To use Filters or not to

January 19, 2014  •  Leave a Comment

To use filters or not to

Every photography sales person wants to sell you filters because they generally have high profit margins. They always seem to ask: don't you want to protect your $1,000.00 lens? Or they may say: it is much cheaper to damage a $25.00 protective filter (UV filter) than the front lens element of your $1,000.00 lens. May I please ask a counter question: what does a $25.00 filter do to the image quality of your $1,000.00 lens? If you place a piece of junk in front of your lens your lens just became a piece of junk, because the bad filter only lets bad light through to your lens. I will never use any kind of protective filter (see one exception below). So what about my expensive lens? The best protection is called a lens cap. It is cheap and works just perfectly. I have been around photographers for well over 25 years and I have never heard of any of them getting their lens scratched while they are busy shooting. The damage usually comes while walking or doing things other than looking through the view finder. So the risk of your lens being scratched while you shoot is low. Using a lens cap while not shooting covers you for everything else. There is one exception; water or ocean spray. If you shoot in these conditions a filter as protection is a good idea. However, not the $25.00 one. I use my good quality polarizer rather than a protective filter.

Then you also get the folk on the other side of the spectrum; they never use any kind of filters because "in the digital age you can do anything with your computer in post processing." While you can do amazing things in post processing I like to get the image right in camera rather than sitting in front of my computer for hours and hours; I just don't have the time and even if I did, I would rather be shooting than sitting in front of my computer. So which filters do I use and why?

Graduated Neutral Density Filters

These filters do not effect the color of your image in any way. They simply let less light through on one side of the filter than the other (or top and bottom). Here is the problem. Your eyes can see detail in both bright and dark areas at the same time, but your camera cannot. Successful photographers learn to see the way their cameras do. Your camera will either expose your light areas correctly with no detail in the dark areas or it will correctly expose the dark areas leaving the bright areas devoid of detail. It is usually the sky or top part of the image that is too bright. By placing the dark part of the filter over the light part of the image it "steals" two or three F.Stops of light (only from the light part because the bottom part of the filter is clear). In this way the difference in light intensity between the light and dark areas of the image is reduced by two or three F.Stops bringing it in line with what your camera can see. Using this filter is easy and quick. Yes, it can be done on the computer. Yes, you can also use High Dynamic Range Photography (which I do not find particularly attractive). However, I can hold my filter in front of my lens in two seconds making a huge positive difference in my image right away and in camera; and I am done. Please stay away from the cheap brands because they are not really neutral; they produce a color cast and they may degrade your image quality over all.

Here is an example. The sky was too bright (in fact, the sky what three times brighter than what you see here). Shot without a graduated neutral density filter I would have had to make one of two choices. Either expose for the sky, but then the foreground (especially the rock face in the middle right of the image) would have been too dark, or expose for the foreground leaving the sky too bright. Holding the filter in place "darkens the sky" so that the light is within range of the camera's sensor to capture. I used a three stop filter here reducing the amount of light by three times.

Circular Polarizers

As far as I know software is still not good enough to replace a polarizer. A polarizer removes reflections from water, sheen from leaves, and makes clouds pop a little. Saturation may also be boosted just a tad. I use a polarizer almost all the time. Please do not use a polarizer when shooting with a wide angle lens (or shooting panoramas). Polarizers work best at a 90 degree angle to the sun. The angle of view with a wide angle lens using a polarizer results in different shades of blue in the sky, where at 90 degrees from the sun the sky is bluer (and darker) than the rest of the image. This is a nightmare to try and fix with software. On lenses other than wide angles a polarizer works great. High altitude shooting (if your image includes sky) requires less polarization so do not over do it, your sky will not look natural (too dark and too blue). Once again, only use good filters because you do not want to degrade the light reaching your lens. Good light is what photography is all about.

That is it. I don't use any other filters. Some of my friends use neutral density filters to enable them to use longer shutter speeds to blur water movement. I have not been converted to this idea yet. Shoot in lower light and use a polarizer (which also steals up to two stops of light). I know that shooting in lower light is not always an option, but I have just not seen many good images taken at the wrong time (less than ideal light) which became good because of a neutral density filter.

Happy shooting.


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