they do cost more. There are many resources online to explain what each filter does.
My filters in order of use
– Circular Polarizer
– 9 stop Variable ND Filter
– Solid & Attenuated ND filers in various densities, Solids ND2, ND4, ND8, ND16
Well there you have it, and yes I do filter my Photons, I also use several Post editing programs and add on components. My fave programs are “Capture One by Phase One”, “Adobe Lightroom”, “Corel Paint Shop Pro”, “On One Suite 7.X (most used)” These are all tools I use in my daily editing of my digital imaging. Filters by Coken, Hoya are mostly used for landscape photography, I would recommend a good polarizer.
Filters no longer needed or used except for film, All Black and White contrast filters, Color temp correction filters as White-Balance can be adjusted in RAW in post on digital edits, the exception would be an artistic application. I seldom use any of the old artistic filters but would recommend investigating them as you may find some are really cool. I still on occasion use a homemade soft focus filter made from black or white pantyhose (it provides a different look then a digital soft filter) . . . experiment, explore . . . don’t just think “What if” . . do it, your digital camera demands it . .
Links to further information, these links are to Luminous Landscape web pages, The authors and contributors have done a lot of research, No they are not the last word on these subjects, no one is . . . but the information provided is worth its weight. We all need to explore, educate, grow and play as photographers . . . these are tools that help you get the best photo you can . . .
until next time, Thank you for reading my blog, I hope you enjoyed and if you did please share it . . So get up, get out and shoot. . .
up coming post idea “Razor blades, foamcore & gaffers tape”
So . . . Do you filter your Photons?